Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation - Estimated Fair Value of Stock Options (Details)

v3.20.4
Stock-Based Compensation - Estimated Fair Value of Stock Options (Details)
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected dividend yield 0.00%   0.00%
Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate 0.30% 1.70% 2.72%
Volatility 54.40% 52.90% 44.87%
Expected term (in years) 5 years 3 months 18 days 6 years 1 month 6 days 6 years 1 month 2 days
Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate 1.50% 2.59% 2.92%
Volatility 59.70% 55.07% 54.61%
Expected term (in years) 6 years 1 month 6 days 6 years 1 month 13 days 6 years 1 month 9 days