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 Jan. 02, 2010	$ 22,458	$ 543	$ 32,860	$ (10,945)	$ 0
Balance (in shares) at Jan. 02, 2010		54,310
Comprehensive income:
Net income	31,568	0	0	31,568	0
Unrealized gain (loss) on available-for-sale marketable debt securities	0
Total comprehensive income	31,568
Exercise of common stock options	1,014	10	1,004	0	0
Exercise of common stock options (in shares)		958
Tax effect from stock-based compensation	366	0	366	0	0
Stock-based compensation	3,962	4	3,958	0	0
Stock-based compensation (in shares)		353
Repurchases of common stock	(1,391)	(2)	(1,389)	0	0
Repurchases of common stock (in shares)		(166)
Balance at Jan. 01, 2011	57,977	555	36,799	20,623	0
Balance (in shares) at Jan. 01, 2011		55,455
Comprehensive income:
Net income	60,478	0	0	60,478	0
Unrealized gain (loss) on available-for-sale marketable debt securities	25	0	0	0	25
Total comprehensive income	60,503
Exercise of common stock options	4,356	7	4,349	0	0
Exercise of common stock options (in shares)		725
Tax effect from stock-based compensation	1,865	0	1,865	0	0
Stock-based compensation	4,971	2	4,969	0	0
Stock-based compensation (in shares)		204
Repurchases of common stock	(371)	0	(371)	0	0
Repurchases of common stock (in shares)		(30)
Other	90	0	90	0	0
Other (shares)		43
Balance at Dec. 31, 2011	129,391	564	47,701	81,101	25
Balance (in shares) at Dec. 31, 2011	56,397	56,397
Comprehensive income:
Net income	78,094	0	0	78,094	0
Unrealized gain (loss) on available-for-sale marketable debt securities	(5)	0	0	0	(5)
Total comprehensive income	78,089
Exercise of common stock options	5,138	7	5,131	0	0
Exercise of common stock options (in shares)		659
Tax effect from stock-based compensation	5,665	0	5,665	0	0
Stock-based compensation	10,306	1	10,305	0	0
Stock-based compensation (in shares)		170
Repurchases of common stock	(34,892)	(13)	(34,879)	0	0
Repurchases of common stock (in shares)		(1,323)
Balance at Dec. 29, 2012	$ 193,697	$ 559	$ 33,923	$ 159,195	$ 20
Balance (in shares) at Dec. 29, 2012	55,903	55,903