Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Summary of RSU Activity (Detail)

v3.8.0.1
Stockholders' Equity - Summary of RSU Activity (Detail) - Unvested RSUs - $ / shares
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Shares, Unvested as of December 31, 2017 1,685,000  
Shares, Granted 642,487  
Shares, Forfeited (99,257)  
Shares, Vested (328,725)  
Shares, Unvested as of March 31, 2018 1,899,505  
Shares, Vested and unreleased 9,970  
Shares, Outstanding as of March 31, 2018 1,909,475  
Weighted Average Grant Date Fair Value, Unvested as of December 31, 2017 $ 16.90  
Weighted Average Grant Date Fair Value, Granted 35.80 $ 15.09
Weighted Average Grant Date Fair Value, Forfeited 17.10  
Weighted Average Grant Date Fair Value, Vested 15.10  
Weighted Average Grant Date Fair Value, Unvested as of March 31, 2018 $ 23.59