Other Financial Information - Notes Receivable and Deposit, Revenue, Deferred Commissions Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2014
Disaggregation of Revenue [Line Items]
Proceeds from pulse note receivable	$ 0	$ 0	$ 75,000,000.0
Non-interest bearing deposit to contract manufacturer	23,600,000	25,000,000.0
Non-interest bearing deposit to contract manufacturer, unamortized discount	$ 2,600,000	$ 1,100,000
Non-interest bearing deposit to contract manufacturer, imputed interest rate	5.00%	4.80%
Deposit assets	$ 48,600,000
Impairment charge, notes receivable	0	$ 0	0
Deferred commission	24,100,000	33,700,000
Amortization of deferred commission	130,900,000	144,200,000
Impairment loss	0
Product
Disaggregation of Revenue [Line Items]
Contract with customer, liability, revenue recognized	68,600,000
Service
Disaggregation of Revenue [Line Items]
Contract with customer, liability, revenue recognized	706,800,000
Junos Pulse
Disaggregation of Revenue [Line Items]
Promissory note				$ 125,000,000.0
Proceeds from pulse note receivable			75,000,000.0
Interest income	$ 10,400,000	$ 8,400,000	$ 8,300,000