CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss.	Retained Earnings	Total
Balances at Dec. 28, 2018	$ 110	$ 114,008		$ 30,171	$ 144,289
Balances (in shares) at Dec. 28, 2018	10,968
Increase (Decrease) in Stockholders' Equity
Shares of common stock issued in connection with employee stock purchase plan		749			749
Shares of common stock issued in connection with employee stock purchase plan (in shares)	28
Shares of common stock issued in connection with incentive stock plan		291			291
Shares of common stock issued in connection with incentive stock plan (in shares)	21
Shares used to pay taxes on stock grants	$ (1)	(2,515)			(2,516)
Shares used to pay taxes on stock grants (in shares)	(66)
Issuance of restricted stock award and units	$ 2	(2)
Issuance of restricted stock award and units (in shares)	175
Stock-based compensation expense		1,817			1,817
Net income (loss)				(417)	(417)
Net unrealized gain (loss) on derivative contracts, net of tax			$ (219)		(219)
Balances at Mar. 29, 2019	$ 111	114,348	(219)	29,754	143,994
Balances (in shares) at Mar. 29, 2019	11,126
Balances at Dec. 28, 2018	$ 110	114,008		30,171	144,289
Balances (in shares) at Dec. 28, 2018	10,968
Increase (Decrease) in Stockholders' Equity
Net income (loss)					1,223
Net unrealized gain (loss) on derivative contracts, net of tax					(438)
Balances at Jun. 28, 2019	$ 112	116,457	(438)	31,394	147,525
Balances (in shares) at Jun. 28, 2019	11,194
Balances at Mar. 29, 2019	$ 111	114,348	(219)	29,754	143,994
Balances (in shares) at Mar. 29, 2019	11,126
Increase (Decrease) in Stockholders' Equity
Shares of common stock issued in connection with incentive stock plan	$ 1	231			232
Shares of common stock issued in connection with incentive stock plan (in shares)	77
Unregistered sales of equity securities and use of proceeds		(346)			(346)
Unregistered sales of equity securities and use of proceeds (in shares)	(9)
Stock-based compensation expense		2,224			2,224
Net income (loss)				1,640	1,640
Net unrealized gain (loss) on derivative contracts, net of tax			(219)		(219)
Balances at Jun. 28, 2019	$ 112	116,457	(438)	31,394	147,525
Balances (in shares) at Jun. 28, 2019	11,194
Balances at Dec. 27, 2019	$ 115	132,547	(396)	35,012	$ 167,278
Balances (in shares) at Dec. 27, 2019	11,497				11,497
Increase (Decrease) in Stockholders' Equity
Shares of common stock issued in connection with employee stock purchase plan	$ 0	1,073			$ 1,073
Shares of common stock issued in connection with employee stock purchase plan (in shares)	40
Shares of common stock issued in connection with incentive stock plan	$ 0	260			260
Shares of common stock issued in connection with incentive stock plan (in shares)	19
Shares used to pay taxes on stock grants	$ (1)	(2,866)			(2,867)
Shares used to pay taxes on stock grants (in shares)	(92)
Issuance of restricted stock award and units	$ 2	(1)			1
Issuance of restricted stock award and units (in shares)	176
Stock-based compensation expense		4,595			4,595
Net income (loss)				(8,154)	(8,154)
Net unrealized gain (loss) on derivative contracts, net of tax			(449)		(449)
Balances at Apr. 03, 2020	$ 116	135,608	(845)	26,858	161,737
Balances (in shares) at Apr. 03, 2020	11,640
Balances at Dec. 27, 2019	$ 115	132,547	(396)	35,012	$ 167,278
Balances (in shares) at Dec. 27, 2019	11,497				11,497
Increase (Decrease) in Stockholders' Equity
Net income (loss)					$ (13,139)
Net unrealized gain (loss) on derivative contracts, net of tax					(366)
Balances at Jul. 03, 2020	$ 120	140,165	(762)	21,873	$ 161,396
Balances (in shares) at Jul. 03, 2020	12,012				12,012
Balances at Apr. 03, 2020	$ 116	135,608	(845)	26,858	$ 161,737
Balances (in shares) at Apr. 03, 2020	11,640
Increase (Decrease) in Stockholders' Equity
Shares of common stock issued in connection with incentive stock plan	$ 1	330			331
Shares of common stock issued in connection with incentive stock plan (in shares)	63
Issuance of restricted stock award and units	$ 3	(3)
Issuance of restricted stock award and units (in shares)	309
Stock-based compensation expense		4,230			4,230
Net income (loss)				(4,985)	(4,985)
Net unrealized gain (loss) on derivative contracts, net of tax			83		83
Balances at Jul. 03, 2020	$ 120	$ 140,165	$ (762)	$ 21,873	$ 161,396
Balances (in shares) at Jul. 03, 2020	12,012				12,012