Goodwill and Intangible Assets - Schedule of Indefinite-lived Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Jul. 28, 2013	Jan. 25, 2015	Jan. 26, 2014
Indefinite-lived Intangible Assets [Roll Forward]
In-process research and development impairment	$ 2,600
In-process research and development
Indefinite-lived Intangible Assets [Roll Forward]
Beginning balance, gross carrying amount, indefinite-lived intangible assets		4,000	31,700
In-process research and development through acquisitions		0	0
In-process research and development impairment		0	(2,600)
Transfers to core technologies		0	(25,100)
Ending balance, gross carrying amount, indefinite-lived intangible assets		$ 4,000	$ 4,000

Indefinite-lived Intangible Assets, Period Decrease due to Transfer to Finite-lived Intangible Assets

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- Definition

Amount of impairment loss resulting from write-down of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit to fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

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- Definition

Amount of increase in assets, excluding financial assets and goodwill, lacking physical substance with an indefinite life, resulting from a business combination.

+ References

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- Definition

Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

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