Annual report pursuant to Section 13 and 15(d)

Share-based Compensation - Significant assumptions used in option pricing model (Details)

v3.21.1
Share-based Compensation - Significant assumptions used in option pricing model (Details) - Stock option awards
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected life (years) 5 years 5 years 6 months
Risk-free interest rate 0.30% 2.43%
Expected volatility 45.00% 45.00%