Business	12 Months Ended
Business	Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business	Business The original Transphorm, Inc., now named Transphorm Technology, Inc. (“Transphorm Technology”), a wholly owned subsidiary of Parent (as defined below), was founded in 2007 to develop gallium nitride (“GaN”) semiconductor components used in power conversion. On February 12, 2020 (the “Closing Date”), Peninsula Acquisition Corporation (“Peninsula”), a shell company, consummated the Agreement and Plan of Merger and Reorganization (the “Merger Agreement”) dated February 12, 2020, by and among Peninsula, Peninsula Acquisition Sub, Inc., a Delaware corporation and wholly owned subsidiary of Peninsula (“Merger Sub”), and Transphorm Technology. Pursuant to the terms of the Merger Agreement, Merger Sub merged with and into Transphorm Technology, with Transphorm Technology surviving the merger as a wholly-owned subsidiary of Peninsula (the “Merger”). On the Closing Date, Peninsula changed its name to Transphorm, Inc. (“Parent”). 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. (“TPJ”) was established in Japan in February 2014 to secure the Company’s production capacity and establish a direct presence in Asian markets. Transphorm Aizu, Inc. (“Transphorm Aizu”) was established in Japan to manage the financial transactions around Aizu Fujitsu Semiconductor Wafer Solution Limited (“AFSW”), the wafer fabrication facility located in Aizu Wakamatsu, Japan that is owned by GaNovation, the joint venture company in which the Company has a non-controlling interest. Transphorm Japan Epi, Inc. (“TJE”) was established in Japan in 2019 to enable the operational capacity of the MOCVD reactors held in Aizu. Going Concern The accompanying consolidated financial statements have been prepared assuming that the Company will continue as a going concern. However, considering the Company’s working capital (including restricted cash) of $8.8 million as of March 31, 2023, the Company’s historical losses from operations (during the year ended March 31, 2023, the Company used $26.5 million in cash from operations), and the future expected losses, there is 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. In April 2023, the Company raised gross proceeds of $7.3 million from the exercise of warrants and $2.0 million from selling shares of our common stock in a private placement, but also used $12.2 million of cash to repay our revolving loan with Nexperia when it matured on April 4, 2023, and as such did not alleviate the 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. In response to the factors noted above, management intends to raise additional working capital to fund operations through the issuance of stock to investors (including in the form of a rights offering as noted in “Note 19 - Subsequent Events” to the Consolidated Financial Statements), issuance of debt (including through the Company’s asset-based debt financing initiatives), and/or license of intellectual property. However, there is no assurance that the Company will be successful in raising additional capital. If the Company is unable to secure additional funding, the Company believes that its existing cash and cash equivalents and forecasted revenue will be sufficient to fund its operations into the second half of September 2023. If the Company does not obtain any other financing, the Company would need to cease operations, liquidate its assets, and may seek the protection of applicable bankruptcy laws. The Company’s ability to sustain operations is dependent on its ability to successfully market and sell its products and its ability to raise capital through additional financings until it is able to achieve profitability with positive cash flows. 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 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.