Segment Information - Net Sales Activity by Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 29, 2017	Oct. 30, 2016	Jul. 31, 2016	May 01, 2016	Jan. 31, 2016	Oct. 25, 2015	Jul. 26, 2015	Apr. 26, 2015	Jan. 29, 2017	Jan. 31, 2016	Jan. 25, 2015
Revenue from External Customer [Line Items]
Net sales	$ 140,031	$ 137,185	$ 135,911	$ 131,145	$ 118,609	$ 115,810	$ 125,712	$ 130,088	$ 544,272	$ 490,219	$ 557,885
Semiconductor Products Group [Member]
Revenue from External Customer [Line Items]
Net sales									544,067	485,570	555,399
All Other Segments [Member]
Revenue from External Customer [Line Items]
Net sales									$ 205	$ 4,649	$ 2,486