Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Stock Option Activity (Detail)

v3.19.1
Stockholders' Equity - Stock Option Activity (Detail) - USD ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2018
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of shares, Options vested and expected to vest   1,110,501    
Number of shares, Forfeited   (25,000)    
Number of shares, Options vested and expected to vest 1,085,501      
Number of shares, Options Exercisable     1,085,501  
Number of shares, Options outstanding     1,085,501  
Weighted average exercise price, Forfeited   $ 4.75    
Weighted average exercise price, Options vested and expected to vest $ 3.75      
Weighted average exercise price, Options vested and exercisable     $ 3.75  
Weighted average exercise price, Options outstanding $ 3.75   $ 3.75 $ 3.78
Total Weighted average intrinsic value, Options vested and expected to vest   $ 1,351,080    
Weighted average remaining contractual life (years), Options vested and expected to vest 2 years 11 months 5 days 3 years 11 months 12 days    
Weighted average remaining contractual life (years), Exercisable as of December 31, 2018 2 years 11 months 5 days      
Weighted average remaining contractual life (years), Options vested and exercisable 2 years 11 months 5 days