Derivative liabilities and redeemable convertible preferred stock liability - Additional Information (Detail) - USD ($)
 12 Months Ended
Oct. 19, 2020
Dec. 23, 2019
Dec. 31, 2021
Dec. 31, 2020
Aug. 16, 2018
Jun. 06, 2018
Apr. 20, 2018
Derivative Liabilities And Convertible Preferred Stock Liability [Line Items]              
Class of warrant or right, number of securities called by warrants or rights     134,112        
Percentage of principal amount of notes covered by warrants     25.00%        
Warrants issued expiry period     10 years        
Warrants issued closing date     Apr. 20, 2018        
Change in fair value       $ 757,000      
Preferred Stock, Shares Issued     0 0      
Derivative Financial Instruments, Liabilities [Member]              
Derivative Liabilities And Convertible Preferred Stock Liability [Line Items]              
Change in fair value       $ 296,000      
Derivative Financial Instruments, Liabilities [Member] | Warrant [Member]              
Derivative Liabilities And Convertible Preferred Stock Liability [Line Items]              
Fair value of warrants upon issuance           $ 238,000,000 $ 700,000
Mandatorily Redeemable Preferred Stock [Member]              
Derivative Liabilities And Convertible Preferred Stock Liability [Line Items]              
Redeemable convertible preferred stock liability at a fair value   $ 3,200,000          
Series A              
Derivative Liabilities And Convertible Preferred Stock Liability [Line Items]              
Warrants exercise price per share     $ 9.32        
Sale of stock issue price per share         $ 9.32    
Series B Two Preferred Stock [Member]              
Derivative Liabilities And Convertible Preferred Stock Liability [Line Items]              
Sale of Stock, Number of Shares Issued in Transaction 3,569,630 3,569,630          
Sale of stock issue price per share   $ 11.20563          
Change in fair value of liability       $ 11,400,000      
Maximum [Member]              
Derivative Liabilities And Convertible Preferred Stock Liability [Line Items]              
Warrants issued closing date     Jun. 06, 2018