Annual report pursuant to Section 13 and 15(d)

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

v3.20.1
Stock Option and Incentive Plans - Assumptions to Compute Fair Value of Stock Option Grants (Detail)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]      
Risk free interest rate 2.35% 2.58% 2.07%
Expected term (in years) 6 years 21 days 6 years 7 days 6 years 3 days
Expected volatility 89.70% 82.30% 79.60%