Annual report pursuant to Section 13 and 15(d)

Stock options, warrants and restricted common stock (Schedule of Stock-based Compensation) (Details)

v3.19.1
Stock options, warrants and restricted common stock (Schedule of Stock-based Compensation) (Details) - USD ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Total stock-based compensation $ 4,660,406 $ 2,589,812
Restricted stock awards under Plan [Member]    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Total stock-based compensation 3,971,916 1,714,116
Stock option awards under Plan [Member]    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Total stock-based compensation $ 688,490 $ 875,696