Summary of Significant Accounting Policies - Anti-dilutive Securities (Details) - shares shares in Thousands |
9 Months Ended | |
|---|---|---|
Sep. 30, 2021 |
Sep. 30, 2020 |
|
| Common stock options | ||
| Anti-dilutive securities excluded from computations of diluted weighted-average common shares outstanding | ||
| Potentially dilutive securities excluded from computations of diluted weighted-average shares outstanding (in shares) | 14,518 | 13,047 |
| Unvested restricted stock and RSUs | ||
| Anti-dilutive securities excluded from computations of diluted weighted-average common shares outstanding | ||
| Potentially dilutive securities excluded from computations of diluted weighted-average shares outstanding (in shares) | 1,069 | 853 |
| Convertible debt securities | ||
| Anti-dilutive securities excluded from computations of diluted weighted-average common shares outstanding | ||
| Potentially dilutive securities excluded from computations of diluted weighted-average shares outstanding (in shares) | 23,438 | 11,492 |