Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 26, 2020	Dec. 28, 2019	Dec. 26, 2020	Dec. 28, 2019
Operating revenues	$ 11,577	$ 16,688	$ 64,449	$ 56,446
Operating income (loss)			(383)	(1,401)
Depreciation and amortization			449	389
Tangible assets	29,699	27,947	29,699	27,947
Goodwill	720	720	720	720
Other intangible assets	19	19	19	19
Total assets	30,438	28,686	30,438	28,686
Capital expenditures			428	345
EPCM
Operating revenues			25,929	19,436
Operating income (loss)			(69)	(830)
Depreciation and amortization			275	189
Tangible assets	7,389	6,253	7,389	6,253
Goodwill	0	0	0	0
Other intangible assets	0	0	0	0
Total assets	7,389	6,253	7,389	6,253
Capital expenditures			145	202
Automation
Operating revenues			38,520	37,010
Operating income (loss)			4,524	4,595
Depreciation and amortization			57	109
Tangible assets	7,806	12,864	7,806	12,864
Goodwill	720	720	720	720
Other intangible assets	19	19	19	19
Total assets	8,545	13,603	8,545	13,603
Capital expenditures			15	43
Corporate
Operating revenues			0	0
Operating income (loss)			(4,838)	(5,166)
Depreciation and amortization			117	91
Tangible assets	14,504	8,830	14,504	8,830
Goodwill	0	0	0	0
Other intangible assets	0	0	0	0
Total assets	$ 14,504	$ 8,830	14,504	8,830
Capital expenditures			$ 268	$ 100