Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Additional Information (Detail)

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Stock-Based Compensation - Additional Information (Detail) - USD ($)
 3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Stock Based Compensation [Line Items]        
Stock based compensation expense $ 649,948 $ 446,113 $ 1,962,018 $ 1,426,341
Cash received from option exercises     $ 366,200  
Weighted average grant date fair value $ 3.34 $ 1.05 $ 2.02 $ 1.01
2016 Stock Plan [Member]        
Stock Based Compensation [Line Items]        
Number of shares, Options granted   114,378   114,378
Stock options vesting period     4 years  
Common stock available for grant 1,951,052   1,951,052  
Number of shares, Forfeited     218,467  
Number of shares, Options exercised 46,930   121,392  
Cash received from option exercises $ 0   $ 147,950  
Maximum term of stock options     10 years  
2016 Stock Plan [Member] | Employees Consultants And Directors [Member]        
Stock Based Compensation [Line Items]        
Number of shares, Options granted 148,306   1,407,061  
2016 Stock Plan [Member] | Newly-Hired Executive Officer [Member]        
Stock Based Compensation [Line Items]        
Number of shares, Options granted 450,000      
Stock based compensation expense $ 54,270   $ 54,270  
2014 Stock Plan [Member]        
Stock Based Compensation [Line Items]        
Number of shares, Options granted 0   0  
Number of shares, Forfeited     14,958  
Number of shares, Options exercised 95,625   110,625  
Cash received from option exercises $ 188,250   $ 218,250  
2014 Stock Plan [Member] | Employees Consultants And Directors [Member]        
Stock Based Compensation [Line Items]        
Number of shares, Options granted   0   1,157,734