Accounts receivable, net (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 28, 2012	Dec. 30, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for contract losses and doubtful accounts	$ (2,666)	$ (2,339)
Total accounts receivable, net	85,361	73,065
Billed accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	54,653	50,338
Unbilled accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	$ 33,374	$ 25,066