Concentration of Risk - Narrative (Details)	12 Months Ended
Jan. 26, 2020	Jan. 27, 2019	Jan. 28, 2018
Net sales
Concentration Risk [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%
Net sales \| Distributor concentration risk
Concentration Risk [Line Items]
Concentration risk, percentage	72.00%	68.00%	66.00%
China \| Cost of Silicon Wafers \| Supplier Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	24.00%	16.00%	20.00%
Israel \| Cost of Silicon Wafers \| Supplier Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	11.00%	11.00%	14.00%

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.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13531-108611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13537-108611

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

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Period Type:	duration