Segment Information Schedule of Accounts Receivable by Major Customers (Details)	Jan. 31, 2016	Jan. 25, 2015
Accounts Receivable by Major Customers
Accounts receivable from significant customers (in percent)	21.00%	30.00%
Customer B (AR)
Accounts Receivable by Major Customers
Accounts receivable from significant customers (in percent)	21.00%	20.00%
Customer C (AR)
Accounts Receivable by Major Customers
Accounts receivable from significant customers (in percent)	8.00%	10.00%