Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Summary of RSU Activity (Detail)

v3.19.2
Stockholders' Equity - Summary of RSU Activity (Detail) - Unvested RSUs - $ / shares
6 Months Ended
Jun. 30, 2019
Jun. 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 998,567  
Shares, Forfeited (346,327)  
Shares, Vested (526,489)  
Shares, Unvested as of June 30, 2019 1,531,211  
Shares, Vested and unreleased 0  
Shares, Outstanding as of June 30, 2019 1,531,211  
Weighted Average Grant Date Fair Value, Unvested as of December 31, 2018 $ 26.94  
Weighted Average Grant Date Fair Value, Granted 35.17 $ 36.69
Weighted Average Grant Date Fair Value, Forfeited 29.37  
Weighted Average Grant Date Fair Value, Vested 23.69  
Weighted Average Grant Date Fair Value, Unvested as of June 30, 2019 $ 32.87