Stock-Based Compensation - Stock-based compensation expense (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
|
| Stock-Based Compensation | |||
| Stock options | $ 549 | $ 1,956 | $ 1,458 |
| Restricted stock units | 120 | 1,083 | 474 |
| Deferred stock units | 206 | ||
| Total | $ 875 | $ 3,039 | $ 1,932 |