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Stock Based Compensation - Fair Values of Stock Options Estimated Using Black-Scholes Valuation Model (Detail) - Employee Stock Option - $ / shares
3 Months Ended 6 Months Ended
Jun. 30, 2022
Jun. 30, 2021
Jun. 30, 2022
Jun. 30, 2021
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Black Scholes Method Used [Line Items]        
Risk-free rate 2.93% 0.96% 2.22% 0.74%
Expected term (in years) 6 years 5 years 8 months 12 days 6 years 6 years
Dividend yield 0.00% 0.00% 0.00% 0.00%
Volatility 91.82% 92.79% 91.63% 93.64%
Weighted-average fair value of stock options granted $ 0.87 $ 3.37 $ 0.55 $ 4.45