Restructuring and Related Charges (Detail) - Restructuring accrual activity (USD $)	3 Months Ended
	Mar. 30, 2013	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2011
Accrual	$ 877,000	$ 522,000	$ 732,000	$ 606,000
Charges and adjustments to expense	260,000	9,000
Cash payments	(115,000)	(93,000)
Lease Obligations [Member]
Accrual	671,000	468,000	732,000	499,000
Charges and adjustments to expense
Cash payments	(61,000)	(31,000)
Severance and other termination costs [Member]
Accrual	206,000	54,000		57,000
Charges and adjustments to expense	260,000	49,000
Cash payments	(54,000)	(52,000)
Other Cost [Member]
Accrual				50,000
Charges and adjustments to expense		(40,000)
Cash payments		$ (10,000)