Annual report pursuant to Section 13 and 15(d)

Common Stock - Stock Warrants - Additional Information (Detail)

v3.20.4
Common Stock - Stock Warrants - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Jun. 30, 2019
May 30, 2019
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Jun. 19, 2018
Class of Warrant or Right [Line Items]            
Exercise price per unit of warrant           $ 80.00
Proceeds from exercise of warrants     $ 3,231 $ 4,199 $ 1,324  
Expected volatility     108.78% 94.25%    
Risk-free interest rate     0.94% 2.52%    
Expected term     6 years 5 years 11 months 19 days    
Common stock, shares issued     6,111,735 1,474,258    
New Warrant [Member]            
Class of Warrant or Right [Line Items]            
Fair value of warrants recognized into accumulated deficit $ (3,900)          
Stock price $ 84.6          
Expected volatility 97.16%          
Risk-free interest rate 2.06%          
Expected term 6 years          
Warrants Issued in December 2019 [Member]            
Class of Warrant or Right [Line Items]            
Warrants to purchase common stock     489,952      
Exercise price per unit of warrant     $ 6.6000      
Proceeds from exercise of warrants     $ 3,200      
Warrants Issued in October 2018 [Member]            
Class of Warrant or Right [Line Items]            
Warrants to purchase common stock       13,515    
Exercise price per unit of warrant     $ 62.8900 $ 62.89    
Proceeds from exercise of warrants       $ 800    
Warrants Issued in June 2018 [Member]            
Class of Warrant or Right [Line Items]            
Warrants to purchase common stock       41,875    
Exercise price per unit of warrant     $ 80.0000 $ 80.00    
Proceeds from exercise of warrants       $ 3,400    
Institutional Investor [Member]            
Class of Warrant or Right [Line Items]            
Proceeds from exercise of warrants   $ 4,200        
Institutional Investor [Member] | October 2018 Financing [Member]            
Class of Warrant or Right [Line Items]            
Warrants to purchase common stock   13,515        
Exercise price per unit of warrant   $ 62.89        
Institutional Investor [Member] | June 2018 Financing [Member]            
Class of Warrant or Right [Line Items]            
Warrants to purchase common stock   41,875        
Exercise price per unit of warrant   $ 80.00        
Institutional Investor [Member] | New Warrant [Member]            
Class of Warrant or Right [Line Items]            
Warrants to purchase common stock   60,000        
Exercise price per unit of warrant   $ 90        
Warrants, exercise period   6 years