Quarterly report pursuant to Section 13 or 15(d)

Common Stock - Common Stock Warrants - Additional Information (Detail)

v3.19.3
Common Stock - Common Stock Warrants - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
 9 Months Ended
May 30, 2019
Sep. 30, 2019
Sep. 30, 2018
Dec. 31, 2018
Jun. 19, 2018
May 23, 2018
Class of Warrant or Right [Line Items]            
Common stock, par value   $ 0.001   $ 0.001   $ 0.001
Exercise price per unit of warrant         $ 4.00  
Proceeds from aggregate warrant exercise   $ 4,199 $ 1,274      
Expected volatility   94.25% 88.23%      
Risk-free interest rate   2.52% 2.93%      
Expected term   5 years 11 months 19 days 5 years 8 months 4 days      
New Warrant [Member]            
Class of Warrant or Right [Line Items]            
Fair value of warrants recognized into accumulated deficit   $ (3,900)        
Stock price   $ 4.23        
Expected volatility   97.16%        
Risk-free interest rate   2.06%        
Expected term   6 years        
Warrants Issued In June 2018 [Member]            
Class of Warrant or Right [Line Items]            
Exercise price per unit of warrant   $ 4.0000 $ 4.00      
Proceeds from aggregate warrant exercise   $ 3,400 $ 500      
Number of warrants exercised   837,500 130,500      
Warrants Issued in October 2018 [Member]            
Class of Warrant or Right [Line Items]            
Exercise price per unit of warrant   $ 3.1445        
Proceeds from aggregate warrant exercise   $ 800        
Number of warrants exercised   270,313        
Armistice [Member]            
Class of Warrant or Right [Line Items]            
Proceeds from aggregate warrant exercise $ 4,200          
Armistice [Member] | October 2018 Financing [Member]            
Class of Warrant or Right [Line Items]            
Warrants to purchase common stock 270,313          
Common stock, par value $ 0.001          
Exercise price per unit of warrant $ 3.1445          
Armistice [Member] | June 2018 Financing [Member]            
Class of Warrant or Right [Line Items]            
Warrants to purchase common stock 837,500          
Exercise price per unit of warrant $ 4.00          
Armistice [Member] | New Warrant [Member]            
Class of Warrant or Right [Line Items]            
Warrants to purchase common stock 1,200,000          
Exercise price per unit of warrant $ 4.50          
Warrants, exercise period 6 years