Credit Facility and Capital Leases - Additional Information (Detail) (USD $)	0 Months Ended		3 Months Ended	6 Months Ended	3 Months Ended		0 Months Ended
	Jun. 30, 2013	Jun. 29, 2012	Jun. 30, 2013	Jun. 29, 2013	Jun. 30, 2013 Minimum	Jun. 30, 2012 Maximum	Jul. 05, 2012 Line of Credit	Jun. 30, 2013 Before July 5, 2013	Jun. 18, 2013 Before July 5, 2013	Jun. 30, 2013 After July 5, 2013	Jun. 18, 2013 After July 5, 2013	Jun. 30, 2013 Letter Of Credit Sublimit
Line of Credit Facility [Line Items]
Credit agreement term							3 years
Line of credit facility maximum borrowing capacity								$ 25,000,000.0	$ 25,000,000.0	$ 30,000,000.0	$ 30,000,000	$ 2,000,000.0
Line of credit facility reduction in commitment			10,000,000.0
Outstanding balance of revolving credit facility	575,000	850,000	575,000
Interest rate			(0.50%)
LIBOR rate	2.00%		2.00%
Revolving credit facility, maturity date			Jul. 05, 2015
Commitment fee	0.30%		0.30%	0.45%
Interest rate for borrowings under credit facility	2.20%		2.20%
Terminated credit facility		$ 20,000,000.0
Underlying property and equipment expiration period					September 2019
Weighted-average imputed interest rates for the capital lease agreements					2.54%	3.75%