Summary of Significant Accounting Policies - Anti-Dilutive Securities Excluded from the Computation of Diluted Net Loss per Share (Detail) - shares shares in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2021 |
Sep. 30, 2020 |
Sep. 30, 2021 |
Sep. 30, 2020 |
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
| Anti-dilutive securities excluded from the computation of diluted loss per share | 10,805 | 8,227 | 10,805 | 8,227 |
| Common stock options [Member] | ||||
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
| Anti-dilutive securities excluded from the computation of diluted loss per share | 10,704 | 8,126 | 10,704 | 8,126 |
| Incentive awards [Member] | ||||
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
| Anti-dilutive securities excluded from the computation of diluted loss per share | 101 | 101 | 101 | 101 |