Significant Accounting Policies - Allowances Against Accounts Receivable (Details) - USD ($) $ in Thousands	Jan. 31, 2016	Jan. 25, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for doubtful accounts	$ (7,793)	$ (3,523)
Allowance for Doubtful Accounts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for doubtful accounts	(889)	(1,678)
Sales Rebates Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for doubtful accounts	(5,006)	0
Sales Returns Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for doubtful accounts	(517)	(379)
Other Allowances
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for doubtful accounts	$ (1,381)	$ (1,466)