Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Summary of Stock Option Activity (Detail)

v3.8.0.1
Stockholders' Equity - Summary of Stock Option Activity (Detail) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]    
Outstanding, Shares, beginning balance 4,954,648  
Granted, Shares 719,950  
Exercised, Shares (309,497) 0
Forfeited or expired, Shares (173,276)  
Outstanding, Shares, ending balance 5,191,825  
Vested and expected to vest, Shares 5,191,825  
Exercisable, Shares 1,956,920  
Outstanding, Weighted Average Exercise Price, beginning balance $ 21.46  
Granted, Weighted Average Exercise Price 34.37  
Exercised, Weighted Average Exercise Price 20.02  
Forfeited or expired, Weighted Average Exercise price 32.72  
Outstanding, Weighted Average Exercise Price, ending balance 22.96  
Stock options vested and expected to vest, Weighted Average Exercise Price 22.96  
Exercisable, Weighted Average Exercise Price $ 24.63  
Outstanding, Weighted Average Remaining Contractual Term 5 years 2 months 12 days  
Stock options vested and expected to vest, Weighted Average Remaining Contractual Term 5 years 2 months 12 days  
Exercisable, Weighted Average Remaining Contractual Term 3 years 10 months 24 days  
Aggregate intrinsic value $ 85,253  
Vested and expected to vest, Aggregate Intrinsic Value 85,253  
Exercisable, Aggregate Intrinsic Value $ 30,000