Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Summary of RSU Activity (Detail)

v3.20.4
Stockholders' Equity - Summary of RSU Activity (Detail) - Unvested RSUs - $ / shares
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Shares, Unvested as of December 31, 2019 1,910,764    
Shares, Granted 3,973,991    
Shares, Forfeited (836,190)    
Shares, Vested (1,218,945)    
Shares, Outstanding as of December 31, 2020 3,829,620 1,910,764  
Weighted Average Grant Date Fair Value, Unvested as of December 31, 2019 $ 26.93    
Weighted Average Grant Date Fair Value, Granted 12.19 $ 27.04 $ 36.83
Weighted Average Grant Date Fair Value, Forfeited 18.39    
Weighted Average Grant Date Fair Value, Vested 19.34    
Weighted Average Grant Date Fair Value, Outstanding as of December 31, 2020 $ 15.91 $ 26.93