Stock-Based Compensation - Assumptions Used For Stock Options (Details) - Stock option awards - $ / shares |
6 Months Ended | |
|---|---|---|
Jun. 30, 2020 |
Jun. 30, 2019 |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Weighted average grant-date fair value per share (in dollars per share) | $ 1.16 | $ 4.77 |
| Expected term (in years) | 6 years | 6 years |
| Expected stock volatility | 86.00% | 46.00% |
| Dividend yield | 0.00% | 0.00% |
| Risk-free interest rate | 1.00% | 2.40% |