Concentration of Risk - Narrative (Details)	12 Months Ended
Jan. 31, 2016	Jan. 25, 2015	Jan. 26, 2014
Accounts receivable
Minimum concentration risk threshold	10.00%
Net sales revenue
Minimum concentration risk threshold	10.00%
Concentration risk, percentage	100.00%	100.00%	100.00%
Authorized distributors [Member] \| Net sales revenue
Concentration risk, geographic	For fiscal year 2016, our two largest distributors were based in Asia.
Concentration risk, percentage	58.00%
Supplier concentration risk [Member] \| Cost of silicon wafers [Member]
Concentration risk, geographic	The Company’s largest source of silicon wafers is an outside foundry located in China and a significant amount of the Company’s assembly and test operations are conducted by third-party contractors in China, Malaysia, Taiwan, Thailand, Korea and the Philippines.
Concentration risk, percentage	28.00%	37.00%	38.00%

10.00%

58.00%

The Company’s largest source of silicon wafers is an outside foundry located in China and a significant amount of the Company’s assembly and test operations are conducted by third-party contractors in China, Malaysia, Taiwan, Thailand, Korea and the Philippines.