Consolidated Statement of Shareholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 29, 2012	$ 193,697	$ 559	$ 33,923	$ 159,195	$ 20
Balance (in shares) at Dec. 29, 2012	55,903	55,903
Net income	23,471	0	0	23,471	0
Other comprehensive loss:
Unrealized loss on available-for-sale marketable debt securities, net of tax	(7)	0	0	0	(7)
Exercise of common stock options	2,282	2	2,280	0	0
Exercise of common stock options (in shares)		219
Tax effect from stock-based compensation	638	0	638	0	0
Stock-based compensation	432	0	432	0	0
Stock-based compensation (in shares)		(7)
Repurchases of common stock	(10,144)	(5)	(10,139)	0	0
Repurchases of common stock (in shares)		(465)
Balance at Mar. 30, 2013	$ 210,369	$ 556	$ 27,134	$ 182,666	$ 13
Balance (in shares) at Mar. 30, 2013	55,650	55,650