Annual report pursuant to Section 13 and 15(d)

Stock and Employee Benefit Plans - Additional Information (Detail)

v3.7.0.1
Stock and Employee Benefit Plans - Additional Information (Detail) - USD ($)
 1 Months Ended 12 Months Ended
Jun. 29, 2016
Jun. 30, 2016
Dec. 31, 2016
Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]        
Cash received from option exercises     $ 0 $ 10,000
Common stock, par value     $ 0.001 $ 0.001
Stock based compensation expense     $ 1,905,256 $ 1,164,633
Research and Development [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Stock based compensation expense     599,138 $ 379,066
Newly Hired Executive [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Number of options granted       500,000
Newly Hired Executive [Member] | Research and Development [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Stock based compensation expense     $ 300,000 $ 100,000
2014 Stock Plan [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Number of options granted 0   1,157,734 755,329
Weighted-average price of options     $ 1.57  
Weighted-average remaining contractual life     8 years 6 months 18 days 9 years 2 months 1 day
Number of shares, Forfeited     140,000  
2014 Stock Plan [Member] | Newly Hired Executive [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Number of options granted     500,000 450,000
Common stock, par value       $ 0.001
Stock based compensation expense       $ 0
Weighted-average price of options     $ 3.36  
Weighted-average remaining contractual life     8 years 7 months 17 days  
2016 Stock Plan [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Common shares authorized for issuance   3,750,000    
Stock options vesting period   4 years    
Maximum term of stock options     10 years  
Number of options granted     715,313 0
Weighted-average price of options     $ 2.36  
Weighted-average remaining contractual life     9 years 7 months 13 days 0 years
Common stock available for grant     3,124,687  
Number of shares, Forfeited     90,000  
2016 Stock Plan [Member] | Newly Hired Executive [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Number of options granted     500,000  
Weighted-average price of options     $ 1.45  
Weighted-average remaining contractual life     9 years 10 months 28 days  
2016 Stock Plan [Member] | Newly Hired Executive [Member] | Research and Development [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Stock based compensation expense     $ 10,998  
2016 Stock Plan [Member] | Employees Consultants And Directors [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Number of options granted     265,313  
401 (k) Plan [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Contributions employee benefit plans     $ 31,670 $ 3,013