Stockholders' Equity - Stock-Based Compensation (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
---|---|---|---|---|
Jun. 30, 2021 |
Jun. 30, 2020 |
Jun. 30, 2021 |
Jun. 30, 2020 |
|
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Total stock-based compensation expense | $ 766 | $ 731 | $ 1,540 | $ 1,370 |
Research and development [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Total stock-based compensation expense | 158 | 161 | 319 | 305 |
General and administrative [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Total stock-based compensation expense | $ 608 | $ 570 | $ 1,221 | $ 1,065 |