Annual report pursuant to Section 13 and 15(d)

Stock Based Compensation (Details)

v3.6.0.2
Stock Based Compensation (Details)
 3 Months Ended 12 Months Ended
May 18, 2016
USD ($)
Grant
shares
Mar. 31, 2016
USD ($)
$ / shares
shares
Dec. 31, 2016
USD ($)
$ / shares
shares
Dec. 31, 2015
USD ($)
$ / shares
shares
Dec. 31, 2014
USD ($)
$ / shares
shares
Annual share reserve increase (as a percent)     4.00%    
Total stock-based compensation     $ 1,694,891 $ 394,748  
Option Activity, Number of shares          
Balance, beginning of period | shares   959,188 959,188 552,726  
Granted | shares     915,242 523,390  
Forfeitures | shares     (25,071) (116,928)  
Balance, end of period | shares     1,849,359 959,188 552,726
Vested or expected to vest | shares     1,849,359    
Exercisable | shares     791,251    
Option Activity, Weighted-average exercise price          
Beginning of period | $ / shares   $ 7.68 $ 7.68 $ 9.17  
Granted | $ / shares     3.35 6.31  
Forfeitures | $ / shares     5.04 8.60  
End of period | $ / shares     5.57 $ 7.68 $ 9.17
Vested or expected to vest | $ / shares     5.57    
Exercisable | $ / shares     $ 7.55    
Option Activity, Fair value of options granted          
Granted     $ 2,155,234 $ 1,467,886  
Option Activity, Weighted-average remaining contractual term (in years)          
Balance     8 years 5 months 9 days    
Vested or expected to vest     8 years 5 months 9 days    
Exercisable     7 years 2 months 27 days    
Aggregate intrinsic value     $ 0    
Fair value of options vested in period       $ 700,000 $ 1,300,000
Per share weighted average fair value of options granted | $ / shares     $ 2.35 $ 2.80 $ 2.24
Fair value assumptions          
Expected term of options (in years)         6 years 3 months
Expected stock price volatility       70.00% 70.00%
Expected annual dividend yield     0.00% 0.00% 0.00%
Unrecognized compensation expense          
2017     $ 815,654    
2018     766,151    
2019     357,279    
2020     108,716    
Total     2,047,800    
Research and development expense          
Total stock-based compensation     141,247 $ 67,021  
General and administrative          
Total stock-based compensation     1,553,644 $ 327,727  
Stock options          
Option Activity, Weighted-average remaining contractual term (in years)          
Fair value of options vested in period     $ 400,000    
Minimum          
Fair value assumptions          
Risk-free interest rate     1.01% 1.64% 0.85%
Expected term of options (in years)     5 years 5 years 5 years
Expected stock price volatility     80.00%    
Maximum          
Fair value assumptions          
Risk-free interest rate     1.93% 1.97% 1.97%
Expected term of options (in years)     6 years 3 months 6 years 3 months  
Expected stock price volatility     100.00%    
2016 Plan          
Increase in number of shares reserved for issuance | shares 600,000        
Common stock remaining for future issuance (in shares) | shares     666,069    
2015 Plan          
Number of grants to be made | Grant 0        
Common stock remaining for future issuance (in shares) | shares 464,476        
2011 Stock Incentive Plan          
Number of grants to be made | Grant 0        
Employee Stock Purchase Plan (ESPP)          
Common stock remaining for future issuance (in shares) | shares     480,000    
Total stock-based compensation     $ 70,890    
Unrecognized compensation expense          
Percentage of fair market value on the lower of first day or last day of the offering period at which employees may purchase stock under the ESPP 85.00%        
Maximum portion of earning an employee may contribute to the ESPP Plan 15.00%        
Maximum annual amount of fair market value of the Company's common stock that a participant may accrue the rights to purchase $ 25,000        
Shares of common stock for future issuance | shares 500,000        
Chief Executive Officer | General and administrative          
Total stock-based compensation   $ 781,266