Goodwill and Intangible Assets - Goodwill Balances (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended												12 Months Ended
	Jan. 26, 2014		Oct. 27, 2013	Jul. 28, 2013	Apr. 28, 2013		Jan. 27, 2013		Oct. 28, 2012	Jul. 29, 2012	Apr. 29, 2012		Jan. 26, 2014		Jan. 27, 2013		Jan. 29, 2012
Goodwill [Roll Forward]
Beginning balance					$ 393,584						$ 129,651		$ 393,584		$ 129,651
Acquisitions															263,933
Impairments	(116,686)		0	0	0		0		0	0	0		(116,686)		0		0
Transfers													0
Ending balance	276,898						393,584						276,898		393,584		129,651
Signal Integrity and Timing
Goodwill [Roll Forward]
Beginning balance					0						0		0		0
Acquisitions															0
Impairments													0
Transfers													261,891
Ending balance	261,891						0						261,891		0
Gennum
Goodwill [Roll Forward]
Beginning balance					261,891	[1]					0	[1]	261,891	[1]	0	[1]
Acquisitions															261,891	[1]
Impairments													0	[1]
Transfers													(261,891)	[1]
Ending balance	0	[1]					261,891	[1]					0	[1]	261,891	[1]
Advanced Communications
Goodwill [Roll Forward]
Beginning balance					116,686	[1]					116,686	[1]	116,686	[1]	116,686	[1]
Acquisitions															0	[1]
Impairments													(116,686)	[1]
Transfers													0	[1]
Ending balance	0	[1]					116,686	[1]					0	[1]	116,686	[1]
Wireless and Sensing
Goodwill [Roll Forward]
Beginning balance					15,007						12,965		15,007		12,965
Acquisitions															2,042
Impairments													0
Transfers													0
Ending balance	$ 15,007						$ 15,007						$ 15,007		$ 15,007

[1] In the fourth quarter of fiscal year 2014, the Gennum and Advanced Communications reporting units were integrated to form the new reporting unit Signal Integrity and Timing.