CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Jan. 28, 2017	Jan. 30, 2016	Jan. 31, 2015
Income Statement [Abstract]
Net revenue	$ 2,317,674	$ 2,649,216	$ 3,637,206
Operating costs and expenses:
Cost of goods sold	1,029,527	1,442,517	1,799,425
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
Carnegie Mellon University litigation settlement	0	654,667	0
Restructuring and other related charges	105,186	53,251	10,438
Amortization and write-off of acquired intangible assets	8,376	10,098	15,747
Total operating costs and expenses	2,217,680	3,424,721	3,180,830
Operating income (loss)	99,994	(775,505)	456,376
Interest and other income, net	17,022	17,685	23,334
Income (loss) from continuing operations before income taxes	117,016	(757,820)	479,710
Provision (benefit) for income taxes	73,022	11,335	(4,077)
Income (loss) from continuing operations	43,994	(769,155)	483,787
Loss from discontinued operations, net of tax	(22,843)	(42,245)	(48,441)
Net Income (loss)	$ 21,151	$ (811,400)	$ 435,346
Net income (loss) per share - Basic:
Continuing operations (in usd per share)	$ 0.09	$ (1.51)	$ 0.95
Discontinued operations (in usd per share)	(0.05)	(0.08)	(0.10)
Net Income (loss) per share basic (in usd per share)	0.04	(1.59)	0.85
Net income (loss) per share - Diluted:
Continuing operations (in usd per share)	0.09	(1.51)	0.93
Discontinued operations (in usd per share)	(0.05)	(0.08)	(0.09)
Net Income (loss) per share diluted (in usd per share)	$ 0.04	$ (1.59)	$ 0.84
Weighted average shares:
Basic (in shares)	509,738	510,945	511,089
Diluted (in shares)	517,513	510,945	520,760
Cash dividends declared per share (in usd per share)	$ 0.24	$ 0.24	$ 0.24