Balance Sheet Components - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	$ 823,963
Net change, net of tax	(326)	$ 67
Balance, end of period	762,259
Unrealized Gains (Losses) on Cash Flow Hedges [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	66
Other comprehensive income (loss) before reclassifications	664
Amounts reclassified from AOCI	0
Net change, net of tax	664
Balance, end of period	730
Currency Translation Adjustments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	0
Other comprehensive income (loss) before reclassifications	0
Amounts reclassified from AOCI	0
Net change, net of tax	0
Balance, end of period	0
Unrealized Gains (Losses) on Available-for-Sale Investments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(75)
Other comprehensive income (loss) before reclassifications	(326)
Amounts reclassified from AOCI	0
Net change, net of tax	(326)
Balance, end of period	(401)
AOCI Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(9)
Other comprehensive income (loss) before reclassifications	338
Amounts reclassified from AOCI	0
Net change, net of tax	338
Balance, end of period	$ 329