Segment Information Net Sales Activity by Segment (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Jan. 25, 2015	Oct. 26, 2014	Jul. 27, 2014	Apr. 27, 2014	Jan. 26, 2014	Oct. 27, 2013	Jul. 28, 2013	Apr. 28, 2013	Jan. 25, 2015	Jan. 26, 2014	Jan. 27, 2013
Revenue from External Customer [Line Items]
Net sales	$ 130,394	$ 148,890	$ 145,742	$ 132,859	$ 126,534	$ 141,026	$ 165,010	$ 162,407	$ 557,885	$ 594,977	$ 578,827
Semiconductor Products Group [Member]
Revenue from External Customer [Line Items]
Net sales									555,399	577,312	559,729
All Other Segments [Member]
Revenue from External Customer [Line Items]
Net sales									$ 2,486	$ 17,665	$ 19,098