Quarterly report pursuant to Section 13 or 15(d)

Stock Option and Incentive Plans - Assumptions to Compute Fair Value of Stock Option Grants (Detail)

v3.20.2
Stock Option and Incentive Plans - Assumptions to Compute Fair Value of Stock Option Grants (Detail)
3 Months Ended 9 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]        
Risk free interest rate 0.27% 1.58% 1.15% 2.35%
Expected term (in years) 6 years 1 month 13 days 5 years 6 months 29 days 6 years 10 days 6 years 21 days
Expected volatility 97.40% 90.60% 94.60% 89.70%