XML 87 R69.htm IDEA: XBRL DOCUMENT v3.19.1
Share-Based Compensation - Assumptions to estimate the fair value of options (Details) - Stock Options
12 Months Ended
Dec. 31, 2018
$ / shares
Dec. 31, 2017
$ / shares
Dec. 31, 2016
$ / shares
Share-Based Compensation      
Risk-free interest rate, minimum (in percent) 2.97% 2.26% 1.75%
Risk-free interest rate, maximum (in percent) 3.13% 2.57% 2.66%
Expected volatility, minimum (in percent) 46.23% 48.08% 49.63%
Expected volatility, maximum (in percent) 48.63% 49.35% 50.39%
Expected dividend yield (in percent) 0.00% 0.00% 0.00%
Exercise multiple 2.80 2.80 2.80
Post-vesting forfeit rate 0.00% 0.00% 0.00%
Fair value of underlying Ordinary Share, minimum (in dollars per share) $ 1.5146 $ 0.0858 $ 0.0308
Fair value of underlying Ordinary Share, maximum (in dollars per share) 5.7400 0.5359 0.0577
Fair value of share option, minimum 1.5091 0.0808 0.0273
Fair value of share option, maximum $ 5.7335 $ 0.5302 $ 0.0531