Concentration of Risk - Narrative (Details)	3 Months Ended		12 Months Ended
	Apr. 29, 2018	Apr. 30, 2017	Jan. 28, 2018
Concentration Risk [Line Items]
Description of geographic concentration risk related to distributors	For the third quarter of fiscal year 2018, our two largest distributors were based in Asia.
Accounts Receivable [Member]
Concentration Risk [Line Items]
Minimum concentration risk threshold	10.00%		10.00%
Net sales [Member]
Concentration Risk [Line Items]
Minimum concentration risk threshold	10.00%
Concentration risk, percentage	100.00%	100.00%
Net sales [Member] | Distributor concentration risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	69.00%	64.00%
China | Cost of Silicon Wafers [Member] | Supplier concentration risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	14.00%	21.00%