Share-based Compensation - Assumptions (Details) - Equity award – share options - $ / shares
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate, minimum 28.00% 180.00% 254.00%
Risk-free interest rate, maximum 146.00% 283.00% 3.18%
Expected term (in years) 10 years 10 years 10 years
Expected dividend yield 0.00% 0.00% 0.00%
Expected volatility, minimum 42.39% 47.54% 49.18%
Expected volatility, maximum 59.65% 50.01% 50.36%
Expected forfeiture rate (post-vesting) 300.00% 300.00% 300.00%
Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Exercise price (in dollars per share) $ 0.10 $ 0.10 $ 0.10
Fair value of the ordinary shares on the date of option grant (in dollars per share) 0.8415 0.6989 0.3493
Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Exercise price (in dollars per share) 1.74 0.50 1.00
Fair value of the ordinary shares on the date of option grant (in dollars per share) $ 8.9816 $ 1.4751 $ 0.6989