v3.19.3
Stockholders' Equity - Additional Information (Details)
shares in Millions, $ in Millions
9 Months Ended 12 Months Ended
Sep. 30, 2019
USD ($)
Plan
shares
Dec. 31, 2018
shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Number of share-based employee compensation plans | Plan 3  
Pre-2017 RSUs    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Unrecognized compensation cost $ 60.4  
Weighted average recognition period 1 year  
Post-2017 RSUs    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Unrecognized compensation cost $ 1,400.0  
Weighted average recognition period 3 years  
Service condition satisfied, years 4 years  
Post-2017 RSUs | First Year    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Award vesting percentage 10.00%  
Post-2017 RSUs | Second Year    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Award vesting percentage 20.00%  
Post-2017 RSUs | Third Year    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Award vesting percentage 30.00%  
Post-2017 RSUs | Fourth Year    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Award vesting percentage 40.00%  
RSUs    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
RSUs vested but not yet settled | shares 13.7 22.4
RSAs    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Unrecognized compensation cost $ 80.0  
Weighted average recognition period 3 years 6 months  
Stock Options    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Weighted average recognition period 2 years  
Unrecognized compensation cost related to stock options $ 23.0