Goodwill and Intangible Assets - Changes in Carrying Amounts of Goodwill (Details) $ in Thousands	6 Months Ended
	Jul. 26, 2015 USD ($)
Goodwill [Roll Forward]
Balance at January 25, 2015	$ 280,319
Additions	49,384
Balance at July 26, 2015	329,703
Signal Integrity [Member]
Goodwill [Roll Forward]
Balance at January 25, 2015	261,891
Additions	0
Balance at July 26, 2015	261,891
Power and High Reliability [Member]
Goodwill [Roll Forward]
Balance at January 25, 2015	0
Additions	49,384
Balance at July 26, 2015	49,384
Wireless, Sensing and Timing [Member]
Goodwill [Roll Forward]
Balance at January 25, 2015	18,428
Additions	0
Balance at July 26, 2015	$ 18,428