Note 11 - Segment Reporting - Segment Information (Details) - USD ($)		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Assets		$ 60,640,848	$ 48,392,000	$ 58,978,250
Revenue		9,153,833	9,650,617
Operating income/(loss)		910,568	1,717,228
Pretax income/(loss)		806,174	1,708,166
Intersegment Eliminations [Member]
Assets		(7,000)
Revenue		(183,000)	(963,000)
Operating income/(loss)		(645,000)	(640,000)
Pretax income/(loss)		(645,000)	(640,000)
CVD [Member] | Operating Segments [Member]
Assets		45,333,000	43,969,000
Revenue		6,705,000	8,582,000
Operating income/(loss)		1,338,000	2,085,000
Pretax income/(loss)		1,333,000	2,076,000
SDC [Member] | Operating Segments [Member]
Assets		6,463,000	4,423,000
Revenue		2,260,000	2,032,000
Operating income/(loss)		731,000	617,000
Pretax income/(loss)		731,000	617,000
Materials [Member] | Operating Segments [Member]
Assets		8,852,000
Revenue	[1]	372,000
Operating income/(loss)	[1]	(513,000)	(345,000)
Pretax income/(loss)	[1]	$ (613,000)	$ (345,000)

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