Condensed Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Previously Reported [Member]	Common Stock [Member]	Common Stock [Member] Previously Reported [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] Previously Reported [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Other Comprehensive Loss [Member] Previously Reported [Member]	Retained Earnings/(Accumulated Deficit) [Member]	Retained Earnings/(Accumulated Deficit) [Member] Previously Reported [Member]	Treasury Stock [Member]	Treasury Stock [Member] Previously Reported [Member]
Beginning Balance at Dec. 30, 2017		$ 175,325		$ 525		$ 252,275				$ (64,716)		$ (12,759)
Beginning Balance, Shares at Dec. 30, 2017				49,805,338
Cumulative effect of change in accounting principle, net of tax effect (Accounting Standards Update 2014-09 [Member]) at Dec. 30, 2017	$ 1,883								$ 1,883
Beginning Balance at Dec. 30, 2017	177,208		$ 525		$ 252,275				(62,833)		$ (12,759)
Beginning Balance, Shares at Dec. 30, 2017			49,805,338
Vesting of restricted stock, Shares			151,174
Grants of restricted stock			$ 1		(1)
Purchases of treasury stock	(637)										(637)
Purchases of treasury stock, Shares			(32,439)
Retirement of treasury stock			$ (1)		(636)						637
Stock-based compensation	2,030				2,030
Exercise of stock options	1,928		$ 10		1,918
Exercise of stock options, Shares			964,780
Common stock issued under ESPP	18				18
Common stock issued under ESPP, Shares			1,106
Issuances under Equity Offering	152,653		$ 70		152,583
Issued under equity offering, Shares			7,000,000
Issuances under Employee Grant	513				513
Issued in employee grant, Shares			24,590
Net income	43,459								43,459
Other comprehensive income (loss)	(824)						$ (824)
Ending Balance at Sep. 29, 2018	376,348		$ 605		408,700		(824)		(19,374)		(12,759)
Ending Balance, Shares at Sep. 29, 2018			57,914,549
Beginning Balance at Jun. 30, 2018		$ 208,844		$ 533		$ 254,399		$ (384)		$ (32,945)		$ (12,759)
Beginning Balance, Shares at Jun. 30, 2018				50,705,766
Stock-based compensation	832				832
Exercise of stock options	367		$ 2		365
Exercise of stock options, Shares			183,808
Common stock issued under ESPP	8				8
Common stock issued under ESPP, Shares			385
Issuances under Equity Offering	152,653		$ 70		152,583
Issued under equity offering, Shares			7,000,000
Issuances under Employee Grant	513				513
Issued in employee grant, Shares			24,590
Net income	13,571								13,571
Other comprehensive income (loss)	(440)						(440)
Ending Balance at Sep. 29, 2018	376,348		$ 605		408,700		(824)		(19,374)		(12,759)
Ending Balance, Shares at Sep. 29, 2018			57,914,549
Beginning Balance at Dec. 29, 2018	385,544		$ 607		409,661		(3,065)		(8,900)		(12,759)
Beginning Balance, Shares at Dec. 29, 2018			58,081,540
Vesting of restricted stock, Shares			164,226
Grants of restricted stock			$ 5		(5)
Purchases of treasury stock	(6,055)										(6,055)
Purchases of treasury stock, Shares			(428,059)
Retirement of treasury stock					(505)						505
Stock-based compensation	3,246				3,246
Exercise of stock options	$ 1,262		$ 5		1,257
Exercise of stock options, Shares	532,931		532,931
Common stock issued under ESPP	$ 46				46
Common stock issued under ESPP, Shares			3,165
Net income	40,408								40,408
Other comprehensive income (loss)	1,181						1,181
Ending Balance at Sep. 28, 2019	425,632		$ 617		413,700		(1,884)		31,508		(18,309)
Ending Balance, Shares at Sep. 28, 2019			58,353,803
Beginning Balance at Jun. 29, 2019	414,375		$ 615		412,295		(2,178)		16,402		(12,759)
Beginning Balance, Shares at Jun. 29, 2019			58,535,669
Purchases of treasury stock	$ (5,550)										(5,550)
Purchases of treasury stock, Shares	(393,819,000)		(393,819)
Stock-based compensation	$ 970				970
Exercise of stock options	$ 422		$ 2		420
Exercise of stock options, Shares	210,931		210,931
Common stock issued under ESPP	$ 15				15
Common stock issued under ESPP, Shares			1,022
Net income	15,106								15,106
Other comprehensive income (loss)	294						294
Ending Balance at Sep. 28, 2019	$ 425,632		$ 617		$ 413,700		$ (1,884)		$ 31,508		$ (18,309)
Ending Balance, Shares at Sep. 28, 2019			58,353,803