Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
REVENUES	$ 6,882	$ 7,059	$ 13,418	$ 15,677
Type of Revenue [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Costs and expenses:
Manufacturing cost of sales	$ 4,151	$ 4,816	$ 8,552	$ 10,478
Engineering, selling and administrative	2,115	2,059	4,310	4,355
OPERATING INCOME	616	184	556	844
Other (expense) income:
Interest expense, net	(3)	(4)	(6)	(4)
Loss on equity investment in unconsolidated subsidiary	(676)	(100)	(752)	(139)
Other income (expense), net	70	232	242	(152)
Total other (expense) income, net	(609)	128	(516)	(295)
INCOME BEFORE INCOME TAXES	7	312	40	549
Income tax expense	25	57	31	111
NET (LOSS) INCOME	$ (18)	$ 255	$ 9	$ 438
Basic per share information:
Weighted average shares outstanding	5,272,204	5,211,773	5,272,204	5,132,414
Net (loss) income	$ 0.00	$ 0.05	$ 0.00	$ 0.09
Diluted per share information:
Weighted average shares outstanding	5,272,204	5,245,162	5,337,986	5,170,740
Net (loss) income	$ 0.00	$ 0.05	$ 0.00	$ 0.08