Segment Information - Revenue by Product Line (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2016	Jul. 26, 2015	Jul. 31, 2016	Jul. 26, 2015
Revenue from External Customer [Line Items]
Net sales	$ 135,911	$ 125,712	$ 267,056	$ 255,800
Signal Integrity [Member]
Revenue from External Customer [Line Items]
Net sales	63,313	59,024	133,400	113,333
Protection [Member]
Revenue from External Customer [Line Items]
Net sales	36,476	34,986	68,046	72,113
Wireless and Sensing [Member]
Revenue from External Customer [Line Items]
Net sales	20,837	15,533	36,444	38,331
Power and High Reliability [Member]
Revenue from External Customer [Line Items]
Net sales	15,285	16,105	29,166	30,118
Systems Innovation [Member]
Revenue from External Customer [Line Items]
Net sales	$ 0	$ 64	$ 0	$ 1,905
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%	47.00%	50.00%	44.00%
Net sales [Member] | Protection [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	27.00%	28.00%	25.00%	28.00%
Net sales [Member] | Wireless and Sensing [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	15.00%	12.00%	14.00%	15.00%
Net sales [Member] | Power and High Reliability [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	11.00%	13.00%	11.00%	12.00%
Net sales [Member] | Systems Innovation [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	0.00%	0.00%	0.00%	1.00%