Quarterly Selected Financial Data (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2021 |
Sep. 30, 2021 |
Jun. 30, 2021 |
Mar. 31, 2021 |
Dec. 31, 2020 |
Sep. 30, 2020 |
Jun. 30, 2020 |
Mar. 31, 2020 |
Dec. 31, 2019 |
Sep. 30, 2019 |
Jun. 30, 2019 |
Mar. 31, 2019 |
Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
|
| Quarterly Selected Financial Data (unaudited) | |||||||||||||||
| Operating Expenses | $ 6,810 | $ 9,047 | $ 11,290 | $ 11,483 | $ 9,879 | $ 9,845 | $ 10,767 | $ 13,269 | $ 38,630 | $ 43,760 | $ 48,854 | ||||
| Net income (loss) | $ (9,236) | $ (10,673) | $ (11,752) | $ (11,580) | |||||||||||
| Net income (loss) per share, basic | $ (0.20) | $ (0.24) | $ (0.28) | $ (0.34) | $ 0.92 | $ (0.33) | $ (0.36) | $ (0.44) | $ (1.03) | $ (0.20) | $ (1.59) | ||||
| Net income (loss) per share, diluted | $ (0.20) | $ (0.24) | $ (0.28) | $ (0.34) | $ 0.92 | $ (0.33) | $ (0.36) | $ (0.44) | $ (1.03) | $ (0.20) | $ (1.59) | ||||