Segment Information - Revenue by Product Line (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 27, 2019	Oct. 28, 2018	Jul. 29, 2018	Apr. 29, 2018	Jan. 28, 2018	Oct. 29, 2017	Jul. 30, 2017	Apr. 30, 2017	Jan. 27, 2019	Jan. 28, 2018	Jan. 29, 2017
Revenue from External Customer [Line Items]
Net sales	$ 160,006	$ 173,550	$ 163,211	$ 130,429	$ 140,614	$ 150,304	$ 153,127	$ 143,802	$ 627,196	$ 587,847	$ 544,272
Signal Integrity [Member]
Revenue from External Customer [Line Items]
Net sales									276,040	263,015	258,824
Protection
Revenue from External Customer [Line Items]
Net sales									182,068	176,482	149,865
Wireless and Sensing [Member]
Revenue from External Customer [Line Items]
Net sales									190,589	164,569	140,774
Systems Innovation [Member]
Revenue from External Customer [Line Items]
Net sales									0	0	205
Other: Warrant Shares
Revenue from External Customer [Line Items]
Net sales offset									$ (21,501)	$ (16,219)	$ (5,396)
Net sales revenue
Revenue from External Customer [Line Items]
Concentration risk, percentage									100.00%	100.00%	100.00%
Net sales revenue | Signal Integrity [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage									44.00%	45.00%	47.00%
Net sales revenue | Protection
Revenue from External Customer [Line Items]
Concentration risk, percentage									29.00%	30.00%	28.00%
Net sales revenue | Wireless and Sensing [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage									30.00%	28.00%	26.00%
Net sales revenue | Systems Innovation [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage									0.00%	0.00%	0.00%
Net sales revenue | Other: Warrant Shares
Revenue from External Customer [Line Items]
Allocated share-based compensation expense as a percentage of net revenue									(3.00%)	(3.00%)	(1.00%)