Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]	Treasury Stock [Member]
Beginning Balance at Jan. 03, 2015	$ 73,976	$ 498	$ 238,229	$ (1,671)	$ (152,009)	$ (11,071)
Beginning Balance, Shares at Jan. 03, 2015		47,707,270
Grants of restricted stock		$ 3	(3)
Vesting of restricted stock, Shares		69,161,000
Purchases of treasury stock	(44)					(44)
Purchases of treasury stock, Shares		(3,746)
Retirement of treasury stock			(1,078)			1,078
Stock-based compensation	1,774		1,774
Exercise of stock options	$ 2,192	$ 10	2,182
Exercise of stock options, Shares	1,033,750	1,033,750
Tax benefit on exercised stock options	$ 3,840		3,840
Comprehensive income, net of tax effect	1,671			1,671
Net income	23,552				23,552
Ending Balance at Jan. 02, 2016	106,961	$ 511	244,944		(128,457)	(10,037)
Ending Balance, Shares at Jan. 02, 2016		48,806,435
Grants of restricted stock		$ 3	(3)
Vesting of restricted stock, Shares		128,590,000
Forfeitures of restricted stock		$ (1)	1
Purchases of treasury stock	$ (2,847)					(2,847)
Purchases of treasury stock, Shares	(299,988)	(299,988)
Retirement of treasury stock			(125)			125
Stock-based compensation	$ 1,769		1,769
Exercise of stock options	$ 981	$ 6	975
Exercise of stock options, Shares	537,364	537,364
Common stock issued under ESPP	$ 36		36
Common stock issued under ESPP, Shares		3,748
Tax benefit on exercised stock options	1,872		1,872
Net income	23,747				23,747
Ending Balance (Previously Reported [Member]) at Dec. 31, 2016	132,519	$ 519	249,469		(104,710)	(12,759)
Ending Balance at Dec. 31, 2016	$ 132,852
Ending Balance, Shares at Dec. 31, 2016	51,887,000	49,176,149
Cumulative effect of change in accounting for unrecognized excess tax benefits	$ 264				264
Cumulative effect of change in accounting for forfeitures relating to equity awards, net of tax effect	69		178		(109)
Ending Balance	132,852	$ 519	249,647		(104,555)	(12,759)
Ending Balance, Shares		49,176,149
Grants of restricted stock		$ 3	(3)
Vesting of restricted stock	0	$ 0	0	$ 0	0	0
Vesting of restricted stock, Shares		179,679,000
Forfeitures of restricted stock		$ (1)	1
Purchases of treasury stock	$ (284)					(284)
Purchases of treasury stock, Shares	(23,826)	(23,826)
Retirement of treasury stock			(284)			284
Stock-based compensation	$ 1,948		1,948
Exercise of stock options	$ 941	$ 4	937
Exercise of stock options, Shares	470,622	470,622
Common stock issued under ESPP	$ 29		29
Common stock issued under ESPP, Shares		2,714
Net income	39,839				39,839
Ending Balance at Dec. 30, 2017	$ 175,325	$ 525	$ 252,275		$ (64,716)	$ (12,759)
Ending Balance, Shares at Dec. 30, 2017	52,486,000	49,805,338