Stock-based Compensation - Additional Information (Detail)
12 Months Ended
Dec. 31, 2021
USD ($)
$ / shares
shares
Dec. 31, 2020
USD ($)
$ / shares
shares
Dec. 31, 2018
shares
Oct. 15, 2020
shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Share based payment exercise price description The exercise price for incentive stock options is at least 100% of the fair market value on the date of grant for stockholders owning less than 10% of the voting power of all classes of stock, or at least 110% of the fair market value for stockholders owning more than 10% of the voting power of all classes of stock. Options generally expire in 10 years and vest over periods determined by the Board, generally 48 months.      
Share based compensation expense | $ $ 13,457,000 $ 2,975,000    
Share based compensation expense recognized tax benefit | $ $ 0 $ 0    
Shares of common stock held by employees subject to repurchase 163,855 396,522    
Aggregate price for share repurchase | $ $ 300,000 $ 600,000    
Less than 10% [Member] | Minimum [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Exercise price for incentive stock options as of fair market value 1      
More Than 10% [Member] | Maximum [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Exercise price for incentive stock options as of fair market value 1.10      
Stock Option [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Expiration period 10 years      
Common stock vesting period 48 months      
Share based compensation expense | $ $ 12,200,000 $ 2,600,000    
Share based payment unamortised share based payment expenses | $ $ 33,600,000      
Share based payment expenses amortized over a weighted average period 2 years 6 months 21 days      
Share based payments weighted-average grant date fair value | $ / shares $ 13.76 $ 7.50    
Common stock issued upon exercise of stock options   371,939    
Restricted Stock [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Expiration period 3 years      
Share based compensation expense | $ $ 357,000 $ 361,000    
Share based payment unamortised share based payment expenses | $ $ 95,000      
Share based payment expenses amortized over a weighted average period 3 months 18 days      
Restricted stock awards rights vesting percentage 33.00%      
Restricted stock awards rights vesting 1/36      
Restricted stock awards granted     502,964  
2018 Equity incentive Plan [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Share based payment Common stock shares authorised 4,913,665      
Share based payment awards granted 4,279,693      
Common stock available for future grant 0      
2018 Equity incentive Plan [Member] | Restricted Stock [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Expiration period 4 years      
Restricted stock awards rights vesting percentage 25.00%      
Restricted stock awards rights vesting 1/48      
2020 Incentive Award Plan [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Share based payment awards granted 3,867,000      
Common stock available for future grant 2,637,000      
2020 Employee Stock Purchase Plan [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Common stock available for future grant 45,610     368,901
Share based compensation expense | $ $ 900,000