Financial Statements Details - Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018
Movement in Deferred Revenue [Roll Forward]
Deferred revenue, beginning balance	$ 448,644	$ 498,740
Less: Revenue recognized from beginning balance	(97,995)	(306,350)
Add: Deferral of revenue in current period, excluding amounts recognized during the period	179,206	337,465
Deferred revenue, ending balance	$ 529,855	$ 529,855