Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Income Statement [Abstract]
Operating revenues	$ 15,729	$ 13,974	$ 52,871	$ 39,758
Operating costs	14,585	12,299	46,014	34,803
Gross profit	1,144	1,675	6,857	4,955
Selling, general and administrative expenses	2,174	2,371	6,621	7,125
Operating profit (loss)	(1,030)	(696)	236	(2,170)
Other income (expense):
Other income, net	4	7	6	48
Interest expense, net	(62)	(5)	(103)	(12)
Income (loss) from operations before income taxes	(1,088)	(694)	139	(2,134)
Provision for federal and state income taxes	22	22	80	73
Net income (loss)	$ (1,110)	$ (716)	$ 59	$ (2,207)
Basic and diluted income (loss) per common share	$ (0.04)	$ (0.03)	$ 0.00	$ (0.08)
Basic and diluted weighted average shares used in computing income (loss) per share (in thousands)	27,507	27,410	27,529	27,417