Segment Information - Revenue by Product Line (Details) - USD ($)	3 Months Ended
Apr. 30, 2017	May 01, 2016
Revenue from External Customer [Line Items]
Net sales	$ 143,802,000	$ 131,145,000
Signal Integrity [Member]
Revenue from External Customer [Line Items]
Net sales	68,058,000	69,882,000
Protection [Member]
Revenue from External Customer [Line Items]
Net sales	42,249,000	31,570,000
Wireless and Sensing [Member]
Revenue from External Customer [Line Items]
Net sales	28,010,000	15,607,000
Power and High Reliability [Member]
Revenue from External Customer [Line Items]
Net sales	10,765,000	13,881,000
Systems Innovation [Member]
Revenue from External Customer [Line Items]
Net sales	0	205,000
Other: Warrant Shares [Member]
Revenue from External Customer [Line Items]
Net sales offset	$ (5,280,000)	$ 0
Net sales [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	100.00%	100.00%
Net sales [Member] \| Signal Integrity [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	49.00%	53.00%
Net sales [Member] \| Protection [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	29.00%	24.00%
Net sales [Member] \| Wireless and Sensing [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	19.00%	12.00%
Net sales [Member] \| Power and High Reliability [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	7.00%	11.00%
Net sales [Member] \| Systems Innovation [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	0.00%	0.00%
Net sales [Member] \| Other: Warrant Shares [Member]
Revenue from External Customer [Line Items]
Concentration risk, percentage	(4.00%)	0.00%

Allocated share-based compensation expense as a percentage of net revenue

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- Definition

Revenue Offset

+ References

No definition available.

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=64851502&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13531-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=64851502&loc=d3e6404-108592

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13537-108611

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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