Segment Information - Revenue by Product Line (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 25, 2015	Oct. 26, 2014	Oct. 25, 2015	Oct. 26, 2014
Revenue from External Customer [Line Items]
Net sales	$ 115,810	$ 148,890	$ 371,610	$ 427,491
Signal Integrity [Member]
Revenue from External Customer [Line Items]
Net sales	52,449	56,345	165,780	167,856
Protection [Member]
Revenue from External Customer [Line Items]
Net sales	33,225	52,858	105,339	150,435
Wireless, Sensing and Timing [Member]
Revenue from External Customer [Line Items]
Net sales	16,567	22,683	54,898	60,824
Power and High Reliability [Member]
Revenue from External Customer [Line Items]
Net sales	13,554	16,549	43,673	46,515
Systems Innovation [Member]
Revenue from External Customer [Line Items]
Net sales	$ 15	$ 455	$ 1,920	$ 1,861
Net sales [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%	100.00%
Net sales [Member] | Signal Integrity [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	45.00%	38.00%	45.00%	39.00%
Net sales [Member] | Protection [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	29.00%	35.00%	28.00%	36.00%
Net sales [Member] | Wireless, Sensing and Timing [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	14.00%	15.00%	15.00%	14.00%
Net sales [Member] | Power and High Reliability [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	12.00%	11.00%	12.00%	11.00%
Net sales [Member] | Systems Innovation [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	0.00%	1.00%	0.00%	0.00%