Annual report pursuant to Section 13 and 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 ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Number of Options, Granted 0 0
Employee Stock Option [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Number of Options, Outstanding 1,037,239  
Number of Options, Granted 0  
Number of Options, Exercised (380,745)  
Number of Options, Forfeited 0  
Number of Options, Outstanding 656,494 1,037,239
Number of Options, Exercisable 656,494  
Weighted Average Exercise Price, Outstanding $ 4.80  
Weighted Average Exercise Price, Granted 0  
Weighted Average Exercise Price, Exercised 3.47  
Weighted Average Exercise Price, Forfeited 0  
Weighted Average Exercise Price, Outstanding 5.57 $ 4.80
Weighted Average Exercise Price, Exercisable $ 5.57  
Weighted Average Remaining Life In Years, Outstanding 4 years 7 months 6 days 6 years 4 months 24 days
Weighted Average Remaining Life In Years, Exercisable 4 years 7 months 6 days  
Intrinsic Value, Outstanding $ 252,887 $ 15,198,044
Intrinsic Value, Exercisable $ 252,887