Net Loss Per Common Share - Computation of Potentially Anti-dilutive Securities (Detail) - shares
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Potentially dilutive securities that were not included in the diluted per share calculations 5,879,131 4,213,738 3,209,915
Options Issued and Outstanding and ESPP Shares Issuable and Outstanding [Member]      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Potentially dilutive securities that were not included in the diluted per share calculations 5,170,331 4,213,738 3,179,041
Early Exercised Common Stock Subject To Future Vesting [Member]      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Potentially dilutive securities that were not included in the diluted per share calculations 0 0 30,874
Restricted Stock Subject to Future Vesting [Member]      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Potentially dilutive securities that were not included in the diluted per share calculations 708,800 0 0