Accounts payable and accrued liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 28, 2012	Dec. 30, 2011
Accounts Payable and Accrued Liabilities [Line Items]
Accounts payable	$ 7,010	$ 4,215
Accrued liabilities	3,376	2,523
Total accounts payable and other accrued liabilities	$ 10,386	$ 6,738