Acquired Intangible Assets Net (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jul. 28, 2012		Jan. 28, 2012
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amounts	$ 382,590		$ 383,431
Accumulated Amortization	(268,463)		(241,926)
Net Carrying Amount	114,127		141,505
Purchased technology
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amounts	103,490		103,490
Accumulated Amortization	(59,867)		(50,906)
Net Carrying Amount	43,623		52,584
Purchased technology | Minimum
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Lives	2 years 6 months
Purchased technology | Maximum
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Lives	7 years
Core technology
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amounts	178,000		178,000
Accumulated Amortization	(153,208)		(142,932)
Net Carrying Amount	24,792		35,068
Core technology | Minimum
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Lives	6 years
Core technology | Maximum
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Lives	8 years
Trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Lives	5 years
Gross Carrying Amounts	1,500		1,500
Accumulated Amortization	(374)		(232)
Net Carrying Amount	1,126		1,268
Customer contracts
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amounts	89,900		89,900
Accumulated Amortization	(55,014)		(47,856)
Net Carrying Amount	34,886		42,044
Customer contracts | Minimum
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Lives	5 years
Customer contracts | Maximum
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Lives	7 years
In-process research and development
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Lives		[1]
Gross Carrying Amounts	9,700		10,541
Net Carrying Amount	$ 9,700		$ 10,541

[1] Upon completion of the project, the related in-process research and development ("IPR&D") assets will be amortized over its estimated useful life. If any of the projects are abandoned or the forecast of the project indicates that the fair value is less than the carrying amount, the Company will be required to write down the related IPR&D asset.