Note 10 - Segment Reporting (Details Textual)		3 Months Ended		6 Months Ended
	May 26, 2023 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)
Number of Operating Segments				3
Revenue from Contract with Customer, Including Assessed Tax		$ 5,069,000	$ 5,809,000	$ 13,764,000	$ 10,461,000
Loss on disposition of Tantaline		162,000	0	162,000	0
Asset Impairment Charges		111,000	0	111,000	0
MesoScribe Technologies, Inc [Member]
Revenue from Contract with Customer, Including Assessed Tax		300,000		500,000
Asset Impairment Charges		100,000		100,000
Tantaline A/S of Nordborg [Member]
Loss on disposition of Tantaline	$ 200,000	200,000		200,000
Intersegment Eliminations [Member]
Revenue from Contract with Customer, Including Assessed Tax		(202,000)	(380,000)	(331,000)	(425,000)
Intersegment Eliminations [Member] | SDC [Member]
Revenue from Contract with Customer, Including Assessed Tax		138,000	$ 380,000	266,000	425,000
Intersegment Eliminations [Member] | CVD [Member]
Revenue from Contract with Customer, Including Assessed Tax		$ 65,000		$ 65,000	$ 0