Quarterly report pursuant to Section 13 or 15(d)

Stock-based compensation - Narrative (Details)

v3.8.0.1
Stock-based compensation - Narrative (Details)
 1 Months Ended 3 Months Ended 9 Months Ended
Jun. 30, 2017
board_member
$ / shares
shares
Apr. 10, 2017
board_member
$ / shares
shares
Aug. 11, 2016
board_member
$ / shares
shares
Oct. 31, 2013
shares
Sep. 30, 2017
USD ($)
$ / shares
shares
Sep. 30, 2016
USD ($)
Sep. 30, 2017
USD ($)
$ / shares
shares
Sep. 30, 2016
USD ($)
Dec. 31, 2016
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Options outstanding (in shares)         2,142,035   2,142,035   1,857,012
Stock-based compensation | $             $ 743,928 $ 723,433  
Options outstanding, weighted-average grant date fair value (in dollars per share) | $ / shares         $ 1.39   $ 1.39   $ 1.65
Options granted, weighted-average grant date fair value (in dollars per share) | $ / shares             $ 0.86    
Number of shares granted (in shares)         0   960,000    
Restricted Stock                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Options outstanding (in shares)         875,000   875,000    
Number of shares granted (in shares)             410,000    
Stock Options                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Unrecognized compensation cost related to unvested stock-based awards | $         $ 1,300,000   $ 1,300,000    
Unrecognized compensation cost, recognition period             3 years 9 months 18 days    
Stock Options | General and Administrative Expense                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Stock-based compensation | $         $ 199,509 $ 343,505 $ 743,928 723,433  
The 2013 Plan                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Authorized shares (in shares)       4,773,992          
Shares remaining available for issuance (in shares)         1,675,207   1,675,207    
Contractual term       10 years          
Award vesting period       5 years          
Director                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Number of board members granted awards | board_member 4 1 4            
Number of shares granted (in shares) 19,139 22,167 15,267            
Director | Stock Options                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Stock-based compensation | $           $ 160,000 $ 205,000 $ 160,000  
Share price | $ / shares $ 2.17 $ 2.03 $ 2.62