0001715768 2020-01-01 2020-12-31 0001715768 2020-12-31 0001715768 2021-02-28 iso4217:USD shares 0001715768 2020 FY true 10-K/A true 2020-12-31 --12-31 false 000-55832 Transphorm, Inc. DE 82-1858829 75 Castilian Drive Goleta, CA 93117 805 456-1300 No No Yes Yes Non-accelerated Filer true true false false false 0 40278796 None. Transphorm, Inc. (“we,” “us,” “our,” the “Company,” or “Transphorm”) is filing this Amendment No. 1 on Form 10-K/A (“Amendment No. 1”) to amend our Annual Report on Form 10-K for the fiscal year ended December 31, 2020 (“Original Filing”), filed with the U.S. Securities and Exchange Commission (“SEC”) on March 12, 2021 (“Original Filing Date”), to include the information required by Items 10 through 14 of Part III of Form 10-K. This information was previously omitted from the Original Filing in reliance on General Instruction G(3) to Form 10-K. Pursuant to Rule 12b-15 under the Securities Exchange Act of 1934, as amended, this Amendment No. 1 also contains new certifications by our principal executive officer and principal financial officer as required by Section 302 of the Sarbanes-Oxley Act of 2002. Accordingly, Item 15 of Part IV is amended to include the currently dated certifications as exhibits.Except as expressly noted in this Amendment No. 1, this Amendment No. 1 does not reflect events that may have occurred subsequent to the Original Filing Date or modify or otherwise update any other disclosures contained in the Original Filing, including, without limitation, the financial statements. Accordingly, this Amendment No. 1 should be read in conjunction with the Original Filing.