Goodwill and Intangible Assets - Changes in Carrying Amounts of Goodwill (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Oct. 26, 2014
Goodwill [Roll Forward]
Balance as of January 26, 2014	$ 276,898
Transfers	0
Balance at October 26, 2014	276,898
Signal Integrity [Member]
Goodwill [Roll Forward]
Balance as of January 26, 2014	0
Transfers	261,891
Balance at October 26, 2014	261,891
Signal Integrity and Timing [Member]
Goodwill [Roll Forward]
Balance as of January 26, 2014	261,891
Transfers	(261,891)
Balance at October 26, 2014	0
Wireless and Sensing [Member]
Goodwill [Roll Forward]
Balance as of January 26, 2014	15,007
Transfers	(15,007)
Balance at October 26, 2014	0
Wireless, Sensing and Timing [Member]
Goodwill [Roll Forward]
Balance as of January 26, 2014	0
Transfers	15,007
Balance at October 26, 2014	$ 15,007