Annual report pursuant to Section 13 and 15(d)

Stock Based Compensation (Details)

v3.19.1
Stock Based Compensation (Details)
 1 Months Ended 3 Months Ended 12 Months Ended
Jan. 01, 2019
$ / shares
shares
May 18, 2016
USD ($)
grant
shares
May 31, 2018
shares
Sep. 30, 2018
USD ($)
Dec. 31, 2018
USD ($)
$ / shares
shares
Dec. 31, 2017
USD ($)
$ / shares
shares
Annual share reserve increase (as a percent)         4.00%  
Total stock-based compensation | $         $ 2,431,063 $ 1,157,252
Fair value assumptions            
Expected annual dividend yield         0.00%  
Research and development            
Total stock-based compensation | $         $ 101,000 156,047
General and administrative            
Total stock-based compensation | $         2,135,710 1,001,205
Sales and marketing            
Total stock-based compensation | $         $ 194,353 $ 0
Service Based Options            
Option Activity, Number of shares            
Balance, beginning of period (in shares) 3,746,597       2,823,489  
Granted (in shares)         1,639,860  
Options exercises in period (in shares)         (243,115)  
Forfeitures (in shares)         (473,637)  
Balance, end of period (in shares)         3,746,597 2,823,489
Exercisable (in shares)         1,997,468  
Option Activity, Weighted-average exercise price            
Beginning of period (in dollars per share) | $ / shares $ 4.16       $ 3.93  
Granted (in dollars per share) | $ / shares         3.85  
Forfeitures (in dollars per share) | $ / shares         2.77  
End of period (in dollars per share) | $ / shares         4.16 $ 3.93
Vested or expected to vest (in dollars per share) | $ / shares         1.87  
Exercisable (in dollars per share) | $ / shares         $ 4.71  
Option Activity, Fair value of options granted            
Grant date fair value of options granted | $         $ 3,737,728  
Grant date fair value forfeitures | $         $ 1,109,083  
Option Activity, Weighted-average remaining contractual term (in years)            
Balance         7 years 9 months 15 days 7 years 3 months 15 days
Exercisable         6 years 7 months 13 days  
Aggregate intrinsic value | $         $ 1,500,000  
Aggregate intrinsic value of options exercisable | $         1,000,000  
Intrinsic value of options exercised | $         500,000  
Fair value of options vested in period | $         $ 1,200,000 $ 2,900,000
Per share weighted average fair value of options granted (in dollars per share) | $ / shares         $ 2.28 $ 0.66
Options vested (in shares)         641,286  
Unrecognized compensation expense | $         $ 3,062,257  
Unrecognized compensation cost period for recognition         3 years 1 month 6 days  
Market Based Options            
Option Activity, Number of shares            
Balance, beginning of period (in shares) 500,000       0  
Granted (in shares)         500,000  
Balance, end of period (in shares)         500,000 0
Exercisable (in shares)         0  
Option Activity, Weighted-average exercise price            
Beginning of period (in dollars per share) | $ / shares $ 4.24          
Granted (in dollars per share) | $ / shares         $ 4.24  
End of period (in dollars per share) | $ / shares         $ 4.24  
Option Activity, Fair value of options granted            
Grant date fair value of options granted | $         $ 1,260,000  
Option Activity, Weighted-average remaining contractual term (in years)            
Balance         9 years 2 months 27 days  
Aggregate intrinsic value | $         $ 0  
Per share weighted average fair value of options granted (in dollars per share) | $ / shares         $ 2.52  
Unrecognized compensation expense | $         $ 917,568  
Unrecognized compensation cost period for recognition         2 years 18 days  
Fair value assumptions            
Risk-free interest rate         2.84%  
Expected term of options (in years)         2 years 9 months 18 days  
Expected stock price volatility         60.00%  
Expected annual dividend yield         0.00%  
Restricted Stock            
Total stock-based compensation | $         $ 346,514  
Option Activity, Weighted-average remaining contractual term (in years)            
Unrecognized compensation cost period for recognition         3 years 3 months 18 days  
Restricted Stock Award, Number of Shares            
Nonvested restricted, beginning balance (in shares) 445,000       0  
Granted (in shares)         445,000  
Nonvested restricted, ending balance (in shares)         445,000 0
Restricted Stock Award Weighted Average Grant Date Fair Value [Abstract]            
Weighted average grant date fair value (in dollars per share) | $ / shares         $ 4.27  
Restricted stock award unrecognized compensation expense | $         $ 1,551,986  
Minimum | Service Based Options            
Fair value assumptions            
Risk-free interest rate         2.51% 1.85%
Expected term of options (in years)         5 years 5 years
Expected stock price volatility         55.00% 55.00%
Expected annual dividend yield         0.00% 0.00%
Maximum | Service Based Options            
Fair value assumptions            
Risk-free interest rate         3.01% 2.38%
Expected term of options (in years)         6 years 3 months 6 years 3 months
Expected stock price volatility         65.00% 100.00%
Expected annual dividend yield         0.00% 0.00%
2016 Plan            
Increase in number of shares reserved for issuance (in shares)   600,000 1,400,000      
Common stock remaining for future issuance (in shares)         602,657  
2016 Plan | Stock options            
Award expiration period         10 years  
2015 Plan            
Number of grants to be made | grant   0        
Common stock remaining for future issuance (in 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)         783,983  
Total stock-based compensation | $         $ 49,863 $ 76,305
Restricted Stock Award Weighted Average Grant Date Fair Value [Abstract]            
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 (in shares)   500,000        
Automatic increase to shares authorized as percentage of outstanding stock at end of preceding year   1.00%        
Employee | 2016 Plan | Stock options            
Award vesting period         4 years  
Director | 2016 Plan | Stock options            
Award vesting period         3 years  
Terminated Executive            
Total stock-based compensation | $       $ 322,000    
Subsequent Event | 2016 Plan            
Increase in number of shares reserved for issuance (in shares) 1,632,167          
Shares available for issuance 2,234,824