Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Summary of Estimated Weighted-Average Assumptions (Detail)

v3.20.4
Stockholders' Equity - Summary of Estimated Weighted-Average Assumptions (Detail) - USD ($)
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]      
Expected term (years) 6 years 5 years 10 months 24 days 4 years 7 months 6 days
Expected volatility 76.80% 76.10% 73.50%
Risk-free interest rate 0.80% 2.10% 2.70%
Expected dividend yield 0.00% 0.00% 0.00%
Weighted-average estimated grant date fair value per share $ 7.96 $ 18.06 $ 22.96
Options granted 2,641,125 2,535,425 2,998,650
Total estimated grant date fair value $ 21,023,000 $ 45,790,000 $ 68,849,000