Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Summary of RSU Activity (Detail)

v3.19.3
Stockholders' Equity - Summary of RSU Activity (Detail) - Unvested RSUs - $ / shares
9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Shares, Unvested as of December 31, 2018 1,405,460  
Shares, Granted 1,591,888  
Shares, Forfeited (435,266)  
Shares, Vested (560,864)  
Shares, Outstanding as of September 30, 2019 2,001,218  
Weighted Average Grant Date Fair Value, Unvested as of December 31, 2018 $ 26.94  
Weighted Average Grant Date Fair Value, Granted 27.04 $ 34.61
Weighted Average Grant Date Fair Value, Forfeited 30.16  
Weighted Average Grant Date Fair Value, Vested 23.89  
Weighted Average Grant Date Fair Value, Outstanding as of September 30, 2019 $ 27.17