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Stock Plans and Stock-Based Compensation - Performance-Based Restricted Stock Units - Additional Information (Details) - USD ($)
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Stock-based compensation expense $ 7,785,000 $ 6,694,000
Unrecognized compensation expense $ 16,500,000  
Weighted-average amortization period 2 years 2 months 4 days  
Number of stock units vested 0  
Performance-Based Restricted Stock Units    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Share-based compensation, number of stock unit grants in period 81,655  
Stock-based compensation expense $ 1,900,000 $ 0
Award achievement probability percentage 100.00%  
Performance-Based Restricted Stock Units | Minimum    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Share-based compensation, thresholds percentage of revenue growth 20.00%  
Share price $ 54.83  
Performance-Based Restricted Stock Units | Maximum    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Share-based compensation, thresholds percentage of revenue growth 40.00%  
Share price $ 64.86  
Performance-Based Restricted Stock Units | Tranche One    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Share-based compensation, compounded annual growth measurement period 2 years  
Share-based compensation, vesting stock percentage 50.00%  
Performance-Based Restricted Stock Units | Tranche Two    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Share-based compensation, compounded annual growth measurement period 3 years