Income Taxes - Deferred tax assets net (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2021 |
|
| Deferred tax assets: | |||
| Net operating loss carryforwards | $ 42,344 | $ 42,486 | $ 52,539 |
| Tax credit carryforwards | 7,894 | 6,990 | 9,181 |
| Capitalized tax assets | 63 | 125 | |
| Capitalized tax assets | (3) | ||
| Accruals | 207 | 152 | 137 |
| Stock compensation | 4,942 | 4,317 | 5,006 |
| Operating lease liability | 646 | 892 | 1,021 |
| Other | 47 | 40 | 12 |
| Total deferred tax assets | 56,143 | 54,874 | 68,021 |
| Deferred tax liabilities | |||
| Operating lease right-of-use asset | (461) | (651) | (893) |
| Valuation allowance | (55,682) | (54,223) | (67,128) |
| Net deferred tax assets | 0 | 0 | $ 0 |
| Increase in valuation allowance | $ 11,400 | $ 1,500 | |