Financial Statements Details - Other Income (Expense), Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Balance Sheet Components [Abstract]
Interest income	$ 8,585	$ 2,332	$ 21,933	$ 4,889
Unrealized loss on investments in privately-held companies, net	0	0	(9,100)	0
Others	707	(196)	(187)	(609)
Total	$ 9,292	$ 2,136	$ 12,646	$ 4,280