| Document and Entity Information | Mar. 12, 2021 |
| Document Information [Line Items] | |
| Document Type | 8-K/A |
| Document Period End Date | Mar. 12, 2021 |
| Entity Registrant Name | Aeva Technologies, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-39204 |
| Entity Tax Identification Number | 84-3080757 |
| Entity Address, Address Line One | 555 Ellis Street |
| Entity Address, City or Town | Mountain View |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 94043 |
| City Area Code | 650 |
| Local Phone Number | 481-7070 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Amendment Description | Aeva Technologies, Inc. (the “Company”) is filing this Form 8-K/A (“Form 8-K/A” or “or this “Amendment””) to amend our Current Report on Form 8-K, originally filed with the Securities and Exchange Commission (the “SEC”) on March 18, 2021 (“Original Report”), to replace Exhibit 99.4 from the Original Report due to the restatement of InterPrivate Acquisition Corp., a Delaware corporation and our predecessor company (“InterPrivate”), financial statements and related footnote disclosures as of and for the year ended December 31, 2020.Restatement BackgroundOn March 12, 2021, Aeva, Inc. and InterPrivate, a special purpose acquisition company, closed their merger. Immediately following the merger, InterPrivate changed its name to Aeva Technologies, Inc.On April 12, 2021, the staff of the SEC issued a Staff Statement on Accounting and Reporting Considerations for Warrants Issued by Special Purpose Acquisition Companies (“SPACs”) (the “SEC Staff Statement”). In light of the SEC Staff Statement, the Company’s management further evaluated its private placement warrants under Accounting Standards Codification 815-40, Contracts in Entity’s Own Equity (“ASC 815-40”), which addresses equity versus liability treatment and classification of equity-linked financial instruments, including warrants, and states that a warrant may be classified as a component of equity only if, among other things, the warrant is indexed to the issuer’s common stock.Based on management’s evaluation, the Audit Committee of our Board of Directors, in consultation with management, concluded that the Company’s private placement warrants are not indexed to the Company’s common stock in the manner contemplated by ASC 815-40. As a result, the Company should have classified the private placement warrants as derivative liabilities measured at their estimated fair values at the end of each reporting period and recognized changes in the estimated fair value of the derivative instruments from the prior period in the Company’s operating results for the current period. |
| Entity Central Index Key | 0001789029 |
| Amendment Flag | true |
| Common Stock [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Common stock, par value $0.0001 per share |
| Trading Symbol | AEVA |
| Security Exchange Name | NYSE |
| Warrants to Purchase [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Warrants to purchase one share of common stock |
| Trading Symbol | AEVA.WS |
| Security Exchange Name | NYSE |
