Note 12 - Segment Reporting - Segment Information (Details) - USD ($)		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Assets		$ 38,919,604	$ 48,325,000	$ 38,919,604	$ 48,325,000	$ 40,935,925
Assets		(38,919,604)	(48,325,000)	(38,919,604)	(48,325,000)	$ (40,935,925)
Revenue		4,034,408	3,718,884	7,400,268	9,755,244
Operating (loss) income		(1,082,924)	(1,132,254)	(2,701,711)	(1,024,093)
Pretax income (loss)		1,471,489	(1,133,380)	(34,061)	(1,005,547)
Intersegment Eliminations [Member]
Assets	[1]	(66,000)	(9,000)	(66,000)	(9,000)
Assets	[1]	66,000	9,000	66,000	9,000
Revenue	[1]	(19,000)	(94,000)	(114,000)	(258,000)
Operating (loss) income	[1]	(734,000)	(761,000)	(1,704,000)	(1,491,000)
Pretax income (loss)	[1]	(734,000)	(761,000)	(1,704,000)	(1,491,000)
CVD [Member] | Operating Segments [Member]
Assets		28,149,000	36,509,000	28,149,000	36,509,000
Assets		(28,149,000)	(36,509,000)	(28,149,000)	(36,509,000)
Revenue		1,804,000	2,280,000	3,811,000	6,377,000
Operating (loss) income		(1,220,000)	(299,000)	(1,753,000)	293,000
Pretax income (loss)		1,209,000	(312,000)	661,000	277,000
SDC [Member] | Operating Segments [Member]
Assets		6,765,000	6,445,000	6,765,000	6,445,000
Assets		(6,765,000)	(6,445,000)	(6,765,000)	(6,445,000)
Revenue		1,162,000	1,016,000	1,987,000	2,835,000
Operating (loss) income		368,000	65,000	363,000	667,000
Pretax income (loss)		368,000	65,000	363,000	675,000
Materials [Member] | Operating Segments [Member]
Assets		3,940,000	5,380,000	3,940,000	5,380,000
Assets		(3,940,000)	(5,380,000)	(3,940,000)	(5,380,000)
Revenue		1,087,000	517,000	1,716,000	801,000
Operating (loss) income		503,000	(137,000)	392,000	(493,000)
Pretax income (loss)		$ 628,000	$ (125,000)	$ 646,000	$ (467,000)

[1] All elimination entries represent intersegment revenues eliminated in consolidation for external financial reporting.