Annual report pursuant to Section 13 and 15(d)

Stock-based compensation - Narrative (Details)

v3.7.0.1
Stock-based compensation - Narrative (Details) - USD ($)
1 Months Ended 12 Months Ended
Sep. 19, 2016
Sep. 06, 2016
Apr. 08, 2016
Apr. 01, 2016
Feb. 27, 2016
Apr. 30, 2016
Oct. 31, 2013
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Stock-based compensation               $ 837,995 $ 811,658
Unrecognized compensation cost related to unvested stock-based awards               2,400,000 1,900,000
Fair value of options vested               1,460,228 918,424
General and Administrative Expense                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Stock-based compensation               $ 837,995 $ 811,658
Mr. Segal                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Number of options forfeited (in shares)         228,088        
Mr. Goldfinger                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Number of options forfeited (in shares)         114,044        
Employee Stock Option                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Granted (in shares) 30,000 30,000 1,000,000 250,000       560,000 0
Granted (in dollars per share) $ 2.39 $ 2.61 $ 2.73 $ 2.83       $ 2.72  
Number of options forfeited (in shares)               375,566  
Unrecognized compensation cost, recognition period               2 years 7 months 5 days  
Options granted, weighted-average grant date fair value (in dollars per share)               $ 1.65 $ 1.86
Employee Stock Option | Mr. Segal                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Granted (in shares)             1,022,104    
Granted (in dollars per share)             $ 5.00    
Employee Stock Option | Mr. Segal | Time Period                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Vesting rate (percent)             50.00%    
Employee Stock Option | Mr. Segal | Achievement of Targeted Annual Milestones                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Vesting rate (percent)             50.00%    
Employee Stock Option | Mr. Goldfinger                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Granted (in shares)             511,052    
Granted (in dollars per share)             $ 5.00    
Employee Stock Option | Mr. Goldfinger | Time Period                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Vesting rate (percent)             50.00%    
Employee Stock Option | Mr. Goldfinger | Achievement of Targeted Annual Milestones                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Vesting rate (percent)             50.00%    
Unrestricted Stock | Directors                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Stock-based compensation               $ 160,000 $ 160,000
Options Granted Upon Achievement of Certain Milestones                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Granted (in shares)     625,000 125,000          
Options Granted Upon Achievement of Certain Milestones | Key Executives                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Granted (in shares)               1,137,082  
2013 Employee, Director and Consultant Equity Incentive Plan                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Authorized shares (in shares)             4,773,992    
Contractual term             10 years    
Option vesting period             5 years    
Restricted Stock | Employee Stock Option                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Restricted stock granted (in shares)           787,500