Segment Information Revenue by Country (Details) - Net sales revenue	12 Months Ended
	Jan. 31, 2016	Jan. 25, 2015	Jan. 26, 2014
Geographic Information And Concentration Of Risk [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%
Geographic Concentration Risk [Member]
Geographic Information And Concentration Of Risk [Line Items]
Concentration risk, percentage	73.00%	70.00%	72.00%
China Including Hong Kong [Member] | Geographic Concentration Risk [Member]
Geographic Information And Concentration Of Risk [Line Items]
Concentration risk, percentage	47.00%	38.00%	34.00%
United States | Geographic Concentration Risk [Member]
Geographic Information And Concentration Of Risk [Line Items]
Concentration risk, percentage	12.00%	12.00%	16.00%
Japan | Geographic Concentration Risk [Member]
Geographic Information And Concentration Of Risk [Line Items]
Concentration risk, percentage	8.00%	11.00%	11.00%
South Korea | Geographic Concentration Risk [Member]
Geographic Information And Concentration Of Risk [Line Items]
Concentration risk, percentage	6.00%	9.00%	11.00%