Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Summary of Stock Option Activity (Detail)

v3.10.0.1
Stock-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($)
$ / shares in Units, $ in Thousands
6 Months Ended 12 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]      
Number of shares, Outstanding, Beginning Balance 3,883,432    
Number of shares, Granted 83,625    
Number of shares, Exercised (333,899)    
Number of shares, Canceled (249,900)    
Number of shares, Outstanding, Ending Balance 3,383,258   3,883,432
Number of shares, Exercisable at March 31 , 2018 1,361,055    
Weighted average exercise price per share, Granted $ 23.03    
Weighted average exercise price per share, Exercised 3.72    
Weighted average exercise price per share, Canceled 13.29    
Weighted average exercise price per share outstanding 9.74   $ 9.16
Weighted average exercise price per share Exercisable $ 7.13    
Aggregate intrinsic value, Exercised $ 5,159 $ 0  
Aggregate intrinsic value, Outstanding 30,864   $ 49,965
Aggregate intrinsic value, Exercisable $ 15,977    
Weighted average remaining contractual life, Outstanding 8 years 4 months 24 days   8 years 9 months 18 days
Weighted average remaining contractual life, Exercisable 8 years