Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Comprehensive Income [Member]
Beginning Balance Value at Jan. 02, 2010	$ 106,754	$ 21	$ 218,308	$ (112,948)	$ 1,373
Beginning Balance Shares at Jan. 02, 2010		21,506,791
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	55,948			55,948		55,948
Employee benefit plan adjustment	(51)				(51)	(51)
Foreign currency translation adjustments	750				750	750
Unrealized loss on investments, net of tax	0
Issuance of common stock under stock-based compensation plans, Value	6,623	1	6,622
Issuance of common stock under stock-based compensation plans, Shares		969,484
Common stock offering costs	(28)		(28)
Share-based compensation expense	2,950		2,950
Repurchases and retirement of common stock, Value	(2,097)	0	(2,097)
Repurchases and retirement of common stock, Shares		(161,492)
Ending Balance Value at Jan. 01, 2011	170,849	22	225,755	(57,000)	2,072
Ending Balance Shares at Jan. 01, 2011		22,314,783
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	28,685			28,685		28,685
Employee benefit plan adjustment	(39)				(39)	(39)
Foreign currency translation adjustments	(484)				(484)	(484)
Unrealized loss on investments, net of tax	0
Issuance of common stock under stock-based compensation plans, Value	10,765	1	10,764
Issuance of common stock under stock-based compensation plans, Shares		1,133,028
Share-based compensation expense	4,473		4,473
Repurchases and retirement of common stock, Value	(4,257)	0	(4,257)
Repurchases and retirement of common stock, Shares		(265,040)
Ending Balance Value at Dec. 31, 2011	209,992	23	236,735	(28,315)	1,549
Ending Balance Shares at Dec. 31, 2011	23,182,771	23,182,771
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	4,465			4,465		4,465
Employee benefit plan adjustment	(11)				(11)	(11)
Foreign currency translation adjustments	(264)				(264)	(264)
Unrealized loss on investments, net of tax	(2)				(2)	(2)
Issuance of common stock under stock-based compensation plans, Value	4,205	0	4,205
Issuance of common stock under stock-based compensation plans, Shares		655,424
Share-based compensation expense	5,890		5,890
Repurchases and retirement of common stock, Value	(8,504)	0	(8,504)
Repurchases and retirement of common stock, Shares	(587,766)	(587,766)
Ending Balance Value at Dec. 29, 2012	$ 215,771	$ 23	$ 238,326	$ (23,850)	$ 1,272
Ending Balance Shares at Dec. 29, 2012	23,250,429	23,250,429