Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Summary of Fair Values of Stock Options Granted and Assumptions used in Black-Scholes Model (Detail)

v3.21.2
Stock-Based Compensation - Summary of Fair Values of Stock Options Granted and Assumptions used in Black-Scholes Model (Detail) - Stock Options [Member] - $ / shares
9 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Estimated fair values of stock options granted $ 3.93 $ 3.32
Minimum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Risk-free interest rate 0.60% 0.30%
Expected volatility 80.10% 77.40%
Expected term (in years) 5 years 6 months 6 years
Maximum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Risk-free interest rate 1.10% 1.70%
Expected volatility 82.00% 81.20%
Expected term (in years) 6 years 6 months 10 years