v3.10.0.1
Stock-Based Compensation - Other (Details)
$ / shares in Units, $ in Millions
6 Months Ended
Jun. 30, 2018
USD ($)
$ / shares
shares
Stock options  
Number of Options  
Outstanding balance at the beginning of the period (in shares) | shares 4,559,176
Granted (in shares) | shares 655,524
Exercised (in shares) | shares (501,531)
Forfeited (in shares) | shares (53,531)
Outstanding balance at the end of the period (in shares) | shares 4,659,638
Exercisable at the end of the period (in shares) | shares 3,201,819
Weighted Average Exercise Price per Share  
Outstanding balance at the beginning of the period (in dollars per share) | $ / shares $ 15.10
Granted (in dollars per share) | $ / shares 84.12
Exercised (in dollars per share) | $ / shares 9.56
Forfeited (in dollars per share) | $ / shares 35.69
Outstanding balance at the end of the period (in dollars per share) | $ / shares 25.17
Exercisable at the end of the period (in dollars per share) | $ / shares $ 11.26
Weighted Average Remaining Contractual Term (in years)  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term 4 years 8 months 23 days
Aggregate Intrinsic Value  
Exercisable at the end of the period | $ $ 231.5
Restricted Stock Units  
Summary of restricted stock unit activity  
Outstanding balance at the beginning of the period (in shares) | shares 1,413,423
Granted (in shares) | shares 440,818
Vested (in shares) | shares (517,050)
Forfeited (in shares) | shares (56,564)
Outstanding balance at the end of the period (in shares) | shares 1,280,627
Weighted-Average Grant-Date Fair value  
Outstanding at the beginning of the period (in dollars per share) | $ / shares $ 29.95
Granted (in dollars per share) | $ / shares 81.39
Vested (in dollars per share) | $ / shares 23.34
Forfeited (in dollars per share) | $ / shares 36.38
Outstanding at the end of the period (in dollars per share) | $ / shares $ 50.04