Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.3
Stock Option and Incentive Plans - Assumptions to Compute Fair Value of Stock Option Grants (Detail)
3 Months Ended 9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]        
Risk free interest rate 1.58% 0.00% 2.35% 2.57%
Expected term (in years) 5 years 6 months 29 days 0 years 6 years 21 days 6 years 7 days
Expected volatility 90.60% 0.00% 89.70% 82.30%