Quarterly report pursuant to Section 13 or 15(d)

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

v3.8.0.1
Stock-Based Compensation - Stock Options - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Weighted average grant date fair value for stock options granted $ 10.39  
Total fair value of stock options vested $ 475,000 $ 0
Aggregate intrinsic value of stock options exercised 3,260 $ 0
Total unrecognized stock-based compensation expense related to non-vested stock options $ 3,700  
Unrecognized stock-based compensation expense related to non-vested stock options period of recognition 4 years 3 months 19 days  
Granted, options (in shares) 79,875 0
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%