Quarterly report pursuant to Section 13 or 15(d)

Stock Warrants - Additional Information (Detail)

v3.21.2
Stock Warrants - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 9 Months Ended
Jul. 14, 2021
Jan. 01, 2018
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2021
Sep. 30, 2020
Jun. 30, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2015
Common stock, Shares issued     185,697,959   185,697,959     39,510,108    
Warrants recognized liability at fair value         $ (170) $ 79        
Proceeds from Warrant Exercises         $ 550 $ 450        
Warrant [Member]                    
Warrants And Rights Exercised and Expiry Date         Sep. 24, 2029          
Common stock, Shares issued             179,572      
Private Placement [Member] | Warrant [Member]                    
Warrants recognized liability at fair value $ 5,700       $ 4,300          
Private Placement [Member] | Warrant [Member] | Fair value of derivative liabilities                    
Warrants recognized liability at fair value     $ 1,400   $ 1,400          
Public Warrant [Member]                    
Warrants recognized in Shareholder equity Fair Value $ 9,700                  
Loan Agreement [Member] | Right To Purchase Shares Of Common Stock [Member] | Warrant [Member]                    
Class of warrants and rights issued during period, Shares                   180,928
Class of warrants and rights, Exercise price of warrants and rights                   $ 0.06
Loan agreement termination date   Jan. 01, 2018                
Warrants and Rights Outstanding, Maturity Date     Feb. 17, 2025   Feb. 17, 2025          
Development Agreement [Member] | Right To Purchase Shares Series D Convertible Preferred Stock [Member] | Warrant [Member]                    
Class of warrants and rights issued during period, Shares                 280,528  
Class of warrants and rights, Exercise price of warrants and rights                 $ 0.00001  
Class of warrants of rights, Number of warrants or rights vested during period     19,036 0 110,212 70,130        
Class of warrants or rights non vested outstanding     0   0          
Increase or decrease derivative liabilities     $ 400   $ 600 $ 400