Annual report pursuant to Section 13 and 15(d)

EMPLOYEE STOCK OPTIONS AND RESTRICTED STOCK AWARD PLAN (Details Textual)

v3.8.0.1
EMPLOYEE STOCK OPTIONS AND RESTRICTED STOCK AWARD PLAN (Details Textual) - USD ($)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant   1,040,200  
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage 20.00%    
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options $ 3,741,997    
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition 2 years 6 months    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value $ 25,126,363    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value $ 19,884,600    
Share-based Compensation Arrangement by Share-based Payment Award, Per Share Weighted Average Price of Shares Purchased $ 13.90    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value $ 1,744,047 $ 65,089 $ 476,642
Share-based Compensation $ 3,685,079 $ 2,267,053 $ 2,566,716
Employee Stock Option [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period 165,400 26,500 65,000
Share-based Compensation $ 3,618,309 $ 2,267,053 $ 2,566,716
Restricted Stock [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage 20.00%    
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period 5 years    
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options $ 4,380,526    
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition 2 years    
Share-based Compensation $ 66,770