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)

v3.20.1
Stock-Based Compensation - Summary of Fair Values of Stock Options Granted and Assumptions used in Black-Scholes Model (Detail) - Stock Options [Member] - USD ($)
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Estimated fair values of stock options granted $ 5,190 $ 9,450
Risk-free interest rate 1.70% 2.50%
Expected volatility 77.40% 78.90%
Expected term (in years) 6 years 10 months 24 days 6 years 10 months 24 days