Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation (Details)

v3.19.1
Stock Based Compensation (Details)
 1 Months Ended 3 Months Ended 12 Months Ended
Apr. 15, 2019
installment
day
award
$ / shares
shares
Apr. 01, 2019
$ / shares
shares
Jan. 01, 2017
shares
May 18, 2016
shares
Apr. 05, 2016
USD ($)
shares
May 31, 2018
shares
Mar. 31, 2019
USD ($)
$ / shares
shares
Mar. 31, 2018
USD ($)
Dec. 31, 2018
day
$ / shares
shares
Annual share reserve increase (as a percent)             4.00%    
Total stock-based compensation | $             $ 596,693 $ 242,824  
Research and development                  
Total stock-based compensation | $             57,376 11,497  
General and administrative                  
Total stock-based compensation | $             489,953 207,382  
Sales and marketing                  
Total stock-based compensation | $             $ 49,364 $ 23,945  
Service Based Options                  
Option Activity, Number of shares                  
Balance, beginning of period (in shares)   3,845,305         3,746,597    
Granted (in shares)             134,379    
Options exercises in period (in shares)             (31,288)    
Forfeitures (in shares)             (4,383)    
Balance, end of period (in shares)             3,845,305   3,746,597
Exercisable (in shares)             2,269,081    
Option Activity, Weighted-average exercise price                  
Beginning of period (in dollars per share) | $ / shares   $ 4.19         $ 4.16    
Granted (in dollars per share) | $ / shares             4.78    
Exercised (in dollars per share) | $ / shares             3.01    
Forfeitures (in dollars per share) | $ / shares             4.25    
End of period (in dollars per share) | $ / shares             4.19   $ 4.16
Exercisable (in dollars per share) | $ / shares             $ 4.56    
Option Activity, Fair value of options granted                  
Grant date fair value of options granted | $             $ 334,624    
Grant date fair value of options forfeited | $             $ 11,297    
Option Activity, Weighted-average remaining contractual term (in years)                  
Balance             7 years 7 months 10 days   7 years 9 months 15 days
Exercisable             6 years 9 months 4 days    
Aggregate intrinsic value of options outstanding | $             $ 8,100,000    
Aggregate intrinsic value of options exercisable | $             4,600,000    
Intrinsic value of options exercised | $             100,000    
Fair value of options vested in period | $             $ 600,000    
Per share weighted average fair value of options granted (in dollars per share) | $ / shares             $ 2.49    
Options vested (in shares)             302,901    
Options vested weighted average grant date fair value (in dollars per share) | $ / shares             $ 2.09    
Compensation not yet recognized | $             $ 3,100,000    
Period for recognition             2 years 10 months 24 days    
Fair value assumptions                  
Expected dividend yield             0.00%    
Expected volatility             55.00%    
Stock Options With Market Based Vesting Conditions                  
Option Activity, Number of shares                  
Balance, beginning of period (in shares)   500,000         500,000    
Granted (in shares)             0    
Balance, end of period (in shares)             500,000   500,000
Exercisable (in shares)             0    
Option Activity, Weighted-average exercise price                  
Beginning of period (in dollars per share) | $ / shares   $ 4.24         $ 4.24    
Granted (in dollars per share) | $ / shares                
End of period (in dollars per share) | $ / shares             $ 4.24   $ 4.24
Option Activity, Weighted-average remaining contractual term (in years)                  
Balance             8 years 11 months 27 days   9 years 2 months 27 days
Aggregate intrinsic value of options outstanding | $             $ 800,000    
Compensation not yet recognized | $             $ 805,068    
Period for recognition             1 year 9 months 18 days    
Market-based vesting condition share price floor (in dollars per share) | $ / shares                 $ 12.50
Market-based vesting condition number of consecutive days | day                 3
Restricted Stock Awards                  
Award vesting period                 4 years
Total stock-based compensation | $             $ 118,656    
Compensation not yet recognized | $             $ 1,433,329    
Option Activity, Weighted-average remaining contractual term (in years)                  
Period for recognition             3 years    
RSUs outstanding                  
Beginning balance of Non-vested RSAs (in shares)   345,000         445,000    
RSAs vested (in shares)             (100,000)    
Ending balance of Non-vested RSAs (in shares)             345,000   445,000
Weighted average grant date fair value                  
Nonvested RSAs weighted average grant date fair value (in dollars per share) | $ / shares             $ 4.27   $ 4.27
RSAs vested in period weighted average grant date fair value (in dollars per share) | $ / shares             $ 4.24    
Minimum | Service Based Options                  
Fair value assumptions                  
Expected life (in years)             5 years    
Risk-free interest rate             2.23%    
Maximum | Service Based Options                  
Fair value assumptions                  
Expected life (in years)             6 years 3 months    
Risk-free interest rate             2.59%    
2016 Plan                  
Increase in number of shares reserved for issuance (in shares)       600,000   1,400,000.0      
Common stock remaining for future issuance (in shares)             2,100,000    
2016 Plan | Stock options                  
Award expiration period             10 years    
2015 Plan                  
Common stock remaining for future issuance (in shares)       464,476          
Employee Stock Purchase Plan (ESPP)                  
Common stock remaining for future issuance (in shares)             1,192,025    
Total stock-based compensation | $             $ 35,298    
Weighted average grant date fair value                  
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%        
Increase in shares available (in shares)     408,042            
Employee | 2016 Plan | Minimum | Stock options                  
Award vesting period             3 years    
Employee | 2016 Plan | Maximum | Stock options                  
Award vesting period             4 years    
Director | 2016 Plan | Stock options                  
Award vesting period             3 years    
Subsequent Event | Employee | Service Based Options                  
Award vesting period   36 months              
Option Activity, Number of shares                  
Granted (in shares)   1,800,000.0              
Option Activity, Weighted-average exercise price                  
Granted (in dollars per share) | $ / shares   $ 6.22              
Subsequent Event | Board of Directors Chairman | Service Based Options                  
Award vesting period 24 months                
Option Activity, Number of shares                  
Granted (in shares) 300,000                
Option Activity, Weighted-average exercise price                  
Granted (in dollars per share) | $ / shares $ 5.17                
Subsequent Event | Board of Directors Chairman | Stock Options With Market Based Vesting Conditions                  
Option Activity, Number of shares                  
Granted (in shares) 300,000                
Subsequent Event | Board of Directors Chairman | Restricted Stock Awards                  
RSUs outstanding                  
RSAs vested (in shares) (50,000)                
Weighted average grant date fair value                  
Grants in period (in shares) 250,000                
Number of vesting installments | installment 3                
Number of awards | award 2                
Tranche One | Subsequent Event | Employee | Service Based Options                  
Option Activity, Weighted-average exercise price                  
Share-based Compensation Arrangement By Share-based Payment Award, Awards Vesting, Percent   25.00%              
Tranche One | Subsequent Event | Board of Directors Chairman | Service Based Options                  
Option Activity, Weighted-average exercise price                  
Share-based Compensation Arrangement By Share-based Payment Award, Awards Vesting, Percent 33.00%                
Tranche One | Subsequent Event | Board of Directors Chairman | Stock Options With Market Based Vesting Conditions                  
Option Activity, Weighted-average remaining contractual term (in years)                  
Market-based vesting condition share price floor (in dollars per share) | $ / shares $ 8.00                
Market-based vesting condition number of consecutive days | day 3                
Tranche Two | Subsequent Event | Employee | Service Based Options                  
Option Activity, Weighted-average exercise price                  
Share-based Compensation Arrangement By Share-based Payment Award, Awards Vesting, Percent   75.00%              
Tranche Two | Subsequent Event | Board of Directors Chairman | Service Based Options                  
Option Activity, Weighted-average exercise price                  
Share-based Compensation Arrangement By Share-based Payment Award, Awards Vesting, Percent 67.00%                
Tranche Two | Subsequent Event | Board of Directors Chairman | Stock Options With Market Based Vesting Conditions                  
Option Activity, Weighted-average remaining contractual term (in years)                  
Market-based vesting condition share price floor (in dollars per share) | $ / shares $ 10.50                
Market-based vesting condition number of consecutive days | day 3                
Tranche Three | Subsequent Event | Board of Directors Chairman | Stock Options With Market Based Vesting Conditions                  
Option Activity, Weighted-average remaining contractual term (in years)                  
Market-based vesting condition share price floor (in dollars per share) | $ / shares $ 13.00                
Market-based vesting condition number of consecutive days | day 3