XML 66 R57.htm IDEA: XBRL DOCUMENT v3.20.4
Share-based Compensation - Schedule of share based payment award stock options valuation assumptions (Detail) - $ / shares
9 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected dividends yield 0.00% 0.00%
Expected term (in years) 6 years 6 years
Minimum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected volatility 48.90% 46.50%
Risk-free interest rate 0.30% 2.10%
Fair value of underlying ordinary share (US$) $ 16.00 $ 6.35
Maximum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected volatility 52.20% 46.90%
Risk-free interest rate 1.69% 2.60%
Fair value of underlying ordinary share (US$) $ 42.31 $ 7.29