Financial Statements Details - Other Income (Expense), Net (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Balance Sheet Components [Abstract]
Interest income	$ 13,107	$ 7,964	$ 25,005	$ 13,348
Interest expense	0	(680)	0	(1,367)
Gain (loss) on investment in privately-held companies	0	(9,100)	1,150	(9,100)
Other income (expense), net	704	(353)	(11)	(894)
Total other income (expense), net	$ 13,811	$ (2,169)	$ 26,144	$ 1,987