Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Summary of Stock Option Activity (Detail)

v3.22.2.2
Stock-Based Compensation - Summary of Stock Option Activity (Detail) - 2012 Stock Option and Grant Plan [Member]
9 Months Ended 12 Months Ended
Sep. 30, 2021
$ / shares
shares
Dec. 31, 2020
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Number of Stock Options outstanding at January 1, 2021 | shares 19,618,953  
Number of Stock Options Granted | shares 4,676,898  
Number of Stock Options Exercised | shares (799,901)  
Number of Stock Options Forfeited, canceled, or expired | shares (1,325,349)  
Number of Stock Options outstanding at September 30, 2021 | shares 22,170,601 19,618,953
Number of Stock Options Vested and expected to vest at September 30, 2021 | shares 22,170,601  
Number of Stock Options Exercisable at September 30, 2021 | shares 10,895,186  
Weighted- Average Exercise Price Options outstanding at January 1, 2021 | $ / shares $ 1.78  
Weighted- Average Exercise Price Granted | $ / shares 4.9  
Weighted- Average Exercise Price Exercised | $ / shares 1.33  
Weighted- Average Exercise Price Forfeited, canceled, or expired | $ / shares 2.5  
Weighted- Average Exercise Price Options outstanding at September 30, 2021 | $ / shares 2.42 $ 1.78
Weighted- Average Exercise Price Vested and expected to vest at September 30, 2021 | $ / shares 2.42  
Weighted- Average Exercise Price Exercisable at September 30, 2021 | $ / shares $ 1.81  
Weighted- Average Remaining Contractual Term Options outstanding 7 years 6 months 7 years 10 months 24 days
Weighted- Average Remaining Contractual Term Vested and expected to vest at September 30, 2021 7 years 6 months  
Weighted- Average Remaining Contractual Term Exercisable at September 30, 2021 6 years 1 month 6 days