Segment Information - Revenue by Product Line (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 26, 2015	Jul. 27, 2014	Jul. 26, 2015	Jul. 27, 2014
Revenue from External Customer [Line Items]
Net sales	$ 125,712	$ 145,742	$ 255,800	$ 278,601
Signal Integrity [Member]
Revenue from External Customer [Line Items]
Net sales	59,024	60,232	113,333	111,511
Protection [Member]
Revenue from External Customer [Line Items]
Net sales	34,986	48,905	72,113	97,577
Wireless, Sensing and Timing [Member]
Revenue from External Customer [Line Items]
Net sales	15,533	19,793	38,331	38,141
Power and High Reliability [Member]
Revenue from External Customer [Line Items]
Net sales	16,105	16,521	30,118	29,966
Systems Innovation [Member]
Revenue from External Customer [Line Items]
Net sales	$ 64	$ 291	$ 1,905	$ 1,406
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	47.00%	41.00%	44.00%	40.00%
Net sales [Member] | Protection [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	28.00%	33.00%	28.00%	34.00%
Net sales [Member] | Wireless, Sensing and Timing [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	12.00%	14.00%	15.00%	14.00%
Net sales [Member] | Power and High Reliability [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	13.00%	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%	1.00%	1.00%