Equity Incentive Plan - Stock option (Details) - 2019 Plan and Company's 2010 Plan - USD ($)
$ / shares in Units, $ in Thousands |
3 Months Ended |
12 Months Ended |
Mar. 31, 2022 |
Dec. 31, 2021 |
| Number of Shares |
|
|
| Balance at beginning of period (in shares) |
7,162,676
|
|
| Granted (in shares) |
14,200
|
|
| Exercised (in shares) |
(16,666)
|
|
| Cancelled (in shares) |
(201,627)
|
|
| Balance at end of period (in shares) |
6,958,583
|
7,162,676
|
| Vested and expected to vest at end of period (in shares) |
6,958,583
|
|
| Exercisable at end of period (in shares) |
3,605,676
|
|
| Vested at end of period (in shares) |
3,587,710
|
|
| Weighted-Average Exercise Price |
|
|
| Balance at beginning of period (in dollars per share) |
$ 11.25
|
|
| Granted (in dollars per share) |
2.37
|
|
| Exercised (in dollars per share) |
4.56
|
|
| Cancelled (in dollars per share) |
10.19
|
|
| Balance at end of period (in dollars per share) |
11.28
|
$ 11.25
|
| Vested and expected to vest at end of period (in dollars per share) |
11.28
|
|
| Exercisable at end of period (in dollars per share) |
11.93
|
|
| Vested at end of period (in dollars per share) |
$ 11.96
|
|
| Weighted-Average Remaining Contractual Life |
|
|
| Weighted-average remaining contractual life of options (years) |
7 years 10 months 24 days
|
8 years 2 months 12 days
|
| Vested and expected to vest at end of period (in years) |
7 years 10 months 24 days
|
|
| Exercisable at end of period (in years) |
7 years 1 month 6 days
|
|
| Vested at end of period (in years) |
7 years 1 month 6 days
|
|
| Aggregate Intrinsic Value |
|
|
| Aggregate intrinsic value of options |
$ 34
|
$ 21
|
| Vested and expected to vest at end of period |
34
|
|
| Exercisable at end of period |
22
|
|
| Vested at end of period |
$ 22
|
|