Stock-Based Compensation - Summary and Allocation of Stock-Based Compensation Expense (Details) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]    
Stock-based compensation expense $ 9,232 $ 5,647
Tax benefit 1,529 985
Stock-based compensation expense related to employee equity awards and employee stock purchases, net of tax 7,703 4,662
Cost of sales - product    
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]    
Stock-based compensation expense 955 640
Cost of sales - service    
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]    
Stock-based compensation expense 1,308 961
Cost of revenues    
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]    
Stock-based compensation expense 2,263 1,601
Sales and marketing    
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]    
Stock-based compensation expense 2,613 391
Research and development    
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]    
Stock-based compensation expense 2,573 1,042
General and administrative    
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]    
Stock-based compensation expense 1,783 2,613
Operating Expenses    
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]    
Stock-based compensation expense $ 6,969 $ 4,046