Goodwill and Intangible Assets - Schedule Of Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands		6 Months Ended
		Jul. 26, 2015	Jan. 25, 2015
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount		$ 181,049	$ 169,048
Accumulated amortization		(83,883)	(71,448)
Net carrying amount		97,166	97,600
Core Technologies [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount		144,156	134,155
Accumulated amortization		(63,440)	(53,286)
Net carrying amount		$ 80,716	80,869
Core Technologies [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life		2 years
Core Technologies [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life		10 years
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount		$ 30,030	28,030
Accumulated amortization		(13,647)	(11,480)
Net carrying amount		$ 16,383	16,550
Customer Relationships [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life		7 years
Customer Relationships [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life		10 years
Technology Licenses [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	[1]	$ 263	263
Accumulated amortization	[1]	(196)	(169)
Net carrying amount	[1]	$ 67	94
Technology Licenses [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life		5 years
Technology Licenses [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life		10 years
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount		$ 6,600	6,600
Accumulated amortization		(6,600)	(6,513)
Net carrying amount		$ 0	$ 87
Other Intangible Assets [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life		1 year
Other Intangible Assets [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life		5 years

[1] Technology licenses relate to end-license agreements for intellectual property that is used by the Company in research and development activities and also has alternative future uses. Amortization expense related to technology licenses is reported as “Product development and engineering” in the condensed consolidated statements of operations.