XML 55 R45.htm IDEA: XBRL DOCUMENT v3.20.2
Stock-Based Compensation - Schedule of Assumptions to Estimate Fair Value of Stock Options Using Black-Scholes Option Pricing Model (Details) - Stock Option - $ / shares
3 Months Ended 9 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Grant date fair value $ 13.53 $ 7.22 $ 16.61 $ 6.19
Expected term 5 years 10 months 24 days 6 years 6 years 6 years
Risk-free interest rate 0.40% 1.40% 1.20% 2.40%
Expected volatility 86.60% 81.60% 86.10% 79.10%
Dividend rate     0.00%