0001715768-21-000088 | 10-KT | XBRL Viewer

Cover - USD ($) $ in Thousands	3 Months Ended
Cover - USD ($) $ in Thousands	Mar. 31, 2021	Jun. 10, 2021	Sep. 30, 2020
Cover [Abstract]
Document Type	10-KT
Document Annual Report	false
Document Period End Date	Mar. 31, 2021
Current Fiscal Year End Date	--03-31
Document Transition Report	true
Entity File Number	000-55832
Entity Registrant Name	Transphorm, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-1858829
Entity Address, Address Line One	75 Castilian Drive
Entity Address, City or Town	Goleta,
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	93117
City Area Code	805
Local Phone Number	456-1300
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 46,627,426
Entity Common Stock, Shares Outstanding		40,564,921
Documents Incorporated by Reference	None.
Entity Central Index Key	0001715768
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Document Period Start Date	Jan. 01, 2021

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 9,500	$ 14,694	$ 2,875
Accounts receivable, net, including $507 thousand, $442 thousand, $464 thousand from related parties as of March 31, 2021, December 31, 2020 and December 31, 2019, respectively	1,618	844	709
Inventory	2,223	1,627	990
Prepaid expenses and other current assets	953	1,061	783
Total current assets	14,294	18,226	5,357
Property and equipment, net	1,360	1,324	1,770
Goodwill	1,302	1,397	1,325
Intangible assets, net	914	988	1,313
Other assets	274	291	497
Total assets	18,144	22,226	10,262
Current liabilities:
Accounts payable and accrued expenses	3,140	3,182	2,383
Deferred revenue	505	674	0
Development loan	10,000	10,000	5,000
Revolving credit facility, including accrued interest	10,150	10,153	10,458
Unfunded commitment to joint venture	1,866	1,466	1,688
Accrued payroll and benefits	1,410	1,215	1,159
Total current liabilities	27,071	26,690	20,688
Development loans, net of current portion	0	0	10,000
Promissory note	16,128	15,392	16,169
Total liabilities	43,199	42,082	46,857
Commitments and contingencies (Note 11)
Total convertible preferred stock	0	0	85,658
Stockholders’ deficit:
Common stock, $0.0001 par value; 750,000,000 shares authorized as of March 31, 2021 and December 31, 2020, and 40,531,996 and 40,278,496 shares issued and outstanding as of March 31, 2021 and December 31, 2020, respectively; 29,012,034 shares authorized and 4,220,998 shares issued and outstanding as of December 31, 2019	4	4	0
Additional paid-in capital	144,201	142,736	22,404
Accumulated deficit	(168,403)	(161,824)	(143,915)
Accumulated other comprehensive loss	(857)	(772)	(742)
Total stockholders’ deficit	(25,055)	(19,856)	(122,253)
Total liabilities, convertible preferred stock and stockholders’ deficit	18,144	22,226	10,262
Series 1 Preferred Stock
Current liabilities:
Total convertible preferred stock	0	0	39,658
Series 2 Preferred Stock
Current liabilities:
Total convertible preferred stock	0	0	30,000
Series 3 Preferred Stock
Current liabilities:
Total convertible preferred stock	$ 0	$ 0	$ 16,000

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounts receivable due from related parties	$ 507	$ 442	$ 464
Common stock, par value (in usd per share)	$ 0.0001	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	750,000,000	750,000,000	29,012,034
Common stock, shares issued (in shares)	40,531,996	40,531,996	4,220,998
Common stock, shares outstanding (in shares)	40,278,496	40,278,496	4,220,998
Series 1 Preferred Stock
Convertible preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001	$ 0.0001
Convertible preferred stock, authorized (in shares)	0	0	12,438,704
Convertible preferred stock, shares issued (in shares)	0	0	12,433,953
Convertible preferred stock, shares outstanding (in shares)	0	0	12,433,953
Series 2 Preferred Stock
Convertible preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001	$ 0.0001
Convertible preferred stock, authorized (in shares)	0	0	7,507,699
Convertible preferred stock, shares issued (in shares)	0	0	7,499,996
Convertible preferred stock, shares outstanding (in shares)	0	0	7,499,996
Series 3 Preferred Stock
Convertible preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001	$ 0.0001
Convertible preferred stock, authorized (in shares)	0		4,000,000
Convertible preferred stock, shares issued (in shares)	0		4,000,000
Convertible preferred stock, shares outstanding (in shares)	0		4,000,000

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenue, net, including related parties (Note 17)	$ 2,425	$ 1,100	$ 11,371	$ 11,934
Operating expenses:
Cost of goods sold	1,788	1,455	6,682	6,492
Research and development	1,780	1,466	5,584	8,146
Sales and marketing	663	518	2,174	2,609
General and administrative	2,733	3,092	10,328	6,606
Total operating expenses	6,964	6,531	24,768	23,853
Loss from operations	(4,539)	(5,431)	(13,397)	(11,919)
Interest expense	187	189	760	758
Loss in joint venture	1,468	1,419	6,836	3,703
Changes in fair value of promissory note	699	(2,321)	(927)	167
Other income, net	(314)	(531)	(2,157)	(1,264)
Loss before tax expense	(6,579)	(4,187)	(17,909)	(15,283)
Tax expense	0	0	0	0
Net loss	$ (6,579)	$ (4,187)	$ (17,909)	$ (15,283)
Net loss per share - basic and diluted (in usd per share)	$ (0.16)	$ (0.13)	$ (0.56)	$ (0.54)
Weighted average common shares outstanding - basic and diluted (in shares)	40,274,660	31,912,170	31,739,801	28,153,605

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net loss	$ (6,579)	$ (4,187)	$ (17,909)	$ (15,283)
Other comprehensive loss, net of tax:
Foreign currency translation adjustments	(85)	(12)	(30)	(2)
Other comprehensive loss, net of tax	(85)	(12)	(30)	(2)
Comprehensive loss	$ (6,664)	$ (4,199)	$ (17,939)	$ (15,285)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

Consolidated Statements of Changes in Stockholders’ Deficit - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss
Beginning balance (in shares) at Dec. 31, 2018		4,219,606
Beginning balance at Dec. 31, 2018	$ (107,539)	$ 0	$ 21,833	$ (128,632)	$ (740)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)	1,392	1,392
Stock options exercised, net of $5 receivable	$ 5		5
Stock-based compensation	566		566
Other comprehensive income	(2)				(2)
Net loss	$ (15,283)			(15,283)
Ending balance (in shares) at Dec. 31, 2019	4,220,998	4,220,998
Ending balance at Dec. 31, 2019	$ (122,253)	$ 0	22,404	(143,915)	(742)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)		3,346
Stock options exercised, net of $5 receivable	13		13
Stock-based compensation	132		132
Conversion of shares in connection with the Reverse Merger (in shares)		23,933,949
Conversion of preferred shares in connection with the Reverse Merger	85,658	$ 3	85,655
Shares redeemed (in shares)		(52,773)
Shares redeemed in connection with the Reverse Merger	(211)		(211)
Shares issued in connection with the Reverse Merger (in shares)		1,650,000
Shares issued in connection with the Reverse Merger	(50)		(50)
Issuance of common stock, net (in shares)		5,380,000
Issuance of common stock, net of $3.1 million offering cost excluding warrant cost of $223 thousand	19,741	$ 1	19,740
Other comprehensive income	(12)				(12)
Net loss	(4,187)			(4,187)
Ending balance (in shares) at Mar. 31, 2020		35,135,520
Ending balance at Mar. 31, 2020	$ (21,169)	$ 4	127,683	(148,102)	(754)
Beginning balance (in shares) at Dec. 31, 2019	4,220,998	4,220,998
Beginning balance at Dec. 31, 2019	$ (122,253)	$ 0	22,404	(143,915)	(742)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)	6,821	6,821
Stock options exercised, net of $5 receivable	$ 27		27
Restricted stocks issued (in shares)	139,501
Stock-based compensation	$ 1,525		1,525
Conversion of shares in connection with the Reverse Merger (in shares)		23,933,949
Conversion of preferred shares in connection with the Reverse Merger	85,658	$ 3	85,655
Shares redeemed (in shares)		(52,773)
Shares redeemed in connection with the Reverse Merger	(211)		(211)
Shares issued in connection with the Reverse Merger (in shares)		1,650,000
Shares issued in connection with the Reverse Merger	(50)		(50)
Issuance of common stock, net (in shares)		10,380,000
Issuance of common stock, net of $3.1 million offering cost excluding warrant cost of $223 thousand	33,387	$ 1	33,386
Other comprehensive income	(30)				(30)
Net loss	$ (17,909)			(17,909)
Ending balance (in shares) at Dec. 31, 2020	40,278,496	40,278,496
Ending balance at Dec. 31, 2020	$ (19,856)	$ 4	142,736	(161,824)	(772)
Beginning balance (in shares) at Feb. 11, 2020	50,325,662
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued in connection with the Reverse Merger (in shares)	1,650,000
Ending balance (in shares) at Feb. 12, 2020	4,171,571
Beginning balance (in shares) at Dec. 31, 2020	40,278,496	40,278,496
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised (in shares)	500	500
Stock options exercised, net of $5 receivable	$ 2		2
Restricted stocks issued (in shares)	3,000
Stock-based compensation	$ 513		513
Issuance of common stock, net (in shares)		250,000
Issuance of common stock, net of $3.1 million offering cost excluding warrant cost of $223 thousand	950		950
Other comprehensive income	(85)				(85)
Net loss	$ (6,579)			(6,579)
Ending balance (in shares) at Mar. 31, 2021	40,278,496	40,531,996
Ending balance at Mar. 31, 2021	$ (25,055)	$ 4	$ 144,201	$ (168,403)	$ (857)

Consolidated Statements of Changes in Shareholders' Deficit (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) shares
Statement of Stockholders' Equity [Abstract]
Stock options exercised, receivable	$ 5
Stock issuance costs	3,100
Payment of warrant offering costs	$ 223
Common stock, shares outstanding (in shares) \| shares	40,278,496
Stockholders' Equity Attributable to Parent	$ (19,856)
Stock options exercised (in shares) \| shares	6,821
Stock options exercised, net of $5 receivable	$ 27
Stock-based compensation	1,525
Conversion of preferred shares in connection with the Reverse Merger	85,658
Stock Repurchased During Period, Value	(211)
Shares issued in connection with the Reverse Merger	(50)
Issuance of common stock, net of $3.1 million offering cost excluding warrant cost of $223 thousand	33,387
Other comprehensive income	(30)
Net loss	$ (17,909)

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net loss	$ (6,579)	$ (4,187)	$ (17,909)	$ (15,283)
Adjustments to reconcile net loss to net cash used in operating activities:
Inventory write-off	7	169	435	155
Depreciation and amortization	197	236	835	1,216
(Recovery from) provision for doubtful accounts	(48)	0	110	0
Licensing revenue from a related party	0	0	(5,000)	0
Stock-based compensation	513	132	1,525	566
Interest cost	187	189	760	608
Gain on sale of equipment	(40)	0	0	0
Loss in joint venture	1,468	1,419	6,836	3,703
Changes in fair value of promissory note	699	(2,321)	(927)	167
Changes in operating assets and liabilities:
Accounts receivable	(690)	(668)	(245)	(429)
Inventory	(603)	(264)	(1,072)	(293)
Prepaid expenses and other current assets	108	(603)	(283)	(154)
Other assets	17	9	206	(42)
Accounts payable and accrued expenses	(195)	(179)	(116)	509
Deferred revenue	(169)	0	674	(3,000)
Accrued payroll and benefits	195	(83)	56	(13)
Net cash used in operating activities	(4,933)	(6,151)	(14,115)	(12,290)
Cash flows from investing activities:
Purchases of property and equipment	(164)	0	(58)	(203)
Investment in joint venture	(968)	(1,548)	(7,348)	(2,698)
Net cash used in investing activities	(1,132)	(1,548)	(7,406)	(2,901)
Cash flows from financing activities:
Proceeds from sale of equipment	4	0	0	0
Proceeds from development loans	0	0	0	15,000
Proceeds from stock option exercise	2	18	32	0
Payment for repurchase of common stock	0	(211)	(211)	0
Loan repayment	0	(50)	(50)	0
Proceeds from issuance of common stock, net of offering cost	950	19,741	33,387	0
Net cash provided by financing activities	956	19,498	33,158	15,000
Effect of foreign exchange rate changes on cash and cash equivalents	(85)	(26)	182	(3)
Net (decrease) increase in cash and cash equivalents	(5,194)	11,773	11,819	(194)
Cash and cash equivalents at beginning of period	14,694	2,875	2,875	3,069
Cash and cash equivalents at end of period	9,500	14,648	14,694	2,875
Supplemental disclosures of cash flow information:
Interest expense paid	153	0	915	496
Supplemental non-cash financing activity:
Private placement offering cost	0	0	223	177
Development loan reduction related to licensing revenue	0	0	5,000	0
Conversion of preferred stock to common stock in connection with the Reverse Merger	$ 0	$ 85,658	$ 85,658	$ 0

Business and Basis of Presentation	3 Months Ended
Business and Basis of Presentation	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business and Basis of Presentation	Business and Basis of Presentation Transphorm, Inc. (“Parent”) develops gallium nitride (“GaN”) semiconductor components used in power conversion and is headquartered in Goleta, California. Parent’s wholly owned-subsidiary, Transphorm Technology, Inc., was incorporated in the State of Delaware on February 22, 2007. Throughout these notes, “the Company,” “Transphorm,” “we,” “us” and “our” refer to Parent and its direct and indirect wholly-owned subsidiaries. Transphorm Technology and its subsidiaries hold all material assets and conduct all business activities and operations of the Company. Transphorm Technology’s activities to date have been primarily performing research and development, establishing manufacturing infrastructure, market sampling, product launch, hiring personnel, and raising capital to support and expand these activities. Transphorm Japan, Inc. was established in Japan in February 2014 to secure Transphorm’s production capacity and establish a direct presence in Asian markets. Transphorm Aizu, Inc. was established in Japan to manage the financial transactions around Aizu Fujitsu Semiconductor Wafer Solution Limited, Transphorm’s non-controlling joint venture wafer fabrication facility located in Aizu Wakamatsu, Japan (“Aizu”). Transphorm Japan Epi, Inc. was established in Japan in 2019 to enable the operational capacity of the reactors held in Aizu. Change in Fiscal Year End On April 20, 2021, we changed our fiscal year from the period beginning on January 1 and ending on December 31 to the period beginning on April 1 and ending on March 31 of each year, effective immediately. Accordingly, we are filing this Transition Report on Form 10-K (this “Report”) to include audited consolidated financial information for the transition period from January 1, 2021 through March 31, 2021. Reverse Merger On February 12, 2020, our wholly-owned subsidiary, Peninsula Acquisition Sub, Inc., a corporation formed in the State of Delaware (“Acquisition Sub”), merged with and into Transphorm Technology (formerly known as Transphorm, Inc.), the corporate existence of Acquisition Sub ceased, and Transphorm Technology became our wholly-owned subsidiary (such transaction, the “Merger”). As a result of the Merger, we acquired the business of Transphorm Technology. The Merger was effective as of February 12, 2020, upon the filing of a certificate of merger with the Secretary of State of the State of Delaware. Immediately after completion of the Merger, we adopted Transphorm Technology’s former company name, “Transphorm, Inc.”, as our company name. The Merger was treated as a recapitalization and reverse acquisition for financial reporting purposes, and Transphorm Technology is considered the acquirer for accounting purposes. As a result of the Merger and the change in our business and operations, a discussion of the past financial results of our predecessor, Peninsula Acquisition Corporation, is not pertinent, and under applicable accounting principles, the historical financial results of Transphorm Technology, the accounting acquirer, prior to the Merger are considered our historical financial results. At the effective time of the Merger, (i) each share of Transphorm Technology’s common stock issued and outstanding immediately prior to the closing of the Merger was converted into the right to receive (a) 0.08289152527 shares of our common stock (in the case of shares held by accredited investors) or (b) $4.00 multiplied by 0.08289152527 (in the case of shares held by unaccredited investors), with the actual number of shares of our common stock issued to the former holders of Transphorm Technology’s common stock equal to 4,171,571, (ii) 51,680,254 shares of Transphorm Technology’s Series 1 preferred stock issued and outstanding immediately prior to the closing of the Merger were converted into 12,433,953 shares of our common stock, (iii) 38,760,190 shares of Transphorm Technology’s Series 2 preferred stock issued and outstanding immediately prior to the closing of the Merger were converted into 7,499,996 shares of our common stock, and (iv) 31,850,304 shares of Transphorm Technology’s Series 3 preferred stock issued and outstanding immediately prior to the closing of the Merger were converted into 4,000,000 shares of our common stock. As a result, 28,105,520 shares of our common stock were issued to the former holders of Transphorm Technology’s issued and outstanding capital stock after adjustments due to rounding for fractional shares. Immediately prior to the effective time of the Merger, an aggregate of 682,699 shares of our common stock, owned by the stockholders of Peninsula Acquisition Corporation prior to the Merger, were forfeited and cancelled. In addition, pursuant to the Merger Agreement, (i) options to purchase 29,703,285 shares of Transphorm Technology’s common stock issued and outstanding immediately prior to the closing of the Merger under Transphorm Technology’s 2007 Stock Plan (the “2007 Plan”) and 2015 Equity Incentive Plan (the “2015 Plan”) were assumed and converted into options to purchase 2,461,923 shares of our common stock, (ii) warrants to purchase 186,535 shares of Transphorm Technology’s common stock issued and outstanding immediately prior to the closing of the Merger were assumed, amended and converted into warrants to purchase 15,461 shares of our common stock, and (iii) Transphorm Technology’s outstanding convertible promissory note was amended to be convertible at the option of the holder, into shares of our common stock at a conversion price of $5.12 per share, with 3,076,171 being the maximum number of shares of our common stock issuable upon conversion of the convertible promissory note. As of December 31, 2020, there was $15.0 million of principal and $486 thousand of accrued and unpaid interest outstanding on the convertible promissory note. All per share and share amounts for the year ended December 31, 2019 have been retroactively adjusted to reflect the effect of the Merger. Going Concern The accompanying consolidated financial statements have been prepared assuming that the Company will continue as a going concern. As included in the accompanying consolidated financial statements, the Company has generated recurring losses from operations, sustained negative cash flows from operating activities, and has an accumulated deficit and has a working capital deficiency. These factors raise substantial doubt about the Company’s ability to continue as a going concern for the next twelve months from the issuance of these financial statements. Management plans to raise additional working capital to fund operations through the issuance of stock to investors, license of intellectual property and/or issuance of notes payable. The Company raised $1.0 million, $19.7 million and $13.6 million from the sales of common stock in March 31, 2021, February 2020 and December 2020, respectively, as described in Note 13 - Stockholders’ Equity. However, there is no assurance that the Company will be successful in raising additional capital. The ability of the Company to continue as a going concern is dependent on its ability to raise significant additional capital to fund operating losses until it is able to generate liquidity from its business operations. To the extent sufficient financing is not available, the Company may not be able to, or may be delayed in, developing its offerings and meeting its obligations. The Company will continue to evaluate its projected expenditures relative to its available cash and to evaluate financing alternatives in order to satisfy its working capital and other cash requirements. The accompanying consolidated financial statements do not reflect any adjustments that might result from the outcome of these uncertainties. Impact of COVID-19 on Our Business The COVID-19 pandemic has adversely disrupted and will further disrupt the operations at certain of our customers, partners, suppliers and other third-party providers for an uncertain period of time, including as a result of travel restrictions, adverse effects on budget planning processes, business deterioration, and/or business shutdowns, all of which has impacted our business and results of operations. Some of our customers have experienced delays in their internal development programs and design cycles with our GaN products due to the effects of COVID-19, which have led to postponements of their orders of our products and postponements of determinations that our products will be used in their designs for new products under development with corresponding delays in their market introduction and our revenues. The future impact of COVID-19 cannot be predicted with certainty and may make it more difficult or preclude us from raising additional capital, increase our costs of capital and otherwise adversely affect our business, results of operations, financial condition and liquidity.

Summary of Significant Accounting Policies	3 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Principles of Consolidation The consolidated financial statements include the accounts of the Parent and its wholly-owned subsidiaries, Transphorm Technology, Transphorm Japan, Inc., Transphorm Japan Epi, Inc. and Transphorm Aizu, Inc. Upon consolidation, all significant intercompany accounts and transactions have been eliminated. Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Management bases its estimates and assumptions on historical experience, knowledge of current conditions, and its belief of what could occur in the future, given available information. Actual results could differ from those estimates, and such differences could be material to the consolidated financial statements. Estimates are used for, but not limited to, the determinations of fair value of stock awards and promissory notes, accrual of liabilities, revenue recognition, inventory reserve, and useful lives for property and equipment. Cash and Cash Equivalents The Company considers all highly-liquid investments with original maturities of 90 days or less at the date of purchase to be cash equivalents. Cash and cash equivalents consist principally of bank deposits and money market funds. Other assets in the consolidated balance sheets as of March 31, 2021, December 31, 2020 and December 31, 2019 include restricted cash of $75 thousand. Foreign Currency Risk The Company is exposed to foreign currency risk due to its operations in Japan (Yen). Assets and liabilities of the operations are re-measured into U.S. currency at exchange rates in effect at the balance sheet dates through the consolidated statements of comprehensive income. Gains or losses resulting from foreign currency transactions are re-measured using the rates on the dates on which those elements are recognized during the period and are included in other income or expense in the consolidated statements of operations. As of March 31, 2021, December 31, 2020 and December 31, 2019, the Company had foreign cash and cash equivalents of $444 thousand, $42 thousand and $55 thousand, respectively, which represented 4.7 percent, 0.3 percent and 1.9 percent, respectively, of total cash and cash equivalents. Concentrations of Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents. The Company is exposed to credit risk in the event of default by the financial institution holding its cash. The Company’s investment policy restricts investments to high-quality investments and limits the amounts invested with any one issuer, industry or geographic area. Risks associated with cash holdings in excess of insured limits are mitigated by banking with high-quality institutions. To date, the Company has not experienced any significant losses on its cash and cash equivalents. The Company periodically evaluates the relative credit standing of these financial institutions. The Company is subject to risks common in the power conversion components industry, including, but not limited to, technological obsolescence, dependence on key personnel, market acceptance of its products, the successful protection of its proprietary technologies, compliance with government regulations, and the possibility of not being able to obtain additional financing when needed. Comprehensive Loss Comprehensive loss is comprised of net loss and other comprehensive income (loss). Other comprehensive income (loss) includes the impact of foreign currency translation adjustments. Accounts Receivable Accounts receivable are analyzed and allowances for uncollectible accounts are recorded, as required. Provisions for uncollectible accounts, if any, are recorded as bad debt expense and included in general and administrative expenses in the accompanying consolidated statements of operations. The process for determining the appropriate level of allowances for doubtful accounts involves judgment, and the Company considers such factors as the age of the underlying receivables, historical and projected collection trends, the composition of outstanding receivables, current economic conditions and regulatory changes. An account is fully reserved when reasonable collection efforts have been unsuccessful and it is probable that the receivable will not be recovered. Recovery from doubtful accounts amounted to $48 thousand for the three months ended March 31, 2021. Provision for doubtful accounts amounted to $0 for the three months ended March 31, 2020 (unaudited), and $110 thousand and $0 for the years ended December 31, 2020 and 2019, respectively. Inventory Inventory is stated at the lower of cost (first-in, first-out method) or net realizable value. The Company periodically reviews the value of items in inventory and records write-downs or write-offs based on its assessment of slow moving or obsolete inventory. The Company maintains an inventory reserve for obsolete inventory and generally makes inventory value adjustments against the inventory reserve. Property and Equipment Property and equipment are stated at cost, net of accumulated depreciation and amortization. Depreciation is determined using the straight-line method over the estimated useful lives of the respective assets, generally ranging from three to seven years. Leasehold improvements are amortized on a straight-line basis over the shorter of their estimated useful lives or the related lease term. Depreciation for equipment commences once it is placed in service, and depreciation for buildings and leasehold improvements commences once they are ready for their intended use. The Company expenses maintenance and repair costs that do not extend the life of the asset as they are incurred. The Company evaluates the carrying amount of its property and equipment whenever events or changes in circumstances indicate that the assets may not be recoverable. An impairment loss would be recognized when estimated future cash flows expected to result from the use of an asset or asset group and its eventual disposition are less than the carrying amount of the asset or asset group. To date, there have been no such impairment losses. Goodwill Goodwill arose for the acquisition of a business in February 2014 based in Japan and was accounted for as the purchase of a business. Goodwill generated from business combinations and deemed to have indefinite lives are not subject to amortization and instead are tested for impairment at least annually in December unless certain events occur or circumstances change. Goodwill represents the excess of the purchase price over the fair value of the net assets and other identifiable intangible assets acquired. We test for goodwill impairment annually or earlier if events or changes in circumstances indicate goodwill might possibly be impaired. Impairment exists when the carrying value of the goodwill exceeds its implied fair value. An impairment loss would be recognized in an amount equal to that excess as a charge to operations in the consolidated statements of operations. For the three months ended March 31, 2021 and 2020 (unaudited), and the years ended December 31, 2020 and 2019, no impairment charge was recorded related to goodwill. Intangible Assets Intangible assets that are not considered to have an indefinite useful life are amortized over their estimated useful lives, which generally range from three to ten years. Each reporting period, the Company evaluates the estimated remaining useful lives of intangible assets and whether events or changes in circumstances warrant a revision to the remaining periods of amortization. If it is determined that the carrying values might not be recoverable based upon the existence of one or more indicators of impairment, the Company performs a test for recoverability using various methodologies, such as the income approach or cost approach, to determine the fair value of intangible assets depending upon the nature of the assets. If assets are considered to be impaired, the impairment to be recognized is measured as the amount by which the carrying amount of the assets exceeds their respective fair values. For the three months ended March 31, 2021 and 2020 (unaudited), and the years ended December 31, 2020 and 2019, no impairment charges were recorded related to intangible assets. Revenue Recognition The Company derives its revenues from sales of high-powered GaN-based products manufactured utilizing the Company’s proprietary and patented epiwafer technology and wafer fabrication and other assembly processes, sales of GaN epiwafers for the radio frequency (“RF”) and power markets, and sales of licenses to use such patented proprietary technology, as well as enabling EPI wafer growth services and products to our strategic partners. Revenues are recognized when control of these products or licenses are transferred to the Company’s customers in an amount that reflects the consideration it expects to be entitled to in exchange for those products and licenses. Sales and other taxes the Company collects concurrent with revenue-producing activities are excluded from revenue. Incidental items that are immaterial in the context of the contract are recognized as expense. The Company does not have any significant financing components associated with its revenue contracts, as payment is received at or shortly after the point of sale. Disaggregation of Revenue from Contracts with Customers Revenue consists of licensing revenue, government contract revenue from our contract with the U.S. Navy and product sales, with applicable performance obligations satisfied at a point in time. Products are sold to distributors and end-users in various sectors such as, but not limited to, the automotive, gaming, industrial, IT, and consumer products industries. As part of the Arrangement (Note 3 - Nexperia Arrangement) executed with Nexperia on April 4, 2018, the Company agreed to grant Nexperia the perpetual exclusive right to use the Company’s existing Gen-3 manufacturing process technology. License fees are received upon satisfaction of contractual milestones and recognized upon delivery of the perpetual license or transferred technology without any remaining performance obligations. For the year ended December 31, 2020, the Company recognized $5.0 million of licensing revenue. For the year ended December 31, 2019, the Company received the remaining $6.0 million and recognized a total of $9.0 million, including $3.0 million received in 2018, as licensing revenue upon satisfaction of contractual milestones and delivery of the perpetual license and transferred technology without any remaining performance obligations. In December 2020, we entered into a cooperation and development agreement with Yaskawa, pursuant to which Yaskawa agreed to provide $4.0 million over approximately three years to fund development activities related to industrial power conversion applications, with an initial focus on servo motor drive applications. Yaskawa provided $1.0 million of this $4.0 million commitment in December 2020. The Company evaluated and concluded that the deliverables are the same and nature of the services to be provided to Yaskawa will be consistent over the period of approximately three years. Accordingly, the Company recognized $333 thousand as revenue for the three months ended March 31, 2021 and the year ended December 31, 2020. As of March 31, 2021 and December 31, 2020, $334 thousand and $667 thousand, respectively, are included in deferred revenue on the consolidated balance sheet. Government contract revenues are principally generated under research and development contracts. Contract revenues are derived primarily from research contracts with agencies of the U.S. government. We believe credit risk related to accounts receivable arising from such contracts is minimal. These contracts may include cost-plus fixed fee and fixed price terms. All payments to us for work performed on contracts with agencies of the U.S. government are subject to adjustment upon audit by the Defense Contract Audit Agency. The Company received new government authorized rates for billing purposes which allowed for retroactive application since inception. The cumulative impact of this rate change was $423 thousand, of which $(83) thousand and $505 thousand were recorded in the three months ended March 31, 2021 and September 30, 2020, respectively. The Company will use the new approved rates on go-forward basis. Performance Obligations For performance obligations related to the sale of products, control transfers to the customer at a point in time. The Company’s principal terms of sale are free on board shipping or destination and the Company transfers control and records revenue for product sales upon shipment or delivery to the customer, respectively. For performance obligations related to the licensing of patented technology in perpetuity, control also transfers to the customer at a point in time. The Company transfers control and records revenue for licensing fees once the Company has (i) provided or otherwise makes available the patented technology to the customer and (ii) the customer is able to use and benefit from the patented technology. Variable Consideration The nature of the Company’s arrangement with Nexperia gives rise to variable consideration in the form of milestone and royalty payments. The royalties qualify for the sales and usage-based royalty exception, as the license of intellectual property is the predominant item to which the royalty relates and are recognized upon the subsequent sale occurring. The variable amounts are received upon satisfaction of contractually agreed upon development targets and sales volume. Research and Development The Company is a party to research grant contracts with the U.S. government for which the Company is reimbursed for specified costs incurred for its research projects. These projects include energy saving initiatives for which the U.S. government offers reimbursement funds. Such reimbursements are recorded as an offset to research and development expenses when the related qualified research and development expenses are incurred. Reimbursable costs are recognized in the same period the costs are incurred up to the limit of approved funding amounts on qualified expenses. Grant reimbursement of $42 thousand and $72 thousand was recorded as an offset to research and development expense for the three months ended March 31, 2021 and 2020 (unaudited), respectively, and grant reimbursement of $426 thousand and $0 was recorded as an offset to research and development expense for the years ended December 31, 2020 and 2019, respectively. Stock-Based Compensation All share-based payments, including grants of stock options, restricted stock awards (“RSAs”) and restricted stock units (“RSUs”), are measured at the fair value of the share-based awards on the grant date and recognized over their respective vesting periods, which is generally one to four years. The estimated fair value of stock options at the grant date is determined using the Black-Scholes-Merton pricing model. The RSAs and RSUs are measured using the estimated fair value of the stock price, which, due to limited trading history, is based on recent equity sales. The Company recognizes the fair value of share-based payments as compensation expense for all expected-to-vest stock-based awards over the vesting period of the award using the straight-line attribution or graded vesting method provided that the amount of compensation cost recognized at any date is no less than the portion of the grant-date fair value of the award that is vested at that date. The Black-Scholes-Merton option pricing model requires inputs such as the fair value of common stock on date of grant, expected term, expected volatility, dividend yield, and risk-free interest rate. Further, the forfeiture rate also affects the amount of aggregate compensation expense. These inputs are subjective and generally require significant analysis and judgment to develop. Volatility data is obtained from a study of publicly traded industry peer companies. The forfeiture rate is derived primarily from the Company’s historical data, and the risk-free interest rate is based on the yield available on U.S. Treasury zero-coupon issues commensurate with the expected term. Management generally uses the simplified method to calculate the expected term for employee grants as the Company has limited historical exercise data or alternative information to reasonably estimate an expected term assumption. The simplified method assumes that all options will be exercised midway between the weighted average vesting date and the contractual term of the option. Stock-based compensation expense recognized in the Company’s consolidated financial statements is based on awards that are expected to vest. These expense amounts have been reduced by using an estimated forfeiture rate. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The Company evaluates the assumptions used to estimate forfeitures annually in connection with the recognition of stock-based compensation expense. Loss Per Share Basic loss per share is calculated by dividing net loss applicable to common stockholders by the weighted average number of common shares outstanding during the period. Diluted loss per share is calculated by dividing the net loss attributable to common stockholders by the sum of the weighted average number of common shares outstanding plus potential dilutive common shares outstanding during the period. Potential dilutive securities, comprised of stock warrants, restricted stock units and stock options, are not reflected in diluted loss per share because such shares are anti–dilutive. Dilutive impact of potential common shares resulting from common stock equivalents is determined by applying the treasury stock method. For the three months ended March 31, 2021, there were 3,637,937 shares, consisting of 2,543,125 stock options, 935,397 restricted stock units and 159,415 stock warrants, that were not included in the computation of diluted loss per share because their effect would be anti-dilutive. For the three months ended March 31, 2020 (unaudited), there were 2,473,552 shares, consisting of 2,458,091 stock options and 15,461 stock warrants, that were not included in the computation of diluted loss per share because their effect would be anti-dilutive. For the year ended December 31, 2020, there were 3,285,058 shares, consisting of 2,320,318 stock options, 805,325 restricted stock units and 159,415 stock warrants, that were not included in the computation of diluted loss per share because their effect would be anti-dilutive. For the year ended December 31, 2019, there were 26,422,608 shares, consisting of 23,933,949 convertible preferred stocks, 2,473,198 stock options and 15,461 stock warrants, that were not included in the computation of diluted loss per share because their effect would be anti-dilutive. Fair Value Measurement Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The carrying values of the Company’s financial instruments such as cash equivalents, accounts receivable, revolving credit facility, accounts payable and accrued liabilities approximate fair values due to the short-term nature of these items. The Company has elected the fair value option for its promissory notes. Income Taxes The Company accounts for income taxes in accordance with Accounting Standards Codification (“ASC”) 740, Income Taxes (“ASC 740”). ASC 740 prescribes the use of the liability method. Deferred tax assets and liabilities are determined based on the difference between the financial statement carrying amounts and the tax basis of assets and liabilities and are measured using the enacted statutory tax rates in effect at the balance sheet date. The Company records a valuation allowance to reduce its deferred tax assets when uncertainty regarding their realizability exists. Equity Method Investments The Company uses the equity method to account for investments in entities that it does not control, but in which it has the ability to exercise significant influence over operating and financial policies. The Company's proportionate share of the net income or loss of these companies is included in consolidated net loss. Judgments regarding the level of influence over each equity method investment include consideration of key factors such as the Company's ownership interest, representation on the board of directors or other management body and participation in policy-making decisions. Segment Reporting The Company’s operations and its financial performance is evaluated on a consolidated basis by the chief operating decision maker. Accordingly, the Company considers all of its operations to be aggregated in one reportable operating segment. For the three months ended March 31, 2021, total revenue was $2.4 million, of which $2.0 million was from U.S. operations and $449 thousand was from Japan operations. For the three months ended March 31, 2020 (unaudited), total revenue was $1.1 million, of which $1.1 million was from U.S. operations and $11 thousand was from Japan operations. For the year ended December 31, 2020, total revenue was $11.4 million, of which $10.7 million was from U.S. operations and $713 thousand was from Japan operations. For the year ended December 31, 2019, total revenue was $11.9 million, of which $11.9 million was from U.S. operations and $28 thousand was from Japan operations. Recently Issued Accounting Standards under Evaluation Leases - In June 2020, the FASB issued ASU 2020-05, which amends the effective dates of the FASB’s standards on leasing (ASC 842) to give immediate relief to certain entities as a result of the widespread adverse economic effects and business disruptions caused by the COVID-19 pandemic. In February 2016, the FASB issued ASU 2016-02, Leases, which, for operating leases, requires the lessee to recognize a right-of-use asset and a lease liability, initially measured at the present value of the lease payments, on its balance sheet. The guidance also requires a lessee to recognize single lease costs, calculated so that the cost of the lease is allocated over the lease term, on a generally straight-line basis. The leasing standard’s effective dates were the fiscal year beginning after December 15, 2019 as originally issued (ASU 2016-02) and the fiscal year beginning after December 15, 2020 as amended by ASU 2019-10. As amended by ASU 2020-05, the leasing standard’s effective date is now the fiscal year beginning after December 15, 2021. The Company is currently evaluating the impact of this new standard on its consolidated financial statements and the adoption is not expected to have a significant impact on the consolidated financial statements. Financial Instruments - FASB ASU 2020-03, Codification Improvements to Financial Instruments, makes clear the determination of the contractual life of a net investment in leases in estimating expected credit losses under ASC 326, Financial Instruments – Credit Losses. In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). The standard changes the methodology for measuring credit losses on financial instruments and the timing of when such losses are recorded. ASU 2016-13 is effective for the Company in 2023. Early adoption is permitted. The Company is currently evaluating the impact of this new standard on its consolidated financial statements and the adoption is not expected to have a significant impact on the consolidated financial statements. Income Tax - In December 2019, the FASB issued ASU 2019-12, which modifies ASC 740 to simplify the accounting for income taxes. The ASU’s amendments are based on changes that were suggested by stakeholders as part of the FASB’s simplification initiative (i.e., the FASB’s effort to reduce the complexity of accounting standards while maintaining or enhancing the helpfulness of information provided to financial statement users). ASU 2019-12 is effective for fiscal years beginning after December 15, 2022. The Company is currently evaluating the impact of this new standard on its consolidated financial statements and the adoption is not expected to have a significant impact on the consolidated financial statements.

Nexperia Arrangement	3 Months Ended
Nexperia Arrangement	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nexperia Arrangement	Nexperia Arrangement Nexperia Transaction On April 4, 2018, the Company entered into a multi-element commercial arrangement with Nexperia B.V. (“Nexperia”) to obtain financing in exchange for the sale of equity instruments and performing certain technology and product development activities for Nexperia (collectively, the “Collaboration Arrangement”). Nexperia specializes in designing, manufacturing and selling a broad range of small discrete semiconductor devices that utilize components such as those manufactured by the Company. Financing under the Collaboration Arrangement is comprised of the following elements: •$16 million Series 3 preferred stock issuance •$9 million license fee for transfer of the Gen-3 manufacturing process •$5 million development loan, originally maturing March 31, 2020 and subsequently extended to June 30, 2020 intended to pre-fund the Gen-4 (Tranche A) technology development (the “Tranche A Loan”) •$10 million development loan maturing March 31, 2021 intended to pre-fund the Gen 5 and 1200V technology development (the “Tranche B Loan”) •$10 million revolving loan (the “Tranche C Loan”) The Company has to use the funds to operate the business in a manner consistent with or reasonably related to those business activities as carried out on or prior to April 4, 2018, the effective date of Collaboration Arrangement. In addition to the multiple elements outlined above, the Company and Nexperia entered into a Supply Agreement requiring that the Company be Nexperia’s primary supplier of specified components until June 30, 2020 on a best efforts basis. By entering into this Collaboration Arrangement, Nexperia will gain access to technology that allows for production of high power semiconductors for use in electric vehicles. On May 18, 2021, the term of the Supply Agreement was extended until December 31, 2025, with automatic one year renewals thereafter, and the Company may not terminate the Supply Agreement while the Option Agreement is in effect. Option Agreement was executed on May 18, 2021. See Note 18 - Subsequent Events. Further, Nexperia will obtain an exclusive license and market access to automotive customers outside of Japan and a sole license (non-exclusive of the Company), as well as market access to customers in other parts of the power market. Nexperia has a lien on certain of the Company’s U.S. patents not relating to metal organic chemical vapor deposition (“MOCVD”) or epiwafer technology, per the agreement. On March 31, 2019, the Company executed Amendment No. 1 to the Loan and Security Agreement (the ”LSA”), pursuant to which the Tranche B Loan was bifurcated into the following two separate sub-tranches: •$8 million development loan intended to pre-fund the Gen-5 (Tranche B) technology development (the “Tranche B Loan”) •$2 million development loan intended to pre-fund the 1200V technology development (the “Tranche B-1 Loan” and, together with the Tranche B Loan, the “Tranche B Loans”) On February 7, 2020, Amendment No. 2 to the LSA was executed to acknowledge the then-pending Merger, reaffirm the terms of the loans and confirm the waiver for the late delivery of the Company’s 2018 audited financial statements. On April 8, 2020, Amendment No. 3 to the LSA was executed to extend the maturity of the Tranche A Loan to April 30, 2020. On April 28, 2020, Amendment No. 4 to the LSA was executed to further extend the maturity of the Tranche A Loan to June 30, 2020. All other terms set forth under the original LSA remained unchanged following the amendments. The Tranche A and Tranche B Loans represent pre-funding for Gen-4 (Tranche A), Gen-5 (Tranche B), and 1200V (Tranche B-1) technology development for Nexperia. The specific development activities and associated performance milestones are contained within a Statement of Work (“SoW”) between the Company and Nexperia. The SoW may be modified from time to time based upon mutual business interests. This promise to perform the technology development is a good/service provided to a customer in exchange for consideration in the form of the technology development license fees that offset the Tranche A and Tranche B Loans outstanding. The Development Loans are recognized as a liability equal to the cash proceeds received. In relation to the license fee for the transfer of the Company’s Gen-3 manufacturing process to Nexperia, the Company received $3 million (the first of three tranches) in October 2018, $3 million (the second of three tranches) in April 2019, and $3 million (the third of three tranches) in October 2019. The Company recognized $9.0 million as licensing revenue during 2019 upon the completion of the transfer of the Company’s Gen-3 manufacturing process technology and mutual sign off between Nexperia and the Company. In January 2019, the Company received the $5 million Tranche A Loan. In June 2020, Nexperia agreed that the $5 million Tranche A Loan was permanently satisfied in full in connection with the Company transferring its Gen-4 technology development to Nexperia, at which point the Company recognized $5 million as licensing revenue. In June and July 2019, the Company received the $8 million Tranche B Loan. In December 2019, the Company received the $2 million Tranche B-1 Loan. The Company received the full $10 million Tranche C Loan under the credit facility during the year ended December 31, 2018. See Note 9 - Debts. On March 1, 2021, Amendment No. 5 to the LSA was executed to extend the maturity of the Tranche B loans of $10 million and the Tranche C Loan of $10 million to June 30, 2021 and May 18, 2021, respectively. All other terms set forth under the original LSA remained unchanged following the amendments. On May 18, 2021, Amendment No. 6 to the LSA was executed to (1) extend the maturity date for the Tranche C Loans to the earlier of April 4, 2023 and the occurrence of specified change of control events, (2) add Parent as a guarantor of Transphorm Technology, Inc.’s obligations under the Loan Agreement, and (3) convert the outstanding $2 million Tranche B-1 Loan into a Tranche C-1 Loan, which Tranche C-1 Loan has the same terms and conditions as the existing Tranche C Loan. See Note 18 - Subsequent Events.

Fair Value Measurements

3 Months Ended

Mar. 31, 2021

Fair Value Disclosures [Abstract]

Fair Value Measurements

FASB ASC 820, Fair Value Measurements and Disclosures, establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows:

Level 1 - Unadjusted quoted prices in active markets for identical assets and liabilities.

Level 2 - Inputs (other than quoted prices included within Level 1) that are observable, unadjusted quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data of substantially the full term of the related assets or liabilities.

Level 3 - Inputs reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date. Inputs are unobservable for the asset or liability. Consideration is given to the risk inherent in the valuation technique and the risk inherent in the inputs to the model.

The categorization of a financial instrument within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The following table summarizes the Company’s liabilities measured at fair value as of the dates presented, by level within the fair value hierarchy (in thousands):


	Level 1		Level 2		Level 3
March 31, 2021
Promissory note	$	—	$	—	$	16,128
December 31, 2020
Promissory note	$	—	$	—	$	15,392
December 31, 2019
Promissory note	$	—	$	—	$	16,169

The following table includes the changes in fair value of the promissory note which are Level 3 on the fair value hierarchy (in thousands):


January 1, 2019	$	15,852
Interest expense accrued	150
Increase in fair value	167
December 31, 2019	16,169
Interest expense accrued	150
Decrease in fair value	(927)
December 31, 2020	15,392
Interest expense accrued	37
Increase in fair value	699
March 31, 2021	$	16,128

The Company recorded interest expense of $37 thousand for each of the three months ended March 31, 2021 and 2020 (unaudited), and $150 thousand for each of the years ended December 31, 2020 and 2019. Fair value of promissory note increased $699 thousand for the three months ended March 31, 2021, and decreased $927 thousand and increased $167 thousand for the years ended December 31, 2020 and 2019, respectively.

There were no changes to our valuation techniques used to measure assets and liability fair values during the three months ended March 31, 2021 and 2020 (unaudited), and the years ended December 31, 2020 and 2019. The valuation techniques for the items in the table above are as follows:

Level 3 borrowings, which consist of a promissory note, are measured and reported at fair value using a Monte Carlo simulation valuation model. The models can include assumptions related to the value of the notes that are based on the estimated timing and amounts of future rounds of financing, including the estimated timing of a change in control of the Company, and estimated market interest rates, which represent significant unobservable inputs. Assumptions used are (1) the Company is worth today what it can generate in future cash to the Company, (2) cash received today is more than an equal amount of cash received in the future, and (3) future cash flows can be reasonably estimated. There were no transfers in or out of level 3 fair value instruments.

The following table summarizes assumptions used for fair value of promissory note for the periods presented:


	As of March 31, 2021	As of December 31,
		2020	2019
Stock price	$3.75	$3.00	$3.01
Time	1.5 years	1.75 years	0.25 years
Risk-free rate	0.12%	0.12%	1.55%
Volatility	50.6%	62.3%	38.2%

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Concentration of Credit Risk and Significant Customers

3 Months Ended

Mar. 31, 2021

Risks and Uncertainties [Abstract]

Concentration of Credit Risk and Significant Customers

The Company manages its credit risk associated with exposure to distributors and direct customers on outstanding accounts receivable through the application of credit approvals and other monitoring procedures. Credit sales, which are mainly on credit terms of 30 to 60 days, are only made to customers who meet the Company's credit standards, while sales to new customers or customers with low credit ratings are usually made on an advance payment basis. The Company closely monitors the aging of accounts receivable from its distributors and direct customers, and regularly reviews their financial positions, where available.

Significant customers are those that represent 10% or more of revenue or accounts receivable and are set forth in the following tables:


		As of March 31, 2021	As of December 31,
Accounts Receivable			2020	2019
Customer A		31.1%	49.3%	60.0%
Customer B		33.9%	31.9%	20.4%
Customer C		10.0%	*	*

	For the Three Months Ended March 31,		For the Year Ended December 31,
Revenue	2021	2020 (unaudited)	2020	2019
Customer A	27.3%	31.3%	59.6%	79.6%
Customer B	31.2%	53.2%	29.2%	13.3%

* Less than 10% of total

Customer A is a related party and Customer B is a government agency. See Note 17 - Related Party Transactions.

Inventory

3 Months Ended

Mar. 31, 2021

Inventory Disclosure [Abstract]

Inventory

Inventory consists of the following as of the dates presented (in thousands):


			December 31,
	March 31, 2021		2020		2019
Raw materials	$	626	$	633	$	412
Work in process	1,054		350		258
Finished goods	543		644		320
Total	$	2,223	$	1,627	$	990

An inventory write-off of $7 thousand and $169 thousand was recorded for the three months ended March 31, 2021 and 2020 (unaudited), respectively, and $435 thousand and $155 thousand was recorded for the years ended December 31, 2020 and 2019, respectively.

Property and Equipment

3 Months Ended

Mar. 31, 2021

Property, Plant and Equipment [Abstract]

Property and Equipment

Property and equipment as of the dates presented consists of the following (in thousands except years):


			December 31,				Estimated Useful Life (in years)
	March 31, 2021		2020		2019
Machinery and equipment	$	14,748	$	14,924	$	14,892	5
Computer equipment and software	836		828		876		3
Furniture and fixtures	185		189		186		7
Leasehold improvements (1)	4,959		4,970		4,954		7
Construction in progress	137		13		6
Property and equipment, gross	20,865		20,924		20,914
Less: accumulated depreciation and amortization	(19,505)		(19,600)		(19,144)
Property and equipment, net	$	1,360	$	1,324	$	1,770

(1) Leasehold improvements are amortized on a straight-line basis over the shorter of their estimated useful lives or the related remaining lease term.

The Company recorded depreciation and amortization expense related to property and equipment of $123 thousand and $133 thousand for the three months ended March 31, 2021 and 2020 (unaudited), respectively, and $509 thousand and $563 thousand for the years ended December 31, 2020 and 2019, respectively. The Company recognized $40 thousand as gain on sale of equipment in general and administrative expense for the three months ended March 31, 2021.

Intangible Assets

3 Months Ended

Mar. 31, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets

The carrying values of intangible assets as of the dates presented, respectively, consists of the following (in thousands except years):


	March 31, 2021
	Gross		Accumulated Amortization		Foreign Exchange Rate Changes		Net		Estimated Useful Life (in years)
Patents	$	2,963	$	(2,049)	$	—	$	914	10
Developed technology - 150V	560		(517)		(43)		—		6
Developed technology - 600V	1,701		(1,570)		(131)		—		6
Total	$	5,224	$	(4,136)	$	(174)	$	914

	December 31, 2020
	Gross		Accumulated Amortization		Foreign Exchange Rate Changes		Net		Estimated Useful Life (in years)
Patents	$	2,963	$	(1,975)	$	—	$	988	10
Developed technology - 150V	560		(555)		(5)		—		6
Developed technology - 600V	1,701		(1,684)		(17)		—		6
Total	$	5,224	$	(4,214)	$	(22)	$	988

	December 31, 2019
	Gross		Accumulated Amortization		Foreign Exchange Rate Changes		Net		Estimated Useful Life (in years)
Patents	$	2,963	$	(1,679)	$	—	$	1,284	10
Developed technology - 150V	560		(519)		(34)		7		6
Developed technology - 600V	1,701		(1,575)		(104)		22		6
Total	$	5,224	$	(3,773)	$	(138)	$	1,313

The Company recorded amortization expenses related to intangible assets of $74 thousand and $103 thousand for the three months ended March 31, 2021 and 2020 (unaudited), respectively, and $326 thousand and $653 thousand for the years ended December 31, 2020 and 2019, respectively.

Estimated future amortization expenses related to intangible assets as of March 31, 2021 were as follows (in thousands):


2022	$	296
2023	296
2024	296
2025	26
Thereafter	—
Total	$	914

Debts

3 Months Ended

Mar. 31, 2021

Debt Disclosure [Abstract]

Debts

Development Loans

On April 4, 2018, the Company entered into a Loan and Security Agreement (“LSA”) and Development and License Agreement (“DLA”) with Nexperia. The LSA provided for term loans in an aggregate principal amount of up to $15.0 million, which term loans were available in tranches (Tranche A, Tranche B and Tranche B-1) and subject to the satisfaction of specified conditions. The Tranche A Loan of $5.0 million initially was scheduled to mature on the earlier of the date a specified report is required to be delivered under the DLA or March 31, 2020. On April 8, 2020, the maturity of the Tranche A loan was extended to April 30, 2020 and, on April 28, 2020, the maturity of the Tranche A Loan was further extended to June 30, 2020. On June 29, 2020, the Tranche A Loan of $5.0 million was satisfied in full when the Company transferred its Gen-4 technology development to Nexperia. The Tranche B Loan of $8.0 million and Tranche B-1 Loan of $2.0 million mature on the earlier of the date a specified report is required to be delivered under the DLA or March 31, 2021, subject to extension as provided in the LSA. On March 1, 2021, the maturity of the Tranche B Loan of $8.0 million and Tranche B-1 Loan of $2.0 million was extended to June 30, 2021. On May 18, 2021, Tranche B-1 Loan of $2.0 million was converted into a Tranche C-1 Loan, which Tranche C-1 Loan has the same terms and conditions as the existing Tranche C Loan. See Note 3 - Nexperia Arrangement and Note 18 - Subsequent Events.

As of March 31, 2021, December 31, 2020 and December 31, 2019, aggregate principal amount of term loans outstanding under the LSA were $10.0 million, $10.0 million and $15.0 million, respectively.

Revolving Credit Facility

The LSA also provided a $10.0 million revolving loan (Tranche C Loan) that was scheduled to mature at the earlier of (i) April 3, 2021, and (ii) the date a Change of Control (as defined in the LSA) of the Company occurs. Interest payable by the Company accrues on the outstanding principal amount of the loans during such period at a rate of 6% per annum. The credit facility is secured against certain of our U.S. patents not relating to MOCVD or epiwafer technology. On March 1, 2021, the maturity of the Tranche C Loan of $10.0 million was extended to May 18, 2021. On May 18, 2021, the maturity of the Tranche C Loan was extended to the earlier of April 4, 2023 and the occurrence of specified change of control events. See Note 3 - Nexperia Arrangement and Note 18 - Subsequent Events.

The Tranche C Loan is recorded based on principal in the amount of $10.0 million and accrued interest (6% interest per annum). The Company recorded interest expense of $150 thousand and $152 thousand for the three months ended March 31, 2021 and 2020 (unaudited), respectively, and $610 thousand and $608 thousand for the years ended December 31, 2020 and 2019, respectively. The Company paid interest expense of $153 thousand and $0 for the three months ended March 31, 2021 and 2020 (unaudited), respectively, and $915 thousand and $496 thousand for the years ended December 31, 2020 and 2019, respectively. As of March 31, 2021, December 31, 2020 and December 31, 2019, the total balance of the revolving credit facility was $10.2 million, $10.2 million and $10.5 million, respectively.

Promissory Note

The Company’s stated value of promissory note obligation as of the dates presented consists of the following (in thousands):


					December 31,
	Interest Rate	Due Date	March 31, 2021		2020		2019
Yaskawa Note	1.00%	September 2022	$	15,523	$	15,486	$	15,336

Pursuant to ASC 825-10-15-4, the Company elected to apply the fair value option for the promissory note. As of the dates presented, the Company determined the fair value for the note, as compared to the face value, including accrued interest, as follows (in thousands):


			December 31,
	March 31, 2021		2020		2019
Yaskawa Note	$	16,128	$	15,392	$	16,169

Fair value of promissory note increased $699 thousand for the three months ended March 31, 2021, and decreased $927 thousand and increased $167 thousand for the years ended December 31, 2020 and 2019, respectively.

In October 2017, the Company issued an unsecured subordinated convertible promissory note to Yaskawa Electric Corporation (the “Yaskawa Note”) for $15.0 million. The stated interest rate of the Yaskawa Note is 1.0%, and principal plus interest is due on the earlier of September 30, 2022, or the date of the occurrence of an Event of Default, Change of Control or an Initial Public Offering (all terms as defined in the Yaskawa Note). In connection with the Merger, the Yaskawa Note was amended to be convertible at the option of the holder into a maximum of 3,076,171 shares of our common stock at a conversion price of $5.12 per share.

In connection with its promissory note obligation, the Company recorded interest expense of $37 thousand for each of the three months ended March 31, 2021 and 2020 (unaudited), and $150 thousand for each of the years ended December 31, 2020 and 2019. In accordance with the terms of the promissory note, interest is added to the principal balance and is reflected in the carrying value on the consolidated balance sheet. As of March 31, 2021, December 31, 2020 and December 31, 2019, accrued interest on the promissory note was $523 thousand, $486 thousand and $336 thousand, respectively.

In December 2020, we entered into a cooperation and development agreement with Yaskawa, pursuant to which Yaskawa agreed to provide $4.0 million over approximately three years to fund development activities related to industrial power conversion applications, with an initial focus on servo motor drive applications. Yaskawa provided $1.0 million of this $4.0 million commitment in December 2020. The Company evaluated and concluded that the deliverables are the same and nature of the services to be provided to Yaskawa will be consistent over the period of approximately three years. Accordingly, the Company recognized $333 thousand as revenue for the three months ended March 31, 2021 and for the year ended December 31, 2020. As of March 31, 2021 and December 31, 2020, $334 thousand and $667 thousand, respectively, is included in deferred revenue on the consolidated balance sheet.

As of March 31, 2021, the scheduled maturity on the development loans, revolving credit facility and promissory note was as follows (in thousands):


2022	$	20,150
2023	15,748
Thereafter	—
Total	$	35,898

Investment in Aizu Fujitsu Semiconductor Wafer Solution Limited ("AFSW")

3 Months Ended

Mar. 31, 2021

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Investment in Aizu Fujitsu Semiconductor Water Solution Limited ("AFSW")

Investment in Aizu Fujitsu Semiconductor Wafer Solution Limited (“AFSW”)

The Company has a 49% interest in AFSW and is a party to a joint venture agreement (the “JVA”) with Fujitsu Semiconductor Limited (“FSL”), the 51% owner of AFSW. AFSW manufactures semiconductor products exclusively for its owners under manufacturing agreements at prices estimated to cover the cost of production. AFSW was determined to be a variable interest entity (“VIE”) as the equity at risk was not believed to be sufficient. AFSW depends on its owners for any additional cash. The Company extended $1.0 million, $1.5 million, $7.3 million and $2.7 million to AFSW to fund AFSW’s operations for the three months ended March 31, 2021 and 2020, and the years ended December 31, 2020 and 2019, respectively. The Company’s known maximum exposure to loss approximated the carrying value of its investment balance, which included the financing. Potential future losses could be higher than the carrying amount of the Company’s investment, as we are liable, along with the other owner, for other future operating costs or obligations of AFSW. In addition, because Transphorm is currently committed to purchasing GaN wafers and production-related services from AFSW at pre-agreed pricing based upon the Company’s second generation products, the Company may be required to purchase products at a higher cost for its newer generation products. Unfunded commitment to AFSW was $1.9 million, $1.5 million and $1.7 million as of March 31, 2021, and December 31, 2020 and 2019, respectively.

On April 1, 2020, FSL exercised its put option under the JVA and notified us that FSL intended to exit the joint venture by selling its 51% interest in AFSW to us. Under the terms of the JVA, the aggregate purchase price for FSL’s interest in AFSW is expected to be one Japanese Yen. While the agreement provides that completion of the transaction was to take place as soon as 60 days from the date of the exercise notice, such transaction will be subject to regulatory and other approvals in Japan, which we believe will take up to June 30, 2021 to obtain, assuming such approval is received at all. In December 2020, we created a joint venture company in Singapore with a third party (controlling party with 75% ownership) to become a partner in AFSW, subject to regulatory and other approvals in Japan that we believe will take up to June 30, 2021 to obtain, assuming such approval is received at all. In addition, for at least one year following the date on which we (alone or with a third party) take over full ownership of AFSW, we have agreed to use our best efforts to maintain and continue the operations of AFSW, which is also synergistic with our own business for securing wafers for our products.

The Company’s investment activities in AFSW for the periods presented are summarized below (in thousands):


January 1, 2019	$	(659)
Investment	2,698
Loss	(3,703)
Effect of exchange rate change	(24)
December 31, 2019	(1,688)
Investment	7,348
Loss	(6,836)
Effect of exchange rate change	(290)
December 31, 2020	(1,466)
Investment	968
Loss	(1,468)
Effect of exchange rate change	100
March 31, 2021	$	(1,866)

Summarized financial information of AFSW for the periods indicated, as provided by the controlling owner, are as follows (in thousands):


			As of March 31, 2021		As of December 31,
					2020		2019
Current assets			$	932	$	1,503	$	3,733
Long-term assets			$	5,330	$	5,572	$	5,101
Other current liabilities			$	2,200	$	2,521	$	931
Due to controlling owner			$	22,354	$	22,136	$	17,913
Due to Transphorm			$	13,179	$	12,967	$	5,349
Net deficit			$	(31,471)	$	(30,549)	$	(15,359)

	For the Three Months Ended March 31,				For the Year Ended December 31,
	2021		2020 (unaudited)		2020		2019
Sales	$	842	$	1,248	$	2,976	$	11,599
Gross loss	$	(2,425)	$	(2,197)	$	(11,411)	$	(4,849)
Net loss	$	(2,995)	$	(2,895)	$	(13,952)	$	(7,557)

Commitments and Contingencies

3 Months Ended

Mar. 31, 2021

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Commitment with a Government Agency

In connection with a contract with a government agency, the Company entered into a commitment to acquire equipment and services from vendors totaling $7.4 million, all of which is reimbursable. The Company has made total purchases of $6.9 million cumulatively as of March 31, 2021, of which $6.9 million was reimbursed by the government agency as of March 31, 2021. During the three months ended March 31, 2021, the Company made purchases of $270 thousand and the remaining accounts payable to the vendors was $124 thousand as of March 31, 2021. During the year ended December 31, 2020, the Company made purchases of $6.2 million, of which $1.0 million was in accounts payable as of December 31, 2020.

Operating Leases

The Company leases office and fabrication space in Goleta, California, and office spaces in San Jose, California and in Japan under noncancelable operating lease agreements. The terms of certain leases provide for escalating rental payments through the term of the lease. The Company recognizes rent expense on a straight-line basis over the lease term and accrues for rent expense incurred but not paid.

As of March 31, 2021, future minimum operating lease commitments were as follows (in thousands):


2022	$	681
2023	322
2024	241
2025	60
Thereafter	—
Total	$	1,304

The Company recorded rent expense, net of rental income, which includes common area maintenance fees in addition to the base rent, of $212 thousand and $233 thousand for the three months ended March 31, 2021 and 2020 (unaudited), respectively, and of $892 thousand and $897 thousand for the years ended December 31, 2020 and 2019, respectively. Rental income from a noncancelable sublease was $30 thousand and $45 thousand for the three months ended March 31, 2021 and 2020 (unaudited), respectively, and $182 thousand for each of the years ended December 31, 2020 and 2019. As of March 31, 2021, there is no the future minimum rental payments to be received under the noncancelable sublease.

Contingencies

During the ordinary course of business, the Company may become a party to legal proceedings incidental to its business. The Company accrues contingent liabilities when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. Legal cost is expensed as incurred. The Company is not aware of any material legal claims or assessments. Although the results of litigation and claims are inherently unpredictable, management believes there was not at least a reasonable possibility that the Company had incurred a material loss with respect to any loss contingencies as of March 31, 2021 and through the issuance of these financial statements.

Indemnification

The Company from time to time enters into types of contracts that contingently require the Company to indemnify parties against third-party claims. These contracts primarily relate to: (1) real estate leases, under which the Company may be required to indemnify property owners for environmental and other liabilities and for other claims arising from the Company’s use of the applicable premises; (2) agreements with the Company’s officers, directors, and employees, under which the Company may be required to indemnify such persons from liabilities arising out of their relationship; (3) indemnifying customers in the event of product failure; and (4) agreements with outside parties that use the Company’s intellectual property, under which the Company may indemnify for copyright or patent infringement related specifically to the use of such intellectual property.

Historically, the Company has not been required to make payments under these obligations, and no liabilities have been recorded for these obligations in the Company’s consolidated financial statements.

Convertible Preferred Stock

3 Months Ended

Mar. 31, 2021

Equity [Abstract]

Convertible Preferred Stock

Convertible Preferred StockAs of December 31, 2019, the Company’s convertible preferred stock consisted of the following (in thousands, except share and per share data on a post conversion basis):


	Authorized Shares	Outstanding Shares	Carrying Value		Par Value per Share		Preference Value
Series 1	12,438,704	12,433,953	$	39,658	$	0.001	$	40,000
Series 2	7,507,699	7,499,996	$	30,000	$	0.001	$	30,000
Series 3	4,000,000	4,000,000	$	16,000	$	0.001	$	16,000
Total	23,946,403	23,933,949	$	85,658			$	86,000

Series 1 and 2 Preferred Stock

KKR Phorm Investors L.P. (Phorm) purchased 12,433,953 shares of Series 1 preferred stock, par value $0.001 per share, at a per share price of $3.217 for an aggregate purchase price of approximately $40 million. Phorm and other investors with a small percentage (~0.02%) purchased 7,499,996 shares of Series 2 preferred stock, par value $0.001 per share, at a per share price of $4.00 for an aggregate purchase price of approximately $30 million.

Series 3 Preferred Stock

On March 26, 2018, the Company entered into a stock purchase agreement and related contracts in order to effectuate the issuance of its Series 3 preferred stock to Nexperia. Pursuant to the terms of the stock purchase agreement, Nexperia purchased 4,000,000 shares of Series 3 preferred stock, par value $0.001 per share, at a per share price of $4.00, for an aggregate purchase price of approximately $16 million equating to a total ownership stake of approximately 9.9% on a fully-diluted basis. The Company has reserved shares of common stock, par value $0.001 per share, for issuance upon conversion of the Series 3 preferred stock (the conversion shares). The Series 3 preferred stock issued is substantially pari passu with the Company’s Series 1 and Series 2 preferred stock previously issued to Phorm with a small percentage (~0.02%) issued to other investors.

Each share of Series 1, Series 2 and Series 3 preferred stock are convertible at the option of the holder into such number of shares of common stock as is determined by dividing the original issue price (OIP) of the Series 1, Series 2 and Series 3 preferred stock by the conversion price in effect at the time of the conversion. The conversion price of the Series 1, Series 2 and Series 3 preferred stock is subject to adjustment for certain events. Each share of Series 1, Series 2 and Series 3 preferred stock automatically converts into common stock immediately upon the closing of an underwritten public offering of the Company’s common stock in which the aggregate net proceeds are at least $40 million and the offering price per share is not less than 1.5 times the OIP of the Series 1, Series 2 and Series 3 preferred stock (a Qualifying Public Offering).

The rights, privileges, and preferences of the Series 1, Series 2, and Series 3 convertible preferred stock are as follows:

Liquidation Rights - In the event of any liquidation, dissolution, or winding up of the Company, either voluntary or involuntary, the holders of convertible preferred stock will be entitled to receive, prior and in preference to any distribution of any assets of the Company to the holders of common stock, an amount per share equal to $3.217 per share for Series 1, $4.00 per share for Series 2 and $4.00 per share for Series 3, plus any declared but unpaid dividends. If, upon the occurrence of such an event, the assets and funds thus distributed among the holders of the convertible preferred stock are insufficient to permit the payment of the preferential amounts, the entire assets and funds legally available for distribution will be distributed ratably among the holders of convertible preferred stock in proportion to the full amount to which they would otherwise be respectively entitled. If, upon satisfaction of the convertible preferred stock preferences, there are any remaining assets and funds available for distribution, they will be ratably distributed among the holders of common stock.

Conversion - The convertible preferred stock is convertible at the option of the holder at any time into common stock on a one-for-one basis, subject to certain adjustments for anti-dilution. Each share of convertible preferred stock automatically converts into common stock in the event of an initial public offering (IPO) in which the proceeds are at least $40 million, net of the underwriting discount and commissions, and the offering price per

share is not less than 1.5 times the original issue price of the convertible preferred stock unless otherwise agreed to by the shareholders.

Dividends - The holders of convertible preferred stock are entitled to receive, out of funds legally available, cash dividends at the rate of $0.25736 per annum for Series 1, $0.32 per annum for Series 2 and $0.32 per annum for Series 3 on each outstanding share. Such dividends are payable when, as, and if declared by the Board of Directors and are noncumulative. Through December 31, 2019, no such dividends have been declared.

Voting - The holders of Series 1 convertible preferred stock shall be entitled to the number of votes equal to ten times the number of shares of common stock into which such shares could be converted, and the holders of Series 2 convertible preferred stock shall be entitled to the number of votes equal to the number of shares of common stock into which such shares could be converted. Each holder of Series 3 preferred stock shall be entitled to the number of votes equal to ten times the number of shares of common stock into which the shares of Series 3 preferred stock held by such holder could be converted as of the record date.

Due to certain provisions in liquidation and conversion rights the company has presented the convertible preferred stock outside of stockholders deficit as mezzanine equity.

The preferred stocks were converted to common stock upon the Merger. See Note 13 - Stockholders’ Deficit.

Stockholders' Deficit

3 Months Ended

Mar. 31, 2021

Equity [Abstract]

Stockholders' Deficit

Stockholders’ Deficit

On February 12, 2020, in connection with the Merger, shares of Transphorm Technology’s convertible preferred stock and common stock issued and outstanding immediately prior to the closing of the Merger were converted into shares of the Company’s common stock as follows:

•Series 1 convertible preferred stock: 51,680,254 shares issued and outstanding were converted into 12,433,953 shares issued and outstanding;

•Series 2 convertible preferred stock: 38,760,190 shares issued and outstanding were converted into 7,499,996 shares issued and outstanding;

•Series 3 convertible preferred stock: 31,850,304 issued and outstanding were converted into 4,000,000 shares issued and outstanding; and

•Common stock: 50,325,662 shares issued and outstanding were converted into 4,171,571 shares, net of 52,733 redeemed shares from unaccredited investors, issued and outstanding.

In addition, on February 12, 2020, the Company issued 1,650,000 shares in connection with the Merger with Peninsula Acquisition Corporation.

All per share and share amounts for all periods presented have been retroactively adjusted to reflect the effect of the Merger.

In December 2019, the Company amended its certificate of incorporation to authorize two classes of stock, to be designated, respectively, common stock and preferred stock. The total number of shares of stock that the Company shall have authority to issue is 755,000,000 shares, of which 750,000,000 shares are common stock, $0.0001 par value per share, and 5,000,000 shares are preferred stock, $0.0001 par value per share.

As of March 31, 2021, 750,000,000 shares of common stock are authorized, of which 40,531,996 shares of common stock were issued and outstanding and 5,000,000 shares of preferred stock are authorized, none of which were issued and outstanding. The Company’s Board of Directors has the ability to designate the rights, preferences and privileges for the preferred stock.

Private Placement

On February 12, 2020 and February 27, 2020, we sold an aggregate of 5,380,000 shares of common stock in a private placement offering at a purchase price of $4.00 per share, with aggregate gross proceeds of $21.5 million (before deducting placement agent fees and other offering expenses, which were an aggregate of $1.8 million).

On December 23, 2020, we sold an aggregate of 5,000,000 shares of common stock in a private placement offering at a purchase price of $3.00 per share and issued warrants to placement agents to purchase 150,000 shares of common stock at a price of $3.30 per share, with aggregate gross proceeds of $15.0 million (before deducting placement agent fees, financial advisor fees and other offering expenses, which were an aggregate of $1.4 million excluding warrant cost of $223 thousand).

On March 31, 2021, we sold 250,000 shares of common stock in a private placement offering at a purchase price of $4.00 per share, with gross proceed of $1.0 million (before deducting placement agent fees and other offering expenses, which were an aggregate of $50 thousand).

Common Stock

Common stockholders are entitled to dividends, as and when declared by the Company’s Board of Directors, subject to the priority dividend rights of the holders of other classes of stock. There have been no dividends declared to date. The holder of each share of common stock is entitled to one vote.

The Company has reserved shares of common stock for future issuance as of dates presented as follows:


			March 31, 2021
Equity incentive plans			5,039,025
Common stock warrants			159,415
Total			5,198,440

Common Stock Warrants

On December 23, 2020, we issued warrants to placement agent to purchase 150,000 shares of common stock at an exercise price of $3.30 per share in the private placement. Our warrants are exercisable by paying cash or by cashless exercise for unregistered shares of common stock. The exercise price of the warrants is subject to standard antidilutive provision adjustment in the case of stock dividends or other distributions on shares of common stock or any other equity or equity equivalent securities payable in shares of common stock, stock splits, stock combinations, reclassifications or similar events affecting our common stock, and also, subject to limitations, upon any distribution of assets, including cash, stock or other property to our stockholders. The exercise price of the warrants is not subject to “price-based” anti-dilution adjustment. We have determined that these warrants related to issuance of common stock are subject to equity treatment because the warrant holder has no right to demand cash settlement and there are no unusual anti-dilution rights.

The following warrants to purchase common stock were outstanding as of March 31, 2021:


Number of Shares	Exercise Price		Expiration Date
6,046	$	34.74	5 years after an initial public offering of the Company
3,369	$	54.41	5 years after an initial public offering of the Company
150,000	$	3.30	December 23, 2025
159,415

Stock Based Compensation

3 Months Ended

Mar. 31, 2021

Share-based Payment Arrangement [Abstract]

Stock Based Compensation

The 2020 Equity Incentive Plan (the “2020 Plan”) was approved by Transphorm Technology’s board of directors on February 10, 2020 and Transphorm Technology’s stockholders on February 12, 2020, and became effective on the business day immediately prior to the closing of the Merger. Our stockholders approved the 2020 Plan on February 11, 2020. We assumed the 2020 Plan in connection with the Merger. As of March 31, 2021, there were 1,560,503 shares available for grant and 935,397 restricted stock units outstanding under the 2020 Plan. The 2020 Plan provides for the grant of incentive stock options, within the meaning of Section 422 of the Internal Revenue Code of 1986, as amended (the “Code”), to our employees and our parent and subsidiary corporations’ employees, and for the grant of nonstatutory stock options, stock appreciation rights, restricted stock, restricted stock units (“RSUs”), performance units, and performance shares to our employees, directors, and consultants and our parent and subsidiary corporations’ employees and consultants.

Subject to the adjustment provisions of the 2020 Plan, and the automatic increase described in the 2020 Plan, the maximum aggregate number of shares of our common stock that may be issued under the 2020 Plan is 5,050,000 shares of our common stock, which includes (i) 2,588,077 shares initially reserved for issuance, plus (ii) any shares of our common stock subject to issued and outstanding awards under the 2007 Plan or 2015 Plan that were assumed in the Merger and that, on or after the closing of the Merger, expire or otherwise terminate without having been exercised or issued in full, are tendered to or withheld by us for payment of an exercise price or for tax withholding obligations, or are forfeited to or repurchased by us due to failure to vest, with the maximum number of shares to be added to the 2020 Plan pursuant to this clause (ii) equal to 2,461,923 shares. Subject to the adjustment provisions of the 2020 Plan, the number of shares of common stock available for issuance under the 2020 Plan will also include an annual increase on the first day of each fiscal year beginning with our 2022 fiscal year and ending on (and including) our 2030 fiscal year, in an amount equal to the least of: 5,000,000 shares of our common stock; five percent (5%) of the outstanding shares of our common stock on the last day of the immediately preceding fiscal year; or such number of shares of our common stock as the administrator of the 2020 Plan may determine.

Stock Options

The following table summarizes stock option activity and related information for the dates presented:


	Number of Options	Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Term (in Years)	Aggregate Intrinsic Value (1) (in thousands)
Outstanding at January 1, 2021	2,320,318	$	4.67	5.92	$	—
Options granted	223,638	$	6.37
Options exercised	(500)	$	3.14
Options canceled	(331)	$	9.29
Outstanding at March 31, 2021	2,543,125	$	4.82	6.05	$	—
Exercisable at March 31, 2021	2,283,243	$	4.70	5.65	$	—

Outstanding at January 1, 2020	2,473,198	$	4.67	6.84	$	—
Options granted	—	$	—
Options exercised	(6,821)	$	3.78
Options canceled	(146,059)	$	5.88
Outstanding at December 31, 2020	2,320,318	$	4.67	5.92	$	—
Exercisable at December 31, 2020	2,267,154	$	4.70	5.86	$	—

Outstanding at January 1, 2019	2,377,180	$	4.79	7.46	$	—
Options granted	209,908	$	3.14
Options exercised	(1,392)	$	3.86
Options canceled	(112,498)	$	4.34
Outstanding at December 31, 2019	2,473,198	$	4.67	6.84	$	—
Exercisable at December 31, 2019	2,079,809	$	4.95	6.65	$	—

(1) Intrinsic value represents the excess of the fair value on the last day of the period, which was $3.75, $3.00 and $3.01 as of March 31, 2021, December 31, 2020 and December 31, 2019, respectively, over the exercise price, multiplied by the number of options.

Stock-based compensation expense is determined based on the fair value of the Company’s common stock as determined by the Board of Directors and assumptions such as volatility, expected term, risk-free interest rates, and other factors. Changes in the deemed fair value of the common stock, the underlying assumptions in the calculations, the number of options granted or the terms of such options, the expected forfeiture rate, the treatment of tax benefits and other changes may result in significant differences in the amounts or timing of the compensation expense recognized. The assumptions and estimates are made as follows:

•Fair Value of Common Stock - The fair value of the shares of common stock underlying the stock options has been determined by the Board of Directors, utilizing valuation studies performed by third-party advisors. Because there has been no public market for the Company’s common stock, the Board of Directors has determined fair value of the common stock at the time of grant of the options by considering a number of objective and subjective factors, including valuations of comparable companies, sales of convertible preferred stock to unrelated third parties, operating and financial performance, the lack of liquidity of capital stock, and general and industry-specific economic outlook. The Company has not granted stock options with an exercise price that is less than the fair value of the underlying common stock as determined at the time of grant by the Board of Directors.

•Expected Volatility - The Company utilizes the historical volatility of representative public companies to determine its expected volatility, as there is no public trading of the Company’s common stock.

•Estimated Forfeitures - The Company adopted ASU 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting and has elected to account for forfeitures as they occur and therefore, stock-based compensation expense has been calculated based on actual forfeitures in the statements of operations, rather than our previous approach which was net of estimated forfeitures. The net cumulative effect of this change was not material.

•Expected Dividend Yield - The Company has not issued any common stock dividends; therefore, a dividend yield of zero was used.

•Risk-Free Interest Rate - The Company bases the risk-free interest rate used in the Black-Scholes-Merton option pricing model on the implied yield currently available on United States Treasury zero-coupon issues with an equivalent expected term.

•Expected Term - The expected term of stock options represents the period that the Company’s stock options are expected to be outstanding. The Company generally uses the simplified method to calculate the expected term for employee grants.

The assumptions used to value options granted to employees during the periods presented was as follows:


	Three Months Ended March 31, 2021	Year Ended December 31,
		2020	2019
Weighted average expected life (in years)	5.23	—	5.46
Risk-free interest rate	0.78% - 1.73%	—	1.34% - 1.94%
Expected volatility	43.1% - 44.3%	—	39.4% - 39.8%
Grant date fair market value	3.75		3.01
Grant date fair value	$0.94 - $1.65	—	$0.98 - $1.10
Dividend yield	—%	—	—%

Restricted Stock

Restricted Stock Awards

RSAs are grants of shares of our common stock that vest in accordance with terms and conditions established by the Company’s Board of Directors. Recipients of RSAs generally will have voting and dividend rights with respect to such shares upon grant without regard to vesting, unless the RSA agreement provides otherwise. Shares of restricted stock that do not vest are subject to forfeiture. In September 2020, we granted 123,501 RSAs outside of our 2020 Plan, 98,450 of which were fully vested on the date of grant and the remainder of which is scheduled to vest 120 days following the grant date. In December 2020, we granted 12,000 RSAs outside of our 2020 Plan, all of which were fully vested on the date of grant.

The following table summarizes RSA activity and related information for the periods presented:


	Number of Shares	Weighted-Average Grant Date Fair Value Per Share
January 1, 2020	—	$	—
Granted	135,501	$	3.91
Vested	(98,450)	$	3.88
December 31, 2020	37,051	$	4.00
Granted	—	$	—
Vested	(37,051)	$	4.00
March 31, 2021	—	$	—

Restricted Stock Units

RSUs are grants of shares of our common stock that vest in accordance with terms and conditions established by the administrator of the 2020 Plan. Subject to the provisions of the 2020 Plan, the administrator determines the terms and conditions of RSUs, including the vesting criteria. We granted 816,180 RSUs during the third quarter of 2020, 4,000 of which were fully vested on the date of grant. The remainder of the RSUs are scheduled to vest as follows: one third will vest on each of January 1, 2022, January 1, 2023 and July 1, 2023, in each case subject to the RSU holders’ continued status as a service provider to the Company through each vesting date. We granted 137,452 RSUs during the first quarter of 2021, which are scheduled to vest in various periods, beginning immediately and ending on February 2025, in each case subject to the RSU holders’ continued status as a service provider to the Company through each vesting date.

The following table summarizes RSU activity and related information for the periods presented:


	Number of Shares	Weighted-Average Grant Date Fair Value Per Share
January 1, 2020	—	$	—
Granted	816,180	$	4.00
Vested	(4,000)	$	4.00
Canceled	(6,855)	$	4.00
December 31, 2020	805,325	$	4.00
Granted	137,452	$	3.75
Vested	(3,000)	$	3.75
Canceled	(4,380)	$	4.00
March 31, 2021	935,397	$	3.96

Stock-Based Compensation

The accompanying consolidated statement of operations and comprehensive loss includes stock-based compensation expense for the periods presented as follows (in thousands):


	Three Months Ended March 31,				Year Ended December 31,
	2021		2020 (unaudited)		2020		2019
Cost of revenue	$	39	$	15	$	93	$	60
Research and development	115		46		306		196
Sales and marketing	33		7		68		30
General and administrative	326		64		1,058		280
Total	$	513	$	132	$	1,525	$	566

Unrecognized Stock-Based Compensation

Unrecognized stock-based compensation expense as of dates presented was as follows (in thousands):


	March 31, 2021			December 31, 2020			December 31, 2019
	Unrecognized Expense		Average Expected Recognition Period	Unrecognized Expense		Average Expected Recognition Period	Unrecognized Expense		Average Expected Recognition Period
Stock options	$	280	5.06 years	$	54	0.67 years	$	464	1.20 years
Restricted stock	2,738		1.76 years	2,687		1.87 years	—		—
Total	$	3,018	2.07 years	$	2,741	1.85 years	$	464	1.20 years

401(k) Savings Plan	3 Months Ended
401(k) Savings Plan	Mar. 31, 2021
Retirement Benefits [Abstract]
401(k) Savings Plan	401(k) Savings PlanThe Company has a 401(k) savings plan (the 401(k) plan). The 401(k) plan is a defined contribution plan intended to qualify under Section 401(k) of the Internal Revenue Code. All full-time employees of the Company are eligible to participate pursuant to the terms of the 401(k) plan. Contributions by the Company are discretionary, and the Company made no contributions during the three months ended March 31, 2021 and 2020 (unaudited), and the years ended December 31, 2020 and 2019.

- Definition

The entire disclosure for retirement benefits.

+ References

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+ Details

Income Taxes

3 Months Ended

Mar. 31, 2021

Income Tax Disclosure [Abstract]

Income Taxes

For the three months ended March 31, 2021, the Company reported a worldwide consolidated pretax loss of $6.6 million, which consisted of a pre-tax loss from U.S. operations of approximately $4.9 million and pre-tax loss from Japan operations of approximately $1.7 million. The pre-tax loss from Japan operations primarily consists of $1.5 million from Transphorm Aizu, Inc. with nominal pre-tax book loss from Transphorm Japan, Inc. and Transphorm Japan Epi, Inc.

For the year ended December 31, 2020, the Company reported a worldwide consolidated pretax loss of $17.9 million, which consisted of a pre-tax loss from U.S. operations of approximately $10.3 million and pre-tax loss from Japan operations of approximately $7.6 million. The pre-tax loss from Japan operations consists of $800 thousand from Transphorm Japan, Inc., a $6.8 million pre-tax loss from Transphorm Aizu, Inc. and $25 thousand pre-tax income from Transphorm Japan Epi, Inc.

For the year ended December 31, 2019, the Company reported a worldwide consolidated pre-tax loss of $15.3 million, which consisted of a pre-tax loss from U.S. operations of approximately $10.6 million and pre-tax loss from Japan operations of approximately $4.7 million. The pre-tax loss from Japan operations consists of $1.0 million from Transphorm Japan, Inc., a $3.7 million pre-tax loss from Transphorm Aizu, Inc. and $1 thousand pre-tax income from Transphorm Japan Epi, Inc.

There is no U.S. federal or foreign provision for income taxes because the Company has incurred operating losses since inception and is in a full valuation allowance position. For the three month ended March 31, 2021, and the years ended December 31, 2020 and 2019, the Company has recorded a state income tax provision of $1 thousand which represents minimum taxes. Deferred income taxes reflect the net tax effects of the net operating losses and the temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes.

Significant components of the Company’s deferred tax assets and deferred tax liabilities as of the dates presented as follows (in thousands):


			December 31,
	March 31, 2021		2020		2019
Deferred tax assets:
Net operating loss carryforwards	$	47,424	$	46,346	$	43,973
Tax credits	5,444		5,262		4,535
California capitalized research and development	72		80		343
Fixed assets	—		8		—
Others, net	581		593		602
Total deferred tax assets	53,521		52,289		49,453
Valuation allowance	(53,481)		(52,289)		(49,403)
Deferred tax asset, net of valuation allowance	40		—		50
Deferred tax liabilities:
Others, net	—		—		—
Fixed assets	(40)		—		(50)
Total deferred tax liabilities	(40)		—		(50)
Net deferred tax assets	$	—	$	—	$	—

As of March 31, 2021, December 31, 2020, and December 31, 2019, the Company had no assurance that future taxable income would be sufficient to fully utilize the net operating loss carryforwards and other deferred tax assets in the future. Consequently, the Company determined that a valuation allowance of approximately $53.5 million, $52.2 million and $49.4 million as of March 31, 2021, December 31, 2020, and December 31, 2019, respectively, was needed to offset the deferred tax assets resulting mainly from the net operating loss carryforwards.

The Company files income tax returns in the U.S. federal, California, and Oregon jurisdictions and is subject to U.S. federal, state, and local income tax examinations by tax authorities. Generally, the statute of limitations is 3 years for U.S. federal income tax and 4 years for state and local taxes. The statute of limitations may be extended for tax years where a corporation has a net operating loss carryforward or by agreement with the jurisdictional taxing authority. Accordingly, all of the Company's U.S. federal, state and local income tax years since inception remain open to examination by tax authorities. The Company is not currently under audit by any taxing authority.

The Company follows the provisions of uncertain tax positions as addressed in ASC 740-10. The Company recognized no increase or decrease in the liability for unrecognized tax benefits for any period presented. The Company recognizes interest accrued related to unrecognized tax benefits in interest expense and penalties in

operating expenses. No such interest or penalties were recognized during the period presented. The Company had no accruals for interest and penalties at March 31, 2021, December 31, 2020 and December 31, 2019.

The utilization of the Company’s net operating loss and tax credit carryforwards is dependent on the future profitability of the Company. Further, the Internal Revenue Code imposes substantial restrictions on the utilization of such carryforwards in the event of an ownership change of more than 50%, as defined, during any three-year period (Section 382 and 383 limitations). The Company has determined that several ownership changes have occurred, which have resulted in substantial limitations on the Company’s ability to utilize its pre-ownership change net operating loss and tax credit carryforwards. These substantial limitations are expected to result in both a permanent loss of certain tax benefits related to net operating loss carryforwards and federal research and development credits, as well as an annual utilization limitation. The Company performed an analysis through the APO and anticipates no further Section 382 and 383 limitations.

As of March 31, 2021, the Company has federal net operating loss carryforwards of $250.0 million, of which $207.5 million will begin to expire in 2027 unless previously utilized, and the Company has state net operating loss carryforwards of $153.5 million which will begin to expire in 2028 unless previously utilized. The Company also has foreign net operating loss carryforwards of approximately $5.4 million which will begin to expire in 2024. The federal net operating loss generated for the fiscal year ended March 31, 2021 of $4.5 million, December 31, 2020 of $10.5 million, December 31, 2019 of $8.8 million, and December 31, 2018 of $18.5 million can be carried forward indefinitely. However, the federal deduction for net operating losses incurred in tax years beginning after January 1, 2021 is limited to 80% annual taxable income. Under the Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”), the suspension of net operating losses generated in years 2018, 2019, and 2020 are not subject to the 80% limitation. The state net operating loss generated for the fiscal year ended March 31, 2021 of $1.0 million, December 31, 2020 of $2.6 million, and December 31, 2019 of $2.3 million can be carried forward 20 years.

As of March 31, 2021, the Company has federal research and development credit carryforwards of $4.6 million, which will begin to expire in 2032 unless previously utilized, and the Company had California research and development credit carryforwards of $4.2 million, which do not expire.

Deferred tax assets have not been established for net operating and tax credit carryforwards that are deemed to have no value due to the Section 382 and 383 limitations discussed above and, therefore, are not reflected in the table of deferred tax assets presented above. Future ownership changes, if any, may further limit the Company’s ability to utilize its remaining net operating losses and tax credit carryforwards. The Company performed an analysis as of March 31, 2021 and it was determined that no further limitations on tax attributes were required.

Reconciliation between federal statutory tax rate and the effective tax rate is shown in the following table for the periods presented:


	Three Months Ended March 31, 2021		Year Ended December 31,
			2020		2019
Federal statutory income tax rate	21.00	%	21.00	%	21.00	%
Research and development credit	2.73	%	4.06	%	4.76	%
Nondeductible expense	(2.43)	%	0.64	%	(3.18)	%
Loss in joint venture	(6.76)	%	(11.70)	%	(7.44)	%
Foreign income tax rate difference	2.45	%	4.10	%	2.99	%
Others, net	0.85	%	(2.08)	%	(0.75)	%
Valuation allowance	(17.84)	%	(16.02)	%	(17.38)	%
Effective tax rate	—	%	—	%	—	%

On March 27, 2020, the CARES Act was signed into law. The CARES Act repealed the 80% taxable income limitation for the 2018–2020 taxable years and reinstated NOL carrybacks for the 2018–2020 taxable years. In addition, the CARES Act temporarily increases the business interest deduction limitations from 30% to 50% of adjusted taxable income for the 2019 and 2020 taxable year. Lastly, a TCJA technical correction that classifies qualified improvement property as 15-year recovery period, allowing the bonus depreciation deduction to be claimed for such property retroactive as if it was included in the TCJA at the time of enactment. The Company does not anticipate a material impact to its December 31, 2019 financial statements due to the recent enactment.

On December 21, 2020, the Consolidated Appropriations Act (“CAA”) was signed into law. We do not expect any of the enactments of the CAA to have a material impact on the Company as of March 31, 2021.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References + Details

Related Party Transactions	3 Months Ended
Related Party Transactions	Mar. 31, 2021
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions During the three months ended March 31, 2021, the Company entered into the following related party transactions: •Recorded $406 thousand in cost of goods sold for services, recorded $144 thousand in research and development expense and incurred $9 thousand for employee and their benefits from the joint venture from AFSW; •Sold $12 thousand of products to non-controlling stockholders of the Company and incurred $54 thousand of license maintenance fee from a non-controlling stockholder of the Company; and •Recorded $357 thousand in license fee income, recorded $38 thousand of reimbursements in license maintenance fee, recorded $150 thousand in interest expense and sold $304 thousand of products to a stockholder and noteholder of the Company. See Note 3 - Nexperia Arrangement. As of March 31, 2021, total due from related parties was $14.1 million, consisting of $13.5 million due from the AFSW joint venture, $5 thousand accounts receivable from non-controlling stockholders of the Company, and $503 thousand accounts receivable from a stockholder and noteholder of the Company. As of March 31, 2021, total accounts payable to related parties was $370 thousand to the AFSW joint venture and $11 thousand to Nexperia, and accrued royalty was $4 thousand to Furukawa. During the three months ended March 31, 2020 (unaudited), the Company entered into the following related party transactions: •Recorded $111 thousand in cost of goods sold for services, recorded research and development expense of $245 thousand, of which $177 thousand was reimbursable, recorded $84 thousand in other expense for commitment for services, and received reimbursement of payroll related costs of $14 thousand from the joint venture with AFSW; •Sold $13 thousand of products to non-controlling stockholders of the Company and incurred $50 thousand of license maintenance fee from a non-controlling stockholder of the Company; and •Recorded $37 thousand in license fee income, recorded $152 thousand in interest expense, recorded $177 thousand reimbursement for research and development, and sold $344 thousand of products to a stockholder and noteholder of the Company. See Note 3 - Nexperia Arrangement. During the year ended December 31, 2020, the Company entered into the following related party transactions: •Recorded $241 thousand in cost of goods sold for services, recorded research and development expense of $919 thousand, of which $408 thousand was reimbursable and recorded $84 thousand in other expense for commitment for services from the AFSW joint venture; •Sold $165 thousand of products to non-controlling stockholders of the Company and incurred $200 thousand of license maintenance fee from a non-controlling stockholder of the Company; and •Recorded $5.2 million in license fee income, recorded $701 thousand in EPI Gen 4 wafer growth sales, recorded $150 thousand of reimbursements in license maintenance fee, recorded $610 thousand in interest expense, recorded $408 thousand reimbursement for research and development, and sold $915 thousand of products to a stockholder and noteholder of the Company. See Note 3 - Nexperia Arrangement. As of December 31, 2020, total due from related parties was $13.9 million, consisting of $13.5 million due from the AFSW joint venture, $17 thousand accounts receivable from non-controlling stockholders of the Company, and $435 thousand accounts receivable from a stockholder and noteholder of the Company. As of December 31, 2020, total accounts payable to related parties was $512 thousand to the AFSW joint venture and $24 thousand to Nexperia, and accrued royalty was $100 thousand to Furukawa. During the year ended December 31, 2019, the Company entered into the following related party transactions: •Recorded $211 thousand in cost of goods sold for services, recorded research and development expense of $695 thousand, of which $195 thousand was reimbursable, recorded $444 thousand in other expense for commitment for services, and incurred $14 thousand for employees and their benefits seconded from the AFSW joint venture; •Sold $241 thousand of products to non-controlling stockholders of the Company, incurred $200 thousand of license maintenance fee to a non-controlling stockholder, and incurred $21 thousand for employees and their related benefits seconded from a non-controlling stockholder of the Company; and •Recorded $9.2 million in license fee revenue, recorded $195 thousand reimbursement for research and development, recorded $608 thousand in interest expense and sold $504 thousand of products to a stockholder and noteholder of the Company. See Note 3 - Nexperia Arrangement. As of December 31, 2019, total due from related parties was $5.8 million, consisting of $5.3 million due from the AFSW joint venture, $38 thousand accounts receivable from non-controlling stockholders of the Company and $426 thousand accounts receivable from a stockholder and noteholder of the Company. As of December 31, 2019, total accounts payable due to related parties was $272 thousand to non-controlling stockholders of the Company.

Subsequent Events	3 Months Ended
Subsequent Events	Mar. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On May 18, 2021, the “Company entered into a series of agreements with Nexperia, as described below. These included two new agreements (a strategic cooperation agreement and an option agreement), as well as amendments to the Company’s existing loan and security agreement, development and license agreement, and supply agreement with Nexperia. Strategic Cooperation Agreement The strategic cooperation agreement serves as a framework agreement that describes the numerous agreements between the parties and provides Nexperia with information rights and inspection rights with respect to the Company’s business. Option Agreement The option agreement establishes the parameters pursuant to which Nexperia, in certain limited instances, is permitted to exercise an option (the “Option”) to acquire Transphorm Japan Epi, Inc. (“TJE”), a Japanese subsidiary of the Company through which the Company is engaged in the development, manufacturing and sales of gallium nitride (“GaN”) based epitaxial wafer products. In general, the Option is exercisable upon (1) certain acquisitions of securities or assets of the Company or its subsidiaries by a Competitor (as defined in the option agreement) that results in the Company, directly or indirectly, owning less than a majority of TJE, which acquisition is followed by any material breach (that is not cured within a specified time period) by the Company or a subsidiary of its obligations with respect to epiwafer supply to Nexperia under the Company’s amended and restated supply agreement (the “Supply Agreement”) with Nexperia, or (2) the unilateral termination by the Company of the Supply Agreement. The option agreement also establishes the material terms, including price and timing, for the exercise of the Option by Nexperia. The Option terminates (1) if the Option is not exercised by Nexperia prior to the date on which the option agreement terminates, or (2) on the first to occur of (a) the termination of the option agreement upon written agreement of the parties, (b) the mutual termination or expiration of the Supply Agreement, or (c) the first to occur of (i) two years following the date on which the Company notifies Nexperia of epiwafer qualification of a second source and (ii) April 1, 2028. In connection with the option agreement, the Company has also amended and restated its existing intracompany license agreement with TJE to clarify Nexperia’s rights upon exercise of the Option. Amendment to Loan and Security Agreement Transphorm Technology, Inc. (“Borrower”) is party to that certain Loan and Security Agreement, dated as of April 4, 2018, between Borrower and Nexperia as lender (as amended, the “Loan Agreement”). The Company and Nexperia entered into Amendment No. 6 to the Loan Agreement, pursuant to which the Loan Agreement was amended to (1) extend the maturity date for the Tranche C Loans (as defined in the Loan Agreement) to the earlier of April 4, 2023 and the occurrence of specified change of control events, (2) add the Company as a guarantor of Borrower’s obligations under the Loan Agreement, and (3) convert the outstanding $2.0 million Tranche B-1 Loan (as defined in the Loan Agreement) into a Tranche C-1 Loan, which Tranche C-1 Loan has the same terms and conditions as the existing Tranche C Loans. Amended and Restated Development and License Agreement The Company entered into an amended and restated development and license agreement (the “DLA”) with Nexperia, pursuant to which the Company agreed to develop and transfer to Nexperia certain manufacturing process technologies to enable Nexperia to manufacture GaN-based products at Nexperia’s facilities. These technologies to be transferred included the Company’s Gen-3, Gen-4 (Tranche A), and Gen-5 (Tranche B) process technologies, but do not include the Company’s Epi Process Technology (as defined in the DLA). Nexperia also agreed to provide funding for the development of such technologies in return for limited exclusivities in automotive and other fields. Nexperia’s rights now include sale of products in the automotive field in Japan along with Transphorm’s rights for sale of products in the automotive field in Japan which remain in place. As per the original agreement, after April 2023, Nexperia’s exclusive rights for sale of products in the automotive field outside of Japan terminate. In addition, the parties have clarified the ability of Nexperia’s customers to use products developed by Nexperia through exercise of its rights under this agreement. Amended and Restated Supply Agreement The Company entered into the Supply Agreement with Nexperia, which sets forth the terms under which Nexperia may purchase epiwafers and processed wafers from the Company, and the Company may purchase processed wafers from Nexperia. The agreement specifies that Nexperia is the Company’s priority customer with respect to epiwafers manufactured by TJE and, accordingly, has preferred utilization of extra capacity, and further specifies procedures to address expansion of the Company’s epiwafer manufacturing capacity and Nexperia’s obligations with respect thereto. The term of the Supply Agreement was extended until December 31, 2025, with automatic one year renewals thereafter, and the Company may not terminate the Supply Agreement while the option agreement is in effect.

Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2021
Accounting Policies [Abstract]
Principles of Consolidation	The consolidated financial statements include the accounts of the Parent and its wholly-owned subsidiaries, Transphorm Technology, Transphorm Japan, Inc., Transphorm Japan Epi, Inc. and Transphorm Aizu, Inc. Upon consolidation, all significant intercompany accounts and transactions have been eliminated.
Use of Estimates	The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Management bases its estimates and assumptions on historical experience, knowledge of current conditions, and its belief of what could occur in the future, given available information. Actual results could differ from those estimates, and such differences could be material to the consolidated financial statements. Estimates are used for, but not limited to, the determinations of fair value of stock awards and promissory notes, accrual of liabilities, revenue recognition, inventory reserve, and useful lives for property and equipment.
Cash and Cash Equivalents	The Company considers all highly-liquid investments with original maturities of 90 days or less at the date of purchase to be cash equivalents. Cash and cash equivalents consist principally of bank deposits and money market funds.
Foreign Currency Risk	The Company is exposed to foreign currency risk due to its operations in Japan (Yen). Assets and liabilities of the operations are re-measured into U.S. currency at exchange rates in effect at the balance sheet dates through the consolidated statements of comprehensive income. Gains or losses resulting from foreign currency transactions are re-measured using the rates on the dates on which those elements are recognized during the period and are included in other income or expense in the consolidated statements of operations.
Concentrations of Risk	Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents. The Company is exposed to credit risk in the event of default by the financial institution holding its cash. The Company’s investment policy restricts investments to high-quality investments and limits the amounts invested with any one issuer, industry or geographic area. Risks associated with cash holdings in excess of insured limits are mitigated by banking with high-quality institutions. To date, the Company has not experienced any significant losses on its cash and cash equivalents. The Company periodically evaluates the relative credit standing of these financial institutions. The Company is subject to risks common in the power conversion components industry, including, but not limited to, technological obsolescence, dependence on key personnel, market acceptance of its products, the successful protection of its proprietary technologies, compliance with government regulations, and the possibility of not being able to obtain additional financing when needed.
Comprehensive Loss	Comprehensive loss is comprised of net loss and other comprehensive income (loss). Other comprehensive income (loss) includes the impact of foreign currency translation adjustments.
Accounts Receivable	Accounts receivable are analyzed and allowances for uncollectible accounts are recorded, as required. Provisions for uncollectible accounts, if any, are recorded as bad debt expense and included in general and administrative expenses in the accompanying consolidated statements of operations. The process for determining the appropriate level of allowances for doubtful accounts involves judgment, and the Company considers such factors as the age of the underlying receivables, historical and projected collection trends, the composition of outstanding receivables, current economic conditions and regulatory changes. An account is fully reserved when reasonable collection efforts have been unsuccessful and it is probable that the receivable will not be recovered.
Inventory	Inventory is stated at the lower of cost (first-in, first-out method) or net realizable value. The Company periodically reviews the value of items in inventory and records write-downs or write-offs based on its assessment of slow moving or obsolete inventory. The Company maintains an inventory reserve for obsolete inventory and generally makes inventory value adjustments against the inventory reserve.
Property and Equipment	Property and equipment are stated at cost, net of accumulated depreciation and amortization. Depreciation is determined using the straight-line method over the estimated useful lives of the respective assets, generally ranging from three to seven years. Leasehold improvements are amortized on a straight-line basis over the shorter of their estimated useful lives or the related lease term. Depreciation for equipment commences once it is placed in service, and depreciation for buildings and leasehold improvements commences once they are ready for their intended use. The Company expenses maintenance and repair costs that do not extend the life of the asset as they are incurred.
Property and Equipment, Impairment	The Company evaluates the carrying amount of its property and equipment whenever events or changes in circumstances indicate that the assets may not be recoverable. An impairment loss would be recognized when estimated future cash flows expected to result from the use of an asset or asset group and its eventual disposition are less than the carrying amount of the asset or asset group.
Goodwill	Goodwill arose for the acquisition of a business in February 2014 based in Japan and was accounted for as the purchase of a business. Goodwill generated from business combinations and deemed to have indefinite lives are not subject to amortization and instead are tested for impairment at least annually in December unless certain events occur or circumstances change. Goodwill represents the excess of the purchase price over the fair value of the net assets and other identifiable intangible assets acquired. We test for goodwill impairment annually or earlier if events or changes in circumstances indicate goodwill might possibly be impaired. Impairment exists when the carrying value of the goodwill exceeds its implied fair value. An impairment loss would be recognized in an amount equal to that excess as a charge to operations in the consolidated statements of operations.
Intangible Assets	Intangible assets that are not considered to have an indefinite useful life are amortized over their estimated useful lives, which generally range from three to ten years. Each reporting period, the Company evaluates the estimated remaining useful lives of intangible assets and whether events or changes in circumstances warrant a revision to the remaining periods of amortization.If it is determined that the carrying values might not be recoverable based upon the existence of one or more indicators of impairment, the Company performs a test for recoverability using various methodologies, such as the income approach or cost approach, to determine the fair value of intangible assets depending upon the nature of the assets. If assets are considered to be impaired, the impairment to be recognized is measured as the amount by which the carrying amount of the assets exceeds their respective fair values.
Revenue Recognition	The Company derives its revenues from sales of high-powered GaN-based products manufactured utilizing the Company’s proprietary and patented epiwafer technology and wafer fabrication and other assembly processes, sales of GaN epiwafers for the radio frequency (“RF”) and power markets, and sales of licenses to use such patented proprietary technology, as well as enabling EPI wafer growth services and products to our strategic partners. Revenues are recognized when control of these products or licenses are transferred to the Company’s customers in an amount that reflects the consideration it expects to be entitled to in exchange for those products and licenses. Sales and other taxes the Company collects concurrent with revenue-producing activities are excluded from revenue. Incidental items that are immaterial in the context of the contract are recognized as expense. The Company does not have any significant financing components associated with its revenue contracts, as payment is received at or shortly after the point of sale. Disaggregation of Revenue from Contracts with Customers Revenue consists of licensing revenue, government contract revenue from our contract with the U.S. Navy and product sales, with applicable performance obligations satisfied at a point in time. Products are sold to distributors and end-users in various sectors such as, but not limited to, the automotive, gaming, industrial, IT, and consumer products industries. As part of the Arrangement (Note 3 - Nexperia Arrangement) executed with Nexperia on April 4, 2018, the Company agreed to grant Nexperia the perpetual exclusive right to use the Company’s existing Gen-3 manufacturing process technology. License fees are received upon satisfaction of contractual milestones and recognized upon delivery of the perpetual license or transferred technology without any remaining performance obligations. For the year ended December 31, 2020, the Company recognized $5.0 million of licensing revenue. For the year ended December 31, 2019, the Company received the remaining $6.0 million and recognized a total of $9.0 million, including $3.0 million received in 2018, as licensing revenue upon satisfaction of contractual milestones and delivery of the perpetual license and transferred technology without any remaining performance obligations. In December 2020, we entered into a cooperation and development agreement with Yaskawa, pursuant to which Yaskawa agreed to provide $4.0 million over approximately three years to fund development activities related to industrial power conversion applications, with an initial focus on servo motor drive applications. Yaskawa provided $1.0 million of this $4.0 million commitment in December 2020. The Company evaluated and concluded that the deliverables are the same and nature of the services to be provided to Yaskawa will be consistent over the period of approximately three years. Accordingly, the Company recognized $333 thousand as revenue for the three months ended March 31, 2021 and the year ended December 31, 2020. As of March 31, 2021 and December 31, 2020, $334 thousand and $667 thousand, respectively, are included in deferred revenue on the consolidated balance sheet. Government contract revenues are principally generated under research and development contracts. Contract revenues are derived primarily from research contracts with agencies of the U.S. government. We believe credit risk related to accounts receivable arising from such contracts is minimal. These contracts may include cost-plus fixed fee and fixed price terms. All payments to us for work performed on contracts with agencies of the U.S. government are subject to adjustment upon audit by the Defense Contract Audit Agency. The Company received new government authorized rates for billing purposes which allowed for retroactive application since inception. The cumulative impact of this rate change was $423 thousand, of which $(83) thousand and $505 thousand were recorded in the three months ended March 31, 2021 and September 30, 2020, respectively. The Company will use the new approved rates on go-forward basis. Performance Obligations For performance obligations related to the sale of products, control transfers to the customer at a point in time. The Company’s principal terms of sale are free on board shipping or destination and the Company transfers control and records revenue for product sales upon shipment or delivery to the customer, respectively. For performance obligations related to the licensing of patented technology in perpetuity, control also transfers to the customer at a point in time. The Company transfers control and records revenue for licensing fees once the Company has (i) provided or otherwise makes available the patented technology to the customer and (ii) the customer is able to use and benefit from the patented technology. Variable Consideration The nature of the Company’s arrangement with Nexperia gives rise to variable consideration in the form of milestone and royalty payments. The royalties qualify for the sales and usage-based royalty exception, as the license of intellectual property is the predominant item to which the royalty relates and are recognized upon the subsequent sale occurring. The variable amounts are received upon satisfaction of contractually agreed upon development targets and sales volume.
Research and Development	The Company is a party to research grant contracts with the U.S. government for which the Company is reimbursed for specified costs incurred for its research projects. These projects include energy saving initiatives for which the U.S. government offers reimbursement funds. Such reimbursements are recorded as an offset to research and development expenses when the related qualified research and development expenses are incurred. Reimbursable costs are recognized in the same period the costs are incurred up to the limit of approved funding amounts on qualified expenses.
Stock-Based Compensation	All share-based payments, including grants of stock options, restricted stock awards (“RSAs”) and restricted stock units (“RSUs”), are measured at the fair value of the share-based awards on the grant date and recognized over their respective vesting periods, which is generally one to four years. The estimated fair value of stock options at the grant date is determined using the Black-Scholes-Merton pricing model. The RSAs and RSUs are measured using the estimated fair value of the stock price, which, due to limited trading history, is based on recent equity sales. The Company recognizes the fair value of share-based payments as compensation expense for all expected-to-vest stock-based awards over the vesting period of the award using the straight-line attribution or graded vesting method provided that the amount of compensation cost recognized at any date is no less than the portion of the grant-date fair value of the award that is vested at that date. The Black-Scholes-Merton option pricing model requires inputs such as the fair value of common stock on date of grant, expected term, expected volatility, dividend yield, and risk-free interest rate. Further, the forfeiture rate also affects the amount of aggregate compensation expense. These inputs are subjective and generally require significant analysis and judgment to develop. Volatility data is obtained from a study of publicly traded industry peer companies. The forfeiture rate is derived primarily from the Company’s historical data, and the risk-free interest rate is based on the yield available on U.S. Treasury zero-coupon issues commensurate with the expected term. Management generally uses the simplified method to calculate the expected term for employee grants as the Company has limited historical exercise data or alternative information to reasonably estimate an expected term assumption. The simplified method assumes that all options will be exercised midway between the weighted average vesting date and the contractual term of the option. Stock-based compensation expense recognized in the Company’s consolidated financial statements is based on awards that are expected to vest. These expense amounts have been reduced by using an estimated forfeiture rate. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The Company evaluates the assumptions used to estimate forfeitures annually in connection with the recognition of stock-based compensation expense.
Loss Per Share	Basic loss per share is calculated by dividing net loss applicable to common stockholders by the weighted average number of common shares outstanding during the period. Diluted loss per share is calculated by dividing the net loss attributable to common stockholders by the sum of the weighted average number of common shares outstanding plus potential dilutive common shares outstanding during the period. Potential dilutive securities, comprised of stock warrants, restricted stock units and stock options, are not reflected in diluted loss per share because such shares are anti–dilutive. Dilutive impact of potential common shares resulting from common stock equivalents is determined by applying the treasury stock method.
Fair Value Measurement	Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The carrying values of the Company’s financial instruments such as cash equivalents, accounts receivable, revolving credit facility, accounts payable and accrued liabilities approximate fair values due to the short-term nature of these items. The Company has elected the fair value option for its promissory notes.
Income Taxes	The Company accounts for income taxes in accordance with Accounting Standards Codification (“ASC”) 740, Income Taxes (“ASC 740”). ASC 740 prescribes the use of the liability method. Deferred tax assets and liabilities are determined based on the difference between the financial statement carrying amounts and the tax basis of assets and liabilities and are measured using the enacted statutory tax rates in effect at the balance sheet date. The Company records a valuation allowance to reduce its deferred tax assets when uncertainty regarding their realizability exists.
Equity Method Investments	The Company uses the equity method to account for investments in entities that it does not control, but in which it has the ability to exercise significant influence over operating and financial policies. The Company's proportionate share of the net income or loss of these companies is included in consolidated net loss. Judgments regarding the level of influence over each equity method investment include consideration of key factors such as the Company's ownership interest, representation on the board of directors or other management body and participation in policy-making decisions.
Segment Reporting	The Company’s operations and its financial performance is evaluated on a consolidated basis by the chief operating decision maker. Accordingly, the Company considers all of its operations to be aggregated in one reportable operating segment.
Recently Issued Accounting Standards Adopted and under Evaluation	Recently Issued Accounting Standards under Evaluation Leases - In June 2020, the FASB issued ASU 2020-05, which amends the effective dates of the FASB’s standards on leasing (ASC 842) to give immediate relief to certain entities as a result of the widespread adverse economic effects and business disruptions caused by the COVID-19 pandemic. In February 2016, the FASB issued ASU 2016-02, Leases, which, for operating leases, requires the lessee to recognize a right-of-use asset and a lease liability, initially measured at the present value of the lease payments, on its balance sheet. The guidance also requires a lessee to recognize single lease costs, calculated so that the cost of the lease is allocated over the lease term, on a generally straight-line basis. The leasing standard’s effective dates were the fiscal year beginning after December 15, 2019 as originally issued (ASU 2016-02) and the fiscal year beginning after December 15, 2020 as amended by ASU 2019-10. As amended by ASU 2020-05, the leasing standard’s effective date is now the fiscal year beginning after December 15, 2021. The Company is currently evaluating the impact of this new standard on its consolidated financial statements and the adoption is not expected to have a significant impact on the consolidated financial statements. Financial Instruments - FASB ASU 2020-03, Codification Improvements to Financial Instruments, makes clear the determination of the contractual life of a net investment in leases in estimating expected credit losses under ASC 326, Financial Instruments – Credit Losses. In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). The standard changes the methodology for measuring credit losses on financial instruments and the timing of when such losses are recorded. ASU 2016-13 is effective for the Company in 2023. Early adoption is permitted. The Company is currently evaluating the impact of this new standard on its consolidated financial statements and the adoption is not expected to have a significant impact on the consolidated financial statements. Income Tax - In December 2019, the FASB issued ASU 2019-12, which modifies ASC 740 to simplify the accounting for income taxes. The ASU’s amendments are based on changes that were suggested by stakeholders as part of the FASB’s simplification initiative (i.e., the FASB’s effort to reduce the complexity of accounting standards while maintaining or enhancing the helpfulness of information provided to financial statement users). ASU 2019-12 is effective for fiscal years beginning after December 15, 2022. The Company is currently evaluating the impact of this new standard on its consolidated financial statements and the adoption is not expected to have a significant impact on the consolidated financial statements.

Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2021

Fair Value Disclosures [Abstract]

Liabilities measured at fair value by level

The following table summarizes the Company’s liabilities measured at fair value as of the dates presented, by level within the fair value hierarchy (in thousands):


	Level 1		Level 2		Level 3
March 31, 2021
Promissory note	$	—	$	—	$	16,128
December 31, 2020
Promissory note	$	—	$	—	$	15,392
December 31, 2019
Promissory note	$	—	$	—	$	16,169

Changes in fair value of promissory notes

The following table includes the changes in fair value of the promissory note which are Level 3 on the fair value hierarchy (in thousands):


January 1, 2019	$	15,852
Interest expense accrued	150
Increase in fair value	167
December 31, 2019	16,169
Interest expense accrued	150
Decrease in fair value	(927)
December 31, 2020	15,392
Interest expense accrued	37
Increase in fair value	699
March 31, 2021	$	16,128

Fair value of prommissory note

The following table summarizes assumptions used for fair value of promissory note for the periods presented:


	As of March 31, 2021	As of December 31,
		2020	2019
Stock price	$3.75	$3.00	$3.01
Time	1.5 years	1.75 years	0.25 years
Risk-free rate	0.12%	0.12%	1.55%
Volatility	50.6%	62.3%	38.2%

Concentration of Credit Risk and Significant Customers (Tables)

3 Months Ended

Mar. 31, 2021

Risks and Uncertainties [Abstract]

Schedules of concentration of risk, by risk factor

Significant customers are those that represent 10% or more of revenue or accounts receivable and are set forth in the following tables:


		As of March 31, 2021	As of December 31,
Accounts Receivable			2020	2019
Customer A		31.1%	49.3%	60.0%
Customer B		33.9%	31.9%	20.4%
Customer C		10.0%	*	*

	For the Three Months Ended March 31,		For the Year Ended December 31,
Revenue	2021	2020 (unaudited)	2020	2019
Customer A	27.3%	31.3%	59.6%	79.6%
Customer B	31.2%	53.2%	29.2%	13.3%

* Less than 10% of total

Inventory (Tables)

3 Months Ended

Mar. 31, 2021

Inventory Disclosure [Abstract]

Schedule of inventory

Inventory consists of the following as of the dates presented (in thousands):


			December 31,
	March 31, 2021		2020		2019
Raw materials	$	626	$	633	$	412
Work in process	1,054		350		258
Finished goods	543		644		320
Total	$	2,223	$	1,627	$	990

Property, Plant, and Equipment (Tables)

3 Months Ended

Mar. 31, 2021

Property, Plant and Equipment [Abstract]

Schedule of property and equipment

Property and equipment as of the dates presented consists of the following (in thousands except years):


			December 31,				Estimated Useful Life (in years)
	March 31, 2021		2020		2019
Machinery and equipment	$	14,748	$	14,924	$	14,892	5
Computer equipment and software	836		828		876		3
Furniture and fixtures	185		189		186		7
Leasehold improvements (1)	4,959		4,970		4,954		7
Construction in progress	137		13		6
Property and equipment, gross	20,865		20,924		20,914
Less: accumulated depreciation and amortization	(19,505)		(19,600)		(19,144)
Property and equipment, net	$	1,360	$	1,324	$	1,770

(1) Leasehold improvements are amortized on a straight-line basis over the shorter of their estimated useful lives or the related remaining lease term.

Intangible Assets (Tables)

3 Months Ended

Mar. 31, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of carrying value of intangible assets

The carrying values of intangible assets as of the dates presented, respectively, consists of the following (in thousands except years):


	March 31, 2021
	Gross		Accumulated Amortization		Foreign Exchange Rate Changes		Net		Estimated Useful Life (in years)
Patents	$	2,963	$	(2,049)	$	—	$	914	10
Developed technology - 150V	560		(517)		(43)		—		6
Developed technology - 600V	1,701		(1,570)		(131)		—		6
Total	$	5,224	$	(4,136)	$	(174)	$	914

	December 31, 2020
	Gross		Accumulated Amortization		Foreign Exchange Rate Changes		Net		Estimated Useful Life (in years)
Patents	$	2,963	$	(1,975)	$	—	$	988	10
Developed technology - 150V	560		(555)		(5)		—		6
Developed technology - 600V	1,701		(1,684)		(17)		—		6
Total	$	5,224	$	(4,214)	$	(22)	$	988

	December 31, 2019
	Gross		Accumulated Amortization		Foreign Exchange Rate Changes		Net		Estimated Useful Life (in years)
Patents	$	2,963	$	(1,679)	$	—	$	1,284	10
Developed technology - 150V	560		(519)		(34)		7		6
Developed technology - 600V	1,701		(1,575)		(104)		22		6
Total	$	5,224	$	(3,773)	$	(138)	$	1,313

Schedule of estimated future amortization expenses related to intangible assets

Estimated future amortization expenses related to intangible assets as of March 31, 2021 were as follows (in thousands):


2022	$	296
2023	296
2024	296
2025	26
Thereafter	—
Total	$	914

Debts (Tables)

3 Months Ended

Mar. 31, 2021

Debt Disclosure [Abstract]

Schedule of promissory note obligation

The Company’s stated value of promissory note obligation as of the dates presented consists of the following (in thousands):


					December 31,
	Interest Rate	Due Date	March 31, 2021		2020		2019
Yaskawa Note	1.00%	September 2022	$	15,523	$	15,486	$	15,336

Schedule of fair value option

As of the dates presented, the Company determined the fair value for the note, as compared to the face value, including accrued interest, as follows (in thousands):


			December 31,
	March 31, 2021		2020		2019
Yaskawa Note	$	16,128	$	15,392	$	16,169

Schedule of maturities of long-term debt

As of March 31, 2021, the scheduled maturity on the development loans, revolving credit facility and promissory note was as follows (in thousands):


2022	$	20,150
2023	15,748
Thereafter	—
Total	$	35,898

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

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+ Details

Investment in Aizu Fujitsu Semiconductor Wafer Solution Limited ("AFSW") (Tables)

3 Months Ended

Mar. 31, 2021

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of investment activities in AFSW

The Company’s investment activities in AFSW for the periods presented are summarized below (in thousands):


January 1, 2019	$	(659)
Investment	2,698
Loss	(3,703)
Effect of exchange rate change	(24)
December 31, 2019	(1,688)
Investment	7,348
Loss	(6,836)
Effect of exchange rate change	(290)
December 31, 2020	(1,466)
Investment	968
Loss	(1,468)
Effect of exchange rate change	100
March 31, 2021	$	(1,866)

Summarized financial information of AFSW for the periods indicated, as provided by the controlling owner, are as follows (in thousands):


			As of March 31, 2021		As of December 31,
					2020		2019
Current assets			$	932	$	1,503	$	3,733
Long-term assets			$	5,330	$	5,572	$	5,101
Other current liabilities			$	2,200	$	2,521	$	931
Due to controlling owner			$	22,354	$	22,136	$	17,913
Due to Transphorm			$	13,179	$	12,967	$	5,349
Net deficit			$	(31,471)	$	(30,549)	$	(15,359)

	For the Three Months Ended March 31,				For the Year Ended December 31,
	2021		2020 (unaudited)		2020		2019
Sales	$	842	$	1,248	$	2,976	$	11,599
Gross loss	$	(2,425)	$	(2,197)	$	(11,411)	$	(4,849)
Net loss	$	(2,995)	$	(2,895)	$	(13,952)	$	(7,557)

- Definition

Tabular disclosure of the significant judgments and assumptions made in determining whether a variable interest (as defined) held by the entity requires the variable interest entity (VIE) (as defined) to be consolidated and (or) disclose information about its involvement with the VIE, individually or in aggregate (as applicable); the nature of restrictions, if any, on the consolidated VIE's assets and on the settlement of its liabilities reported by an entity in its statement of financial position, including the carrying amounts of such assets and liabilities; the nature of, and changes in, the risks associated with involvement in the VIE; how involvement with the VIE affects the entity's financial position, financial performance, and cash flows; the lack of recourse if creditors (or beneficial interest holders) of the consolidated VIE have no recourse to the general credit of the primary beneficiary (if applicable); the terms of arrangements, giving consideration to both explicit arrangements and implicit variable interests, if any, that could require the entity to provide financial support to the VIE, including events or circumstances that could expose the entity to a loss; the methodology used by the entity for determining whether or not it is the primary beneficiary of the variable interest entity; the significant factors considered and judgments made in determining that the power to direct the activities of a VIE that most significantly impact the VIE's economic performance are shared (as defined); the carrying amounts and classification of assets and liabilities of the VIE included in the statement of financial position; the entity's maximum exposure to loss, if any, as a result of its involvement with the VIE, including how the maximum exposure is determined and significant sources of the entity's exposure to the VIE; a comparison of the carrying amounts of the assets and liabilities and the entity's maximum exposure to loss; information about any liquidity arrangements, guarantees, and (or) other commitments by third parties that may affect the fair value or risk of the entity's variable interest in the VIE; whether or not the entity has provided financial support or other support (explicitly or implicitly) to the VIE that it was not previously contractually required to provide or whether the entity intends to provide that support, including the type and amount of the support and the primary reasons for providing the support; and supplemental information the entity determines necessary to provide.

+ References + Details

Commitment and Contingencies (Tables)

3 Months Ended

Mar. 31, 2021

Commitments and Contingencies Disclosure [Abstract]

Schedule of future minimum operating lease commitments

As of March 31, 2021, future minimum operating lease commitments were as follows (in thousands):


2022	$	681
2023	322
2024	241
2025	60
Thereafter	—
Total	$	1,304

Convertible Preferred Stock (Tables)

3 Months Ended

Mar. 31, 2021

Equity [Abstract]

Schedule of convertible preferred stock by class

As of December 31, 2019, the Company’s convertible preferred stock consisted of the following (in thousands, except share and per share data on a post conversion basis):


	Authorized Shares	Outstanding Shares	Carrying Value		Par Value per Share		Preference Value
Series 1	12,438,704	12,433,953	$	39,658	$	0.001	$	40,000
Series 2	7,507,699	7,499,996	$	30,000	$	0.001	$	30,000
Series 3	4,000,000	4,000,000	$	16,000	$	0.001	$	16,000
Total	23,946,403	23,933,949	$	85,658			$	86,000

The Company has reserved shares of common stock for future issuance as of dates presented as follows:


			March 31, 2021
Equity incentive plans			5,039,025
Common stock warrants			159,415
Total			5,198,440

- Definition

Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.

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+ Details

Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 2021

Equity [Abstract]

Schedule of convertible preferred stock by class

As of December 31, 2019, the Company’s convertible preferred stock consisted of the following (in thousands, except share and per share data on a post conversion basis):


	Authorized Shares	Outstanding Shares	Carrying Value		Par Value per Share		Preference Value
Series 1	12,438,704	12,433,953	$	39,658	$	0.001	$	40,000
Series 2	7,507,699	7,499,996	$	30,000	$	0.001	$	30,000
Series 3	4,000,000	4,000,000	$	16,000	$	0.001	$	16,000
Total	23,946,403	23,933,949	$	85,658			$	86,000

The Company has reserved shares of common stock for future issuance as of dates presented as follows:


			March 31, 2021
Equity incentive plans			5,039,025
Common stock warrants			159,415
Total			5,198,440

Schedule of stockholders' equity note, warrants or rights

The following warrants to purchase common stock were outstanding as of March 31, 2021:


Number of Shares	Exercise Price		Expiration Date
6,046	$	34.74	5 years after an initial public offering of the Company
3,369	$	54.41	5 years after an initial public offering of the Company
150,000	$	3.30	December 23, 2025
159,415

- Definition

+ References

+ Details

Stock Based Compensation (Tables)

3 Months Ended

Mar. 31, 2021

Share-based Payment Arrangement [Abstract]

Schedule of stock option activity

The following table summarizes stock option activity and related information for the dates presented:


	Number of Options	Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Term (in Years)	Aggregate Intrinsic Value (1) (in thousands)
Outstanding at January 1, 2021	2,320,318	$	4.67	5.92	$	—
Options granted	223,638	$	6.37
Options exercised	(500)	$	3.14
Options canceled	(331)	$	9.29
Outstanding at March 31, 2021	2,543,125	$	4.82	6.05	$	—
Exercisable at March 31, 2021	2,283,243	$	4.70	5.65	$	—

Outstanding at January 1, 2020	2,473,198	$	4.67	6.84	$	—
Options granted	—	$	—
Options exercised	(6,821)	$	3.78
Options canceled	(146,059)	$	5.88
Outstanding at December 31, 2020	2,320,318	$	4.67	5.92	$	—
Exercisable at December 31, 2020	2,267,154	$	4.70	5.86	$	—

Outstanding at January 1, 2019	2,377,180	$	4.79	7.46	$	—
Options granted	209,908	$	3.14
Options exercised	(1,392)	$	3.86
Options canceled	(112,498)	$	4.34
Outstanding at December 31, 2019	2,473,198	$	4.67	6.84	$	—
Exercisable at December 31, 2019	2,079,809	$	4.95	6.65	$	—

Schedule of valuation assumptions

The assumptions used to value options granted to employees during the periods presented was as follows:


	Three Months Ended March 31, 2021	Year Ended December 31,
		2020	2019
Weighted average expected life (in years)	5.23	—	5.46
Risk-free interest rate	0.78% - 1.73%	—	1.34% - 1.94%
Expected volatility	43.1% - 44.3%	—	39.4% - 39.8%
Grant date fair market value	3.75		3.01
Grant date fair value	$0.94 - $1.65	—	$0.98 - $1.10
Dividend yield	—%	—	—%

Schedule of unvested restricted stock units

The following table summarizes RSA activity and related information for the periods presented:


	Number of Shares	Weighted-Average Grant Date Fair Value Per Share
January 1, 2020	—	$	—
Granted	135,501	$	3.91
Vested	(98,450)	$	3.88
December 31, 2020	37,051	$	4.00
Granted	—	$	—
Vested	(37,051)	$	4.00
March 31, 2021	—	$	—

The following table summarizes RSU activity and related information for the periods presented:


	Number of Shares	Weighted-Average Grant Date Fair Value Per Share
January 1, 2020	—	$	—
Granted	816,180	$	4.00
Vested	(4,000)	$	4.00
Canceled	(6,855)	$	4.00
December 31, 2020	805,325	$	4.00
Granted	137,452	$	3.75
Vested	(3,000)	$	3.75
Canceled	(4,380)	$	4.00
March 31, 2021	935,397	$	3.96

Stock-based compensation expense

The accompanying consolidated statement of operations and comprehensive loss includes stock-based compensation expense for the periods presented as follows (in thousands):


	Three Months Ended March 31,				Year Ended December 31,
	2021		2020 (unaudited)		2020		2019
Cost of revenue	$	39	$	15	$	93	$	60
Research and development	115		46		306		196
Sales and marketing	33		7		68		30
General and administrative	326		64		1,058		280
Total	$	513	$	132	$	1,525	$	566

Unrecognized stock-based compensation

Unrecognized stock-based compensation expense as of dates presented was as follows (in thousands):


	March 31, 2021			December 31, 2020			December 31, 2019
	Unrecognized Expense		Average Expected Recognition Period	Unrecognized Expense		Average Expected Recognition Period	Unrecognized Expense		Average Expected Recognition Period
Stock options	$	280	5.06 years	$	54	0.67 years	$	464	1.20 years
Restricted stock	2,738		1.76 years	2,687		1.87 years	—		—
Total	$	3,018	2.07 years	$	2,741	1.85 years	$	464	1.20 years

Income Taxes (Tables)

3 Months Ended

Mar. 31, 2021

Income Tax Disclosure [Abstract]

Schedule of significant components of deferred tax assets and liabilities

Significant components of the Company’s deferred tax assets and deferred tax liabilities as of the dates presented as follows (in thousands):


			December 31,
	March 31, 2021		2020		2019
Deferred tax assets:
Net operating loss carryforwards	$	47,424	$	46,346	$	43,973
Tax credits	5,444		5,262		4,535
California capitalized research and development	72		80		343
Fixed assets	—		8		—
Others, net	581		593		602
Total deferred tax assets	53,521		52,289		49,453
Valuation allowance	(53,481)		(52,289)		(49,403)
Deferred tax asset, net of valuation allowance	40		—		50
Deferred tax liabilities:
Others, net	—		—		—
Fixed assets	(40)		—		(50)
Total deferred tax liabilities	(40)		—		(50)
Net deferred tax assets	$	—	$	—	$	—

Schedule of reconciliation between the federal statutory rate and the effective tax rate

Reconciliation between federal statutory tax rate and the effective tax rate is shown in the following table for the periods presented:


	Three Months Ended March 31, 2021		Year Ended December 31,
			2020		2019
Federal statutory income tax rate	21.00	%	21.00	%	21.00	%
Research and development credit	2.73	%	4.06	%	4.76	%
Nondeductible expense	(2.43)	%	0.64	%	(3.18)	%
Loss in joint venture	(6.76)	%	(11.70)	%	(7.44)	%
Foreign income tax rate difference	2.45	%	4.10	%	2.99	%
Others, net	0.85	%	(2.08)	%	(0.75)	%
Valuation allowance	(17.84)	%	(16.02)	%	(17.38)	%
Effective tax rate	—	%	—	%	—	%

Business and Basis of Presentation (Details) - USD ($)		1 Months Ended			3 Months Ended		12 Months Ended
Business and Basis of Presentation (Details) - USD ($)	Feb. 12, 2020	Mar. 31, 2021	Dec. 31, 2020	Feb. 29, 2020	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Feb. 11, 2020	Jan. 01, 2020	Dec. 31, 2018
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Merger conversion rate (in shares)	0.08289152527
Common stock, shares issued (in shares)	4,171,571	40,531,996	40,531,996		40,531,996		40,531,996	4,220,998	50,325,662
Common stock, forfeited and cancelled (in shares)	682,699
Shares issued under company plans (in shares)	2,461,923	2,543,125	2,320,318		2,543,125		2,320,318	2,473,198		2,473,198	2,377,180
Number of shares (in shares)	15,461	159,415			159,415				186,535
Conversion price per share on convertible note payable (in dollars per share)	$ 5.12
Maximum number of shares of common stock issuable (in shares)	3,076,171
Proceeds from issuance of common stock, net of offering cost		$ 1,000,000.0	$ 13,600,000	$ 19,700,000	$ 950,000	$ 19,741,000	$ 33,387,000	$ 0
Yaskawa Note
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Maximum number of shares of common stock issuable (in shares)	3,076,171
Principal amount of long term loan facility			15,000,000.0				15,000,000.0
Accrued interest on promissory note		$ 523,000	$ 486,000		$ 523,000		$ 486,000	$ 336,000
Transphorm Technology 2007 Stock Plan and 2015 Equity Incentive Plan
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Shares issued under company plans (in shares)	29,703,285
Series 1 Preferred Stock
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Convertible preferred stock, shares issued (in shares)	51,680,254
Convertible preferred stock, shares outstanding (in shares)	51,680,254
Share conversion in connection with the Merger (in shares)	12,433,953
Series 2 Preferred Stock
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Convertible preferred stock, shares issued (in shares)	38,760,190
Convertible preferred stock, shares outstanding (in shares)	38,760,190
Conversion of stock (in shares)	7,499,996
Series 3 Preferred Stock
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Convertible preferred stock, shares issued (in shares)	31,850,304
Convertible preferred stock, shares outstanding (in shares)	31,850,304
Conversion of stock (in shares)	4,000,000
Common Stock
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Price per share (in dollars per share)	$ 4.00
Share conversion in connection with the Merger (in shares)						23,933,949	23,933,949
Transphorm Technology
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Share conversion in connection with the Merger (in shares)	28,105,520

Summary of Significant Accounting Policies (Details)		1 Months Ended	3 Months Ended			9 Months Ended	12 Months Ended
Summary of Significant Accounting Policies (Details)	Feb. 12, 2020 USD ($)	Dec. 31, 2020 USD ($)	Mar. 31, 2021 USD ($) segment shares	Sep. 30, 2020 USD ($)	Mar. 31, 2020 USD ($) shares	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($) shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($)
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents		$ 14,694,000	$ 9,500,000			$ 9,500,000	$ 14,694,000	$ 2,875,000
Provision for doubtful accounts		$ 110,000	48,000		$ 0	48,000	110,000	0
Goodwill impairment charges			0				0	0
Impairment of intangible assets			0				0	0
Revenue from product and license fees			2,425,000		1,100,000		11,371,000	11,934,000
Term of cooperation and development agreement.		3 years
Revenue recognized for collaboration development activities			333,000				333,000
Deferred revenue		$ 674,000	505,000			505,000	674,000	0
Cumulative effect of government rate change			(83,000)	$ 505,000		423,000
Grant reimbursement			$ 42,000		$ 72,000		$ 426,000	$ 0
Number of anti-dilutive shares (in shares) \| shares			3,637,937		2,473,552		3,285,058	26,422,608
Number of reportable segments \| segment			1
Yaskawa
Cash and Cash Equivalents [Line Items]
Letter of intent for development activities	$ 4,000,000.0	4,000,000.0
Proceeds from collaborators		1,000,000.0
Revenue recognized for collaboration development activities			$ 333,000				$ 333,000
Deferred revenue		667,000	334,000			334,000	667,000
Other Assets
Cash and Cash Equivalents [Line Items]
Restricted cash		75,000	$ 75,000			75,000	75,000	$ 75,000
License and Service
Cash and Cash Equivalents [Line Items]
Revenue from product and license fees							$ 5,000,000.0	6,000,000.0	$ 3,000,000.0
Recognition of contractual income								$ 9,000,000.0
Stock options
Cash and Cash Equivalents [Line Items]
Number of anti-dilutive shares (in shares) \| shares			2,543,125		2,458,091		2,320,318	2,473,198
Convertible Preferred Stock
Cash and Cash Equivalents [Line Items]
Number of anti-dilutive shares (in shares) \| shares								23,933,949
Warrant
Cash and Cash Equivalents [Line Items]
Number of anti-dilutive shares (in shares) \| shares			159,415		15,461		159,415	15,461
Restricted Stock Awards (RSA)
Cash and Cash Equivalents [Line Items]
Number of anti-dilutive shares (in shares) \| shares			935,397				805,325
Minimum
Cash and Cash Equivalents [Line Items]
Property and equipment, estimated useful life			3 years
Intangible assets, estimated useful life			3 years
Award vesting period			1 year
Maximum
Cash and Cash Equivalents [Line Items]
Property and equipment, estimated useful life			7 years
Intangible assets, estimated useful life			10 years
Award vesting period			4 years
JAPAN
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents		$ 42,000	$ 444,000			$ 444,000	$ 42,000	$ 55,000
Percentage of cash and cash equivalents in foreign subsidiary		0.30%	4.70%			4.70%	0.30%	1.90%
Revenue from product and license fees			$ 449,000		$ 11,000		$ 713,000	$ 28,000
UNITED STATES
Cash and Cash Equivalents [Line Items]
Revenue from product and license fees			$ 2,000,000.0		$ 1,100,000		$ 10,700,000	$ 11,900,000

Nexperia Arrangement (Details) - USD ($)			1 Months Ended						2 Months Ended	12 Months Ended
Nexperia Arrangement (Details) - USD ($)	Apr. 04, 2018	Mar. 26, 2018	Jun. 30, 2020	Dec. 31, 2019	Oct. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2019
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
License fees	$ 9,000,000		$ 5,000,000		$ 3,000,000	$ 3,000,000		$ 3,000,000		$ 9,000,000.0
Series 3 Preferred Stock
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Issuance of preferred stock	16,000,000	$ 16,000,000
Tranche A Loan
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Long-term loan facility	5,000,000
Reduction of debt			$ 5,000,000
Proceeds from Issuance of debt							$ 5,000,000
Tranche B Loan
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Long-term loan facility	10,000,000								$ 8,000,000.0			$ 8,000,000
Proceeds from Issuance of debt									$ 8,000,000
Tranche B-1 Loan
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Long-term loan facility				$ 2,000,000						$ 2,000,000		$ 2,000,000
Proceeds from Issuance of debt				$ 2,000,000
Tranche C Loan
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revolving loan	$ 10,000,000
Proceeds from Issuance of debt											$ 10,000,000

Fair Value Measurements - Fair Value Hierarchy (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Promissory note	$ 0	$ 0	$ 0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Promissory note	0	0	0
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Promissory note	$ 16,128	$ 15,392	$ 16,169

Fair Value Measurements - Changes in Level 3 inputs (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
January 1, 2019	$ 15,392	$ 16,169	$ 15,852
Interest expense accrued	37	150	150
Increase (decrease) in fair value	699	(927)	167
Fair value at period end	$ 16,128	$ 15,392	$ 16,169

Fair Value Measures - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Interest expense	$ 37	$ 37	$ 150	$ 150
Increase (decrease) in fair value	$ 699		$ (927)	$ 167

Fair Value Measurements - Fair value measurement inputs (Details)	Mar. 31, 2021 $ / shares	Dec. 31, 2020 $ / shares	Dec. 31, 2019 $ / shares
Stock price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Promissory note, fair value measurement inputs	3.75	3.00	3.01
Time
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Promissory note, expected term	1 year 6 months	1 year 9 months	3 months
Risk-free rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Promissory note, fair value measurement inputs	0.0012	0.0012	0.0155
Volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Promissory note, fair value measurement inputs	0.506	0.623	0.382

Concentration of Credit Risk and Significant Customers (Details) - Customer Concentration Risk	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Revenue \| Customer A
Concentration Risk [Line Items]
Percentage of revenue or accounts receivable	27.30%	31.30%	59.60%	79.60%
Revenue \| Customer B
Concentration Risk [Line Items]
Percentage of revenue or accounts receivable	31.20%	53.20%	29.20%	13.30%
Accounts Receivable \| Customer A
Concentration Risk [Line Items]
Percentage of revenue or accounts receivable	31.10%		49.30%	60.00%
Accounts Receivable \| Customer B
Concentration Risk [Line Items]
Percentage of revenue or accounts receivable	33.90%		31.90%	20.40%
Accounts Receivable \| Customer C
Concentration Risk [Line Items]
Percentage of revenue or accounts receivable	10.00%

Inventory (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
Inventory (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 626		$ 633	$ 412
Work in process	1,054		350	258
Finished goods	543		644	320
Total	2,223		1,627	990
Inventory write-off	$ 7	$ 169	$ 435	$ 155

Property and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
Property and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 20,865		$ 20,924	$ 20,914
Less: accumulated depreciation and amortization	(19,505)		(19,600)	(19,144)
Property and equipment, net	1,360		1,324	1,770
Depreciation and amortization related to property, plant, and equipment	123	$ 133	509	563
Gain on sale of equipment	40	$ 0	0	0
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 14,748		14,924	14,892
Estimated Useful Life (in years)	5 years
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 836		828	876
Estimated Useful Life (in years)	3 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 185		189	186
Estimated Useful Life (in years)	7 years
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 4,959		4,970	4,954
Estimated Useful Life (in years)	7 years
Construction in Progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 137		$ 13	$ 6

Intangible Assets - Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 5,224		$ 5,224	$ 5,224
Finite-Lived Intangible Assets, Accumulated Amortization	(4,136)		(4,214)	(3,773)
Finite Lived Intangible Assets, Accumulated Change in Foreign Exchange Rate	(174)		(22)	(138)
Total	914		988	1,313
Amortization expense	74	$ 103	326	653
Patents
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	2,963		2,963	2,963
Finite-Lived Intangible Assets, Accumulated Amortization	(2,049)		(1,975)	(1,679)
Finite Lived Intangible Assets, Accumulated Change in Foreign Exchange Rate	0		0	0
Total	$ 914		$ 988	$ 1,284
Intangible assets, estimated useful life	10 years		10 years	10 years
Developed Technology - 150V
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 560		$ 560	$ 560
Finite-Lived Intangible Assets, Accumulated Amortization	(517)		(555)	(519)
Finite Lived Intangible Assets, Accumulated Change in Foreign Exchange Rate	(43)		(5)	(34)
Total	$ 0		$ 0	$ 7
Intangible assets, estimated useful life	6 years		6 years	6 years
Developed Technology - 600V
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 1,701		$ 1,701	$ 1,701
Finite-Lived Intangible Assets, Accumulated Amortization	(1,570)		(1,684)	(1,575)
Finite Lived Intangible Assets, Accumulated Change in Foreign Exchange Rate	(131)		(17)	(104)
Total	$ 0		$ 0	$ 22
Intangible assets, estimated useful life	6 years		6 years	6 years

Intangible Assets - Estimated Future Amortization Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
2022	$ 296
2023	296
2024	296
2025	26
Thereafter	0
Total	$ 914	$ 988	$ 1,313

Debts - Additional Information (Details)		1 Months Ended	3 Months Ended		12 Months Ended
Debts - Additional Information (Details)	Feb. 12, 2020 USD ($) shares $ / shares	Dec. 31, 2020 USD ($)	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jul. 31, 2019 USD ($)	Mar. 31, 2019 USD ($)	Apr. 04, 2018 USD ($)	Oct. 31, 2017 USD ($)
Line of Credit Facility [Line Items]
Aggregate principal amount of loans outstanding			$ 35,898,000
Accrued interest on promissory note			37,000	$ 37,000	$ 150,000	$ 150,000
Outstanding balance on line of credit facility		$ 10,200,000	10,200,000		10,200,000	10,500,000
Changes in fair value of promissory note			699,000	(2,321,000)	(927,000)	167,000
Maximum number of shares of common stock issuable (in shares) \| shares	3,076,171
Conversion price per share on convertible note payable (in dollars per share) \| $ / shares	$ 5.12
Interest expense			187,000	189,000	760,000	758,000
Term of cooperation and development agreement.		3 years
Deferred revenue		$ 674,000	505,000		674,000	0
Accounts Payable and Accrued Liabilities
Line of Credit Facility [Line Items]
Interest expense			153,000	0	915,000	496,000
Yaskawa
Line of Credit Facility [Line Items]
Letter of intent for development activities	$ 4,000,000.0	4,000,000.0
Proceeds from collaborators		1,000,000.0
Deferred revenue		667,000	334,000		667,000
Loan and Security Agreement (LSA)
Line of Credit Facility [Line Items]
Long-term loan facility									$ 15,000,000.0
Aggregate principal amount of loans outstanding		10,000,000.0	10,000,000.0		10,000,000.0	15,000,000.0
Tranche A Loan
Line of Credit Facility [Line Items]
Long-term loan facility									5,000,000
Tranche B Loan
Line of Credit Facility [Line Items]
Long-term loan facility							$ 8,000,000.0	$ 8,000,000	10,000,000
Tranche B-1 Loan
Line of Credit Facility [Line Items]
Long-term loan facility						2,000,000		$ 2,000,000
Tranche C Note
Line of Credit Facility [Line Items]
Long-term loan facility									10,000,000.0
Revolving loan									$ 10,000,000.0
Interest rate per annum									6.00%
Accrued interest on promissory note			$ 150,000	152,000	610,000	608,000
Yaskawa Note
Line of Credit Facility [Line Items]
Interest rate per annum			1.00%							1.00%
Changes in fair value of promissory note			$ (699,000)		927,000	(167,000)
Unsecured subordinated convertible promissory note		15,486,000	15,523,000		15,486,000	15,336,000				$ 15,000,000.0
Maximum number of shares of common stock issuable (in shares) \| shares	3,076,171
Interest expense			37,000	$ 37,000	150,000	150,000
Accrued interest on promissory note		$ 486,000	$ 523,000		$ 486,000	$ 336,000

Debts - Notes Payable (Details) - Yaskawa Note - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Oct. 31, 2017
Line of Credit Facility [Line Items]
Interest rate per annum	1.00%			1.00%
Unsecured subordinated convertible promissory note	$ 15,523	$ 15,486	$ 15,336	$ 15,000
Promissory note	$ 16,128	$ 15,392	$ 16,169

Debts - Maturities Schedule (Details) $ in Thousands	Mar. 31, 2021 USD ($)
Debt Disclosure [Abstract]
2022	$ 20,150
2023	15,748
Thereafter	0
Total	$ 35,898

Investment in Aizu Fujitsu Semiconductor Wafer Solution Limited ("AFSW") - Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended		12 Months Ended		15 Months Ended
	Dec. 31, 2020	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Jun. 30, 2021	Dec. 31, 2018
Variable Interest Entity [Line Items]
Term of agreement to maintain and continue AFSW	1 year
Third Party
Variable Interest Entity [Line Items]
Ownership percentage	75.00%			75.00%
Aizu Fajitsu Semiconductor Wafer Solution Limited
Variable Interest Entity [Line Items]
Ownership percentage in entity		49.00%
Additional financial support provided to investment		$ 968,000	$ 1,500,000	$ 7,348,000	$ 2,698,000
Unfunded commitment	$ 1,466,000	$ 1,866,000		$ 1,466,000	$ 1,688,000		$ 659,000
Forecast
Variable Interest Entity [Line Items]
Expected exercise price under certain conditions						$ 1
Minimum number of days before closing						60 days
Fujitsu Semiconductor Limited \| Aizu Fajitsu Semiconductor Wafer Solution Limited
Variable Interest Entity [Line Items]
Ownership percentage in entity		51.00%
Fujitsu Semiconductor Limited \| Forecast
Variable Interest Entity [Line Items]
Purchase of additional interest						51.00%

Investment in Aizu Fujitsu Semiconductor Wafer Solution Limited ("AFSW") - Income Statement Information (Details) - Aizu Fajitsu Semiconductor Wafer Solution Limited - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Summary of Variable Interest Entities [Roll Forward]
Beginning balance	$ (1,466)	$ (1,688)	$ (1,688)	$ (659)
Investment	968	$ 1,500	7,348	2,698
Loss	(1,468)		(6,836)	(3,703)
Effect of exchange rate change	100		(290)	(24)
Ending balance	$ (1,866)		$ (1,466)	$ (1,688)

Investment in Aizu Fujitsu Semiconductor Wafer Solution Limited ("AFSW") - Summarized Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Current assets	$ 14,294		$ 18,226	$ 5,357
Other current liabilities	1,866		1,466	1,688
Aizu Fajitsu Semiconductor Wafer Solution Limited
Variable Interest Entity [Line Items]
Current assets	932		1,503	3,733
Long-term assets	5,330		5,572	5,101
Other current liabilities	2,200		2,521	931
Net deficit	(31,471)		(30,549)	(15,359)
Variable Interest Entity, Measure of Activity [Abstract]
Sales	842	$ 1,248	2,976	11,599
Gross loss	(2,425)	(2,197)	(11,411)	(4,849)
Net loss	(2,995)	$ (2,895)	(13,952)	(7,557)
Fujitsu Semiconductor Limited \| Aizu Fajitsu Semiconductor Wafer Solution Limited
Variable Interest Entity [Line Items]
Accounts payable due to related parties	22,354		22,136	17,913
Transphorm, Inc. \| Aizu Fajitsu Semiconductor Wafer Solution Limited
Variable Interest Entity [Line Items]
Accounts payable due to related parties	$ 13,179		$ 12,967	$ 5,349

Commitment and Contingencies - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitment to acquire equipment and services	$ 7,400
Cumulative purchases made to date	6,900
Reimbursement received from government agency	6,900
Amount purchased	270		$ 6,200
Remaining accounts payable to vendors	124		1,000
Rent expense	212	$ 233	892	$ 897
Rental income from noncancelable sublease	30	$ 45	$ 182	$ 182
Future minimum rental payments to be received under sublease	$ 0

Commitment and Contingencies - Operating Lease Maturity Schedule (Details) $ in Thousands	Mar. 31, 2021 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2022	$ 681
2023	322
2024	241
2025	60
Thereafter	0
Total	$ 1,304

Convertible Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)			23,946,403
Preferred stock, shares outstanding (in shares)	0	0	23,933,949
Carrying Value			$ 85,658
Par Value Per Share (in usd per share)			$ 0.0001
Preference Value			$ 86,000
Series 1 Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)			12,438,704
Preferred stock, shares outstanding (in shares)			12,433,953
Carrying Value			$ 39,658
Par Value Per Share (in usd per share)			$ 0.001
Preference Value			$ 40,000
Series 2 Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)			7,507,699
Preferred stock, shares outstanding (in shares)			7,499,996
Carrying Value			$ 30,000
Par Value Per Share (in usd per share)			$ 0.001
Preference Value			$ 30,000
Series 3 Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)			4,000,000
Preferred stock, shares outstanding (in shares)			4,000,000
Carrying Value			$ 16,000
Par Value Per Share (in usd per share)			$ 0.001
Preference Value			$ 16,000

Convertible Preferred Stock - Narrative (Details)			12 Months Ended
Convertible Preferred Stock - Narrative (Details)	Apr. 04, 2018 USD ($)	Mar. 26, 2018 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) segment $ / shares Rate shares	Mar. 31, 2021 $ / shares shares	Dec. 31, 2020 $ / shares shares	Feb. 11, 2020 shares
Class of Stock [Line Items]
Preferred stock automatically converts into aggregate net proceeds (at least) \| $			$ 40,000,000
Underwritten public offering of common stock, minimum aggregate net proceeds \| $			$ 40,000,000
Minimum ratio offering price per share of OIP \| Rate			150.00%
Series 1 Preferred Stock
Class of Stock [Line Items]
Convertible preferred stock, shares issued (in shares) \| shares			12,433,953	0	0	51,680,254
Convertible preferred stock, par value (in usd per share)			$ 0.0001	$ 0.0001	$ 0.0001
Convertible preferred stock, liquidation rights per share (in usd per share)			3.217
Convertible preferred stock, dividend rate (in usd per share)			$ 0.25736
Number of common stock shares converted per preferred share (in shares) \| shares			10
Series 1 Preferred Stock \| KKR Phorm Investors L.P. (KKR)
Class of Stock [Line Items]
Convertible preferred stock, shares issued (in shares) \| shares			12,433,953
Convertible preferred stock, par value (in usd per share)			$ 0.001
Convertible preferred stock, price per share (in usd per share)			$ 3.217
Issuance of preferred stock \| $			$ 40,000,000
Series 2 Preferred Stock
Class of Stock [Line Items]
Convertible preferred stock, shares issued (in shares) \| shares			7,499,996	0	0	38,760,190
Convertible preferred stock, par value (in usd per share)			$ 0.0001	$ 0.0001	$ 0.0001
Convertible preferred stock, liquidation rights per share (in usd per share)			4.00
Convertible preferred stock, dividend rate (in usd per share)			0.32
Series 2 Preferred Stock \| KKR Phorm Investors L.P. (KKR)
Class of Stock [Line Items]
Convertible preferred stock, par value (in usd per share)			0.001
Convertible preferred stock, price per share (in usd per share)			$ 4.00
Issuance of preferred stock \| $			$ 30,000,000
Series 2 Preferred Stock \| Other Investors \| KKR Phorm Investors L.P. (KKR)
Class of Stock [Line Items]
Convertible preferred stock, shares issued (in shares) \| shares			7,499,996
Other investors with a small percentage			0.02%
Series 3 Preferred Stock
Class of Stock [Line Items]
Convertible preferred stock, shares issued (in shares) \| shares		4,000,000	4,000,000	0		31,850,304
Convertible preferred stock, par value (in usd per share)		$ 0.001	$ 0.0001	$ 0.0001	$ 0.0001
Convertible preferred stock, price per share (in usd per share)		$ 4.00
Issuance of preferred stock \| $	$ 16,000,000	$ 16,000,000
Convertible preferred stock, liquidation rights per share (in usd per share)			4.00
Convertible preferred stock, dividend rate (in usd per share)			$ 0.32
Number of votes per share of common stock \| segment			10
Series 3 Preferred Stock \| Other Investors
Class of Stock [Line Items]
Other investors with a small percentage		0.02%
Series 3 Preferred Stock \| Nexperia
Class of Stock [Line Items]
Other investors with a small percentage		9.90%

Stockholders' Deficit - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands				1 Months Ended	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Dec. 23, 2020	Feb. 12, 2020	Feb. 27, 2020	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Feb. 11, 2020	Dec. 31, 2019	Dec. 31, 2018	Mar. 26, 2018
Class of Stock [Line Items]
Common stock, shares issued (in shares)	40,531,996		4,171,571		40,531,996		40,531,996	50,325,662	4,220,998
Common stock, shares outstanding (in shares)	40,278,496		4,171,571		40,278,496		40,278,496	50,325,662	4,220,998
Shares issued in connection with the Reverse Merger (in shares)			1,650,000
Total common and preferred stock authorized for issuance (in shares)									755,000,000
Common stock, shares authorized (in shares)	750,000,000				750,000,000		750,000,000		29,012,034
Common stock, par value (in usd per share)	$ 0.0001				$ 0.0001		$ 0.0001		$ 0.0001
Preferred stock, shares authorized (in shares)									23,946,403
Par Value Per Share (in usd per share)									$ 0.0001
Preferred stock, shares issued (in shares)	0				0		0
Preferred stock, shares outstanding (in shares)	0				0		0		23,933,949
Placement agent fees and closing expenses					$ 50		$ 3,100
Common Stock
Class of Stock [Line Items]
Common stock, shares outstanding (in shares)	40,531,996				40,531,996	35,135,520	40,278,496		4,220,998	4,219,606
Shares issued in connection with the Reverse Merger (in shares)						1,650,000	1,650,000
Shares redeemed (in shares)						52,773	52,773
Price per share (in dollars per share)			$ 4.00
Private Placement
Class of Stock [Line Items]
Placement agent fees and closing expenses				$ 1,800
Private Placement \| Common Stock
Class of Stock [Line Items]
Number of shares sold in private placement offering (in shares)	250,000	5,000,000		5,380,000
Price per share (in dollars per share)	$ 4.00	$ 3.00		$ 4.00	$ 4.00
Aggregate gross proceeds from closing of offering	$ 1,000	$ 15,000		$ 21,500
Placement agent fees and closing expenses	$ 50	$ 1,400
Exercise price (in usd per share)		$ 3.30
Private Placement \| Warrant
Class of Stock [Line Items]
Placement agent fees and closing expenses		$ 223
Number of common stock issuable from warrants (in shares)		150,000
Series 1 Preferred Stock
Class of Stock [Line Items]
Convertible preferred stock, shares issued (in shares)	0				0		0	51,680,254	12,433,953
Convertible preferred stock, shares outstanding (in shares)	0				0		0	51,680,254	12,433,953
Common stock, shares issued (in shares)			12,433,953
Common stock, shares outstanding (in shares)			12,433,953
Preferred stock, shares authorized (in shares)									12,438,704
Par Value Per Share (in usd per share)									$ 0.001
Preferred stock, shares outstanding (in shares)									12,433,953
Series 2 Preferred Stock
Class of Stock [Line Items]
Convertible preferred stock, shares issued (in shares)	0				0		0	38,760,190	7,499,996
Convertible preferred stock, shares outstanding (in shares)	0				0		0	38,760,190	7,499,996
Common stock, shares issued (in shares)			7,499,996
Common stock, shares outstanding (in shares)			7,499,996
Preferred stock, shares authorized (in shares)									7,507,699
Par Value Per Share (in usd per share)									$ 0.001
Preferred stock, shares outstanding (in shares)									7,499,996
Series 3 Preferred Stock
Class of Stock [Line Items]
Convertible preferred stock, shares issued (in shares)	0				0			31,850,304	4,000,000		4,000,000
Convertible preferred stock, shares outstanding (in shares)	0				0			31,850,304	4,000,000
Common stock, shares issued (in shares)			4,000,000
Common stock, shares outstanding (in shares)			4,000,000
Preferred stock, shares authorized (in shares)									4,000,000
Par Value Per Share (in usd per share)									$ 0.001
Preferred stock, shares outstanding (in shares)									4,000,000
Common Stock
Class of Stock [Line Items]
Common stock, shares outstanding (in shares)	40,531,996				40,531,996
Shares redeemed (in shares)			52,733
Common stock, shares authorized (in shares)	750,000,000				750,000,000		750,000,000		750,000,000
Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)	5,000,000				5,000,000		5,000,000		5,000,000

Stockholders' Deficit - Reserved Common Stock (Details)	Mar. 31, 2021 shares
Class of Stock [Line Items]
Common stock reserved for issuance (in shares)	5,198,440
Warrant
Class of Stock [Line Items]
Common stock reserved for issuance (in shares)	159,415
Stock options
Class of Stock [Line Items]
Common stock reserved for issuance (in shares)	5,039,025

Stockholders' Deficit - Warrants (Details) - $ / shares	Mar. 31, 2021	Feb. 12, 2020	Feb. 11, 2020
Class of Stock [Line Items]
Number of shares (in shares)	159,415	15,461	186,535
November 2020
Class of Stock [Line Items]
Number of shares (in shares)	6,046
Exercise price (in usd per share)	$ 34.74
February 2025
Class of Stock [Line Items]
Number of shares (in shares)	3,369
Exercise price (in usd per share)	$ 54.41
February 2025
Class of Stock [Line Items]
Number of shares (in shares)	150,000
Exercise price (in usd per share)	$ 3.30

Stock Based Compensation (Details) - shares	1 Months Ended		3 Months Ended		12 Months Ended
Stock Based Compensation (Details) - shares	Dec. 31, 2020	Sep. 30, 2020	Mar. 31, 2021	Sep. 30, 2020	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)			5,198,440
Percentage of outstanding shares			5.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			4 years
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)			5,039,025
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock granted (in shares)			137,452	816,180	816,180
Equity awards immediately vested (in shares)			3,000	4,000	4,000
Restricted Stock Units (RSUs) \| Period 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage vesting			33.33%
Restricted Stock Units (RSUs) \| Period 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage vesting			33.33%
Restricted Stock Units (RSUs) \| Period 3
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage vesting			33.33%
Restricted Stock Awards (RSA)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock granted (in shares)	12,000	123,501	0		135,501
Equity awards immediately vested (in shares)		98,450	37,051		98,450
Restricted Stock Awards (RSA) \| Period 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			120 days
The 2020 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)			1,560,503
Equity Awards outstanding under The 2020 Plan (in shares)			935,397
Number of shares authorized by 2020 plan (in shares)			5,050,000
The 2020 Equity Incentive Plan \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options authorized (in shares)			2,461,923
Annual increase in shares available for issue (in shares)			5,000,000
Transphorm Technology 2007 Stock Plan and 2015 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized by 2020 plan (in shares)			2,588,077

Stock Based Compensation - Schedule of Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended	12 Months Ended
	Jan. 01, 2020	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning balance, Options outstanding (in shares)	2,473,198	2,320,318	2,473,198	2,377,180
Options granted (in shares)		223,638	0	209,908
Options exercised (in shares)		(500)	(6,821)	(1,392)
Options cancelled (in shares)		(331)	(146,059)	(112,498)
Ending balance, Options outstanding (in shares)	2,473,198	2,543,125	2,320,318	2,473,198	2,377,180
Exercisable at period end (in shares)		2,283,243	2,267,154	2,079,809
Weighted Average Exercise Price per Share
Beginning of period (in dollars per share)	$ 4.67	$ 4.67	$ 4.67	$ 4.79
Options granted (in dollars per share)		6.37	0	3.14
Options exercised (in dollars per share)		3.14	3.78	3.86
Options cancelled (in dollars per share)		9.29	5.88	4.34
End of period (in dollars per share)	$ 4.67	4.82	4.67	4.67	$ 4.79
Exercisable at end of period (in usd per share)		$ 4.70	$ 4.70	$ 4.95
Weighted Average Remaining Contractual Term (in Years)
Options outstanding, weighted average remaining contractual term (in years)	6 years 10 months 2 days	6 years 18 days	5 years 11 months 1 day	6 years 10 months 2 days	7 years 5 months 15 days
Options exercisable, weighted average remaining contractual term (in years)		5 years 7 months 24 days	5 years 10 months 9 days	6 years 7 months 24 days
Aggregate Intrinsic Value (in thousands)
Options outstanding, aggregate intrinsic value	$ 0	$ 0	$ 0	$ 0	$ 0
Options exercisable, aggregate intrinsic value		$ 0	$ 0	$ 0
Closing stock price (in dollars per share)		$ 3.75	$ 3.00	$ 3.01

Stock Based Compensation - Fair Value Assumptions (Details) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average expected life (in years)	5 years 2 months 23 days	5 years 5 months 15 days
Risk-free interest rate, minimum	0.78%	1.34%
Risk-free interest rate, maximum	1.73%	1.94%
Expected volatility, minimum	43.10%	39.40%
Expected volatility, maximum	44.30%	39.80%
Grant date fair market value	$ 3.75	$ 3.01
Dividend yield	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value	$ 0.94	$ 0.98
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value	$ 1.65	$ 1.10

Stock Based Compensation - Restricted Stock (Details) - $ / shares	1 Months Ended		3 Months Ended		12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Mar. 31, 2021	Sep. 30, 2020	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Restricted stock at end of period (in shares)			(4,380)		(6,855)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted stock cancelled (in dollars per share)			$ 4,000.00		$ 4,000.00
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Restricted stock at beginning of period (in shares)			805,325		0
Restricted stock granted (in shares)			137,452	816,180	816,180
Restricted stock vested (in shares)			(3,000)	(4,000)	(4,000)
Restricted stock at end of period (in shares)	805,325		935,397		805,325
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted stock at beginning of period (in dollars per share)			$ 4,000.00		$ 0
Restricted stock granted (in dollars per share)			3,750		4,000.00
Restricted stock vested (in dollars per share)			3,750		4,000.00
Restricted stock at end of period (in dollars per share)	$ 4,000.00		$ 3,960		$ 4,000.00
Restricted Stock Awards (RSA)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Restricted stock at beginning of period (in shares)			37,051		0
Restricted stock granted (in shares)	12,000	123,501	0		135,501
Restricted stock vested (in shares)		(98,450)	(37,051)		(98,450)
Restricted stock at end of period (in shares)	37,051		0		37,051
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted stock at beginning of period (in dollars per share)			$ 4.00		$ 0
Restricted stock granted (in dollars per share)			0		3.91
Restricted stock vested (in dollars per share)			4.00		3.88
Restricted stock at end of period (in dollars per share)	$ 4.00		$ 0		$ 4.00

Stock Based Compensation - Share-based Payment Agreement, Expense (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock based compensation expense	$ 513	$ 132	$ 1,525	$ 566
Cost of revenue
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock based compensation expense	39	15	93	60
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock based compensation expense	115	46	306	196
Sales and marketing
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock based compensation expense	33	7	68	30
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock based compensation expense	$ 326	$ 64	$ 1,058	$ 280

Stock Based Compensation - Unrecognized Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Expense	$ 3,018	$ 2,741	$ 464
Average Expected Recognition Period	2 years 25 days	1 year 10 months 6 days	1 year 2 months 12 days
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options	$ 280	$ 54	$ 464
Average Expected Recognition Period	5 years 21 days	8 months 1 day	1 year 2 months 12 days
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock	$ 2,738	$ 2,687	$ 0
Average Expected Recognition Period	1 year 9 months 3 days	1 year 10 months 13 days

401(k) Savings Plan (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
401(k) Savings Plan (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Retirement Benefits [Abstract]
Employer discretionary contributions to 401K plan	$ 0	$ 0	$ 0	$ 0

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
Income Taxes (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Loss before tax expense	$ 6,579	$ 4,187	$ 17,909	$ 15,283
Tax expense	0	$ 0	0	0
Valuation allowance	53,500		52,200	49,400
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Loss before tax expense	4,900		10,300	10,600
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	250,000
Operating loss carryforwards subject to expiration	207,500
Domestic Tax Authority \| Tax Year 2019
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	8,800
Domestic Tax Authority \| Tax Year 2020
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	10,500
Domestic Tax Authority \| Tax Year 2021
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	4,500
Domestic Tax Authority \| Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Research tax credit carryforward	4,600
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	5,400
Foreign Tax Authority \| National Tax Agency, Japan
Operating Loss Carryforwards [Line Items]
Loss before tax expense	1,700		7,600	4,700
Foreign Tax Authority \| Transphorm Japan, Inc. \| National Tax Agency, Japan
Operating Loss Carryforwards [Line Items]
Loss before tax expense	1,500		800	1,000
Foreign Tax Authority \| Transphorm Ailzu, Inc. \| National Tax Agency, Japan
Operating Loss Carryforwards [Line Items]
Loss before tax expense			6,800	3,700
Foreign Tax Authority \| Transphorm Epi, Inc. \| National Tax Agency, Japan
Operating Loss Carryforwards [Line Items]
Loss before tax expense			(25)	(1)
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	153,500
Tax expense			$ 1	$ 1
State and Local Jurisdiction \| Tax Year 2018
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	18,500
State and Local Jurisdiction \| Tax Year 2019
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	2,300
State and Local Jurisdiction \| Tax Year 2020
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	2,600
State and Local Jurisdiction \| Tax Year 2021
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	1,000
State and Local Jurisdiction \| Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Research tax credit carryforward	$ 4,200

Income Taxes - Deferred Tax Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Net operating loss carryforwards	$ 47,424	$ 46,346	$ 43,973
Tax credits	5,444	5,262	4,535
California capitalized research and development	72	80	343
Fixed assets	0	8	0
Others, net	581	593	602
Total deferred tax assets	53,521	52,289	49,453
Valuation allowance	(53,481)	(52,289)	(49,403)
Deferred tax asset, net of valuation allowance	40	0	50
Deferred tax liabilities:
Others, net	0	0	0
Fixed assets	(40)	0	(50)
Total deferred tax liabilities	(40)	0	(50)
Net deferred tax assets	$ 0	$ 0	$ 0

Income Taxes - Effective Income Tax Rate Reconciliation (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Federal statutory income tax rate	21.00%	21.00%	21.00%
Research and development credit	2.73%	4.06%	4.76%
Nondeductible expense	(2.43%)	0.64%	(3.18%)
Loss in joint venture	(6.76%)	(11.70%)	(7.44%)
Foreign income tax rate difference	2.45%	4.10%	2.99%
Others, net	0.85%	(2.08%)	(0.75%)
Valuation allowance	(17.84%)	(16.02%)	(17.38%)
Effective tax rate	0.00%	0.00%	0.00%

Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Related Party Transaction
Accounts receivable due from related party	$ 14,100		$ 13,900	$ 5,800
Noncontrolling Common Stockholder
Related Party Transaction
Accounts receivable due from related party	5		17	38
Accounts payable to related party	370		512	272
Accrued Royalties, Related Party	4		100
Noncontrolling Common Stockholder \| Nexperia
Related Party Transaction
Accounts payable to related party	11		24
Noncontrolling Common Stockholder \| Research and development
Related Party Transaction
Related party transaction expenses				21
Noncontrolling Common Stockholder \| Sale of Products
Related Party Transaction
Revenue from related parties	12	$ 13	165	241
Noncontrolling Common Stockholder \| License Maintenance Fee
Related Party Transaction
Related party transaction expenses	54	50	200	200
Common Stockholder
Related Party Transaction
Revenue from related parties				504
Accounts receivable due from related party	503		435	426
Common Stockholder \| Reimbursement for research and development
Related Party Transaction
Revenue from related parties		177	408
Common Stockholder \| Sale of Products
Related Party Transaction
Revenue from related parties	304	344	915
Common Stockholder \| License Maintenance Fee
Related Party Transaction
Reduction in license maintenance fees	38		150
Common Stockholder \| License Fee Income
Related Party Transaction
Revenue from related parties	357	37	5,200	195
Common Stockholder \| Interest Expense
Related Party Transaction
Related party transaction expenses	150	152	610	608
Accounts receivable due from related party				9,200
Common Stockholder \| EPI Gen 4 wafer growth sales
Related Party Transaction
Revenue from related parties			701
Corporate Joint Venture
Related Party Transaction
Accounts receivable due from related party	13,500		13,500	5,300
Corporate Joint Venture \| Related Party Services
Related Party Transaction
Related party transaction expenses	406	111	241	211
Corporate Joint Venture \| Research and development
Related Party Transaction
Related party transaction expenses	144	245	919	695
Corporate Joint Venture \| Reimbursement for research and development
Related Party Transaction
Related party transaction expenses		177	408	195
Corporate Joint Venture \| Commitment For Services
Related Party Transaction
Related party transaction expenses		84	$ 84	444
Corporate Joint Venture \| Reimbursement from payroll related costs
Related Party Transaction
Related party transaction expenses	$ 9	$ 14		$ 14

Subsequent Events (Details) - USD ($)	Dec. 31, 2019	Mar. 31, 2019
Tranche B-1 Loan
Subsequent Event [Line Items]
Long-term loan facility	$ 2,000,000	$ 2,000,000