Employee Benefit Plans - Share Based Compensation by Cost and Expense Categories (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	$ 42.0	$ 33.9
Stock options
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	1.9	0.1
RSUs, RSAs, and PSAs
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	34.9	29.1
ESPP
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	5.2	4.7
Cost of revenues - Product
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	1.4	1.9
Cost of revenues - Service
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	4.2	4.5
Research and development
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	15.2	12.2
Sales and marketing
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	13.8	9.4
General and administrative
Stock Based Compensation Expense Recorded in Cost and Expense Categories
Share-based compensation expense	$ 7.4	$ 5.9