Supplemental Financial Information - Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) by Components (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 28, 2017	Jan. 30, 2016	Jan. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest and other income, net	$ 17,022	$ 17,685	$ 23,334
Research and development	(831,398)	(994,733)	(1,091,547)
Selling and marketing	(115,817)	(124,096)	(139,627)
General and administrative	(127,376)	(145,359)	(124,046)
Net Income (loss)	21,151	(811,400)	435,346
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net Income (loss)	2,444	(1,624)	515
Reclassification out of Accumulated Other Comprehensive Income | Marketable securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest and other income, net	1,911	586	1,245
Reclassification out of Accumulated Other Comprehensive Income | Auction rate securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest and other income, net	0	(2,274)	(512)
Reclassification out of Accumulated Other Comprehensive Income | Cash flow hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Research and development	467	48	(198)
Selling and marketing	10	(1)	(8)
General and administrative	$ 56	$ 17	$ (12)