Financial Statements Details - Contract Balances (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Change in Contract with Customer, Asset [Roll Forward]
Contract assets, beginning balance	$ 5,699	$ 0	$ 6,341	$ 0
Contract assets, ending balance	1,668	6,959	1,668	6,959
Change in Contract with Customer, Liability [Roll Forward]
Contract liabilities, beginning balance	37,314	18,838	32,595	16,521
Less: Revenue recognized from beginning balance	(3,552)	(1,933)	(6,766)	(4,070)
Less: Beginning balance reclassified to deferred revenue	(1,593)	(906)	(1,205)	(731)
Add: Contract liabilities recognized	9,857	5,843	17,402	10,122
Contract liabilities, ending balance	42,026	$ 21,842	42,026	$ 21,842
Other Current Liabilities
Change in Contract with Customer, Liability [Roll Forward]
Contract liabilities, beginning balance			13,500
Contract liabilities, ending balance	$ 16,700		$ 16,700