Note 11 - Segment Reporting - Segment Information (Details) - USD ($)		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Assets		$ 48,794,437	$ 50,628,000	$ 46,723,052
Revenue		6,036,360	3,468,675
Operating income/(loss)		108,161	(2,565,102)
Pretax income/(loss)		127,834	(2,632,947)
Intersegment Eliminations [Member]
Assets	[1]	(9,000)	(9,000)
Revenue	[1]	(164,000)	(66,000)
Operating income/(loss)	[1]	(730,000)	(1,001,000)
Pretax income/(loss)	[1]	(730,000)	(1,002,000)
CVD [Member] | Operating Segments [Member]
Assets		36,699,000	38,604,000
Revenue		4,097,000	2,019,000
Operating income/(loss)		592,000	(1,540,000)
Pretax income/(loss)		589,000	(1,511,000)
SDC [Member] | Operating Segments [Member]
Assets		6,451,000	5,182,000
Revenue		1,819,000	1,087,000
Operating income/(loss)		603,000	174,000
Pretax income/(loss)		610,000	176,000
Materials [Member] | Operating Segments [Member]
Assets		5,653,000	6,851,000
Revenue		284,000	429,000
Operating income/(loss)		(357,000)	(198,000)
Pretax income/(loss)		$ (341,000)	$ (296,000)

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