Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Stock Options - Additional Information (Detail)

v3.10.0.1
Stock-Based Compensation - Stock Options - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Weighted average grant date fair value for stock options granted $ 9.60 $ 2.17
Total fair value of stock options vested $ 2,500 $ 10,200
Aggregate intrinsic value of stock options exercised 6,416 $ 1,000
Total unrecognized stock-based compensation expense related to non-vested stock options $ 4,100  
Unrecognized stock-based compensation expense related to non-vested stock options period of recognition 3 years 7 months 6 days  
Dividend yield percentage 0.00% 0.00%
Minimum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock option, vesting period 2 years  
Maximum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock option, vesting period 6 years  
Acceleration Vesting [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Percentage of vesting 25.00%