Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019
Income Statement [Abstract]
Operating revenues	$ 17,882	$ 13,621	$ 37,142	$ 25,784
Operating costs	15,429	11,679	31,429	22,504
Gross profit	2,453	1,942	5,713	3,280
Selling, general and administrative expenses	2,314	2,450	4,447	4,755
Operating profit (loss)	139	(508)	1,266	(1,475)
Other income (expense):
Other income, net	1	26	2	41
Interest expense, net	(36)	(4)	(41)	(6)
Income (loss) from operations before income taxes	104	(486)	1,227	(1,440)
Provision for federal and state income taxes	36	31	58	51
Net income (loss)	$ 68	$ (517)	$ 1,169	$ (1,491)
Basic and diluted income (loss) per common share	$ 0	$ (0.02)	$ 0.04	$ (0.05)
Basic and diluted weighted average shares used in computing income (loss) per share	27,413	27,408	27,413	27,420