Quarterly report pursuant to Section 13 or 15(d)

Assumptions Used in Estimating Fair Value of Stock Options Granted (Detail)

v3.20.2
Assumptions Used in Estimating Fair Value of Stock Options Granted (Detail)
3 Months Ended 9 Months Ended
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions And Methodology [Abstract]      
Expected term (years) 6 years 1 month 6 days 5 years 6 months 6 years 1 month 6 days
Volatility 85.40% 102.80% 85.40%
Risk-free interest rate 2.60% 0.37% 2.60%