The Company and Summary of Significant Accounting Policies - Components of the Finished ASRs (Details) - USD ($) $ in Thousands |
Dec. 31, 2022 |
Dec. 31, 2021 |
|---|---|---|
| The Company and Summary of Significant Accounting Policies | ||
| ASRs on lease or available for lease | $ 9,002 | $ 6,489 |
| Demonstration ASRs | 622 | 585 |
| Research and development ASRs | 194 | 320 |
| Charge boxes | 380 | 301 |
| Finished ASRs, gross | 10,198 | 7,695 |
| Less: accumulated depreciation | (7,853) | (6,192) |
| Finished ASRs, net | $ 2,345 | $ 1,503 |