| Cover | Mar. 10, 2022 |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Mar. 10, 2022 |
| Entity File Number | 001-39959 |
| Entity Registrant Name | CEPTON, INC. |
| Entity Central Index Key | 0001498233 |
| Entity Tax Identification Number | 27-2447291 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 399 West Trimble Road |
| Entity Address, City or Town | San Jose |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 95131 |
| City Area Code | 408 |
| Local Phone Number | 459-7579 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Elected Not To Use the Extended Transition Period | false |
| Common stock, par value $0.00001 per share | |
| Title of 12(b) Security | Common stock, par value $0.00001 per share |
| Trading Symbol | CPTN |
| Security Exchange Name | NASDAQ |
| Redeemable warrants, exercisable for common stock at an exercise price of $11.50 per share, subject to adjustment | |
| Title of 12(b) Security | Redeemable warrants, exercisable for common stock at an exercise price of $11.50 per share, subject to adjustment |
| Trading Symbol | CPTNW |
| Security Exchange Name | NASDAQ |
