Stock-based Compensation - Summary of Stock Option Activity (Details)
$ / shares in Units, $ in Thousands |
6 Months Ended |
|
Jun. 30, 2020
USD ($)
$ / shares
shares
|
|---|
| Number of Shares |
|
| Outstanding at beginning of period (in shares) | shares |
7,296,746
|
| Granted (in shares) | shares |
80,100
|
| Exercised (in shares) | shares |
0
|
| Forfeited (in shares) | shares |
(56,609)
|
| Expired (in shares) | shares |
(521,317)
|
| Outstanding at end of period (in shares) | shares |
6,798,920
|
| Vested and expected to vest at end of period (in shares) | shares |
6,774,447
|
| Vested and exercisable at end of period (in shares) | shares |
5,871,832
|
| Weighted Average Exercise Price |
|
| Outstanding at beginning of period (in dollars per share) | $ / shares |
$ 2.48
|
| Granted (in dollars per share) | $ / shares |
1.51
|
| Exercised (in dollars per share) | $ / shares |
0
|
| Forfeited (in dollars per share) | $ / shares |
2.14
|
| Expired (in dollars per share) | $ / shares |
2.60
|
| Outstanding at end of period (in dollars per share) | $ / shares |
2.46
|
| Vested and expected to vest at end of period (in dollars per share) | $ / shares |
2.46
|
| Vested and exercisable at end of period (in dollars per share) | $ / shares |
$ 2.52
|
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures |
|
| Weighted average remaining contractual term (in years), outstanding |
5 years 2 months 4 days
|
| Weighted average remaining contractual term (in years), vested and expected to vest |
5 years 1 month 28 days
|
| Weighted average remaining contractual term (in years), vested and exercisable |
4 years 8 months 23 days
|
| Aggregate intrinsic value, outstanding | $ |
$ 0
|
| Aggregate intrinsic value, vested and expected to vest | $ |
0
|
| Aggregate intrinsic value, vested and exercisable | $ |
$ 0
|