Note 9 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Mar. 27, 2020
Deferred Tax Assets, Valuation Allowance, Total	$ 3,381,133	$ 2,497,414
Income Taxes Receivable	700,000		$ 1,500,000
Net Income (Loss) Attributable to Parent, Total	(6,074,952)	(6,327,658)
Deferred Tax Assets, Gross, Total	3,937,609	2,939,900
CVD Tantaline ApS [Member] | DENMARK
Net Income (Loss) Attributable to Parent, Total	336,000	(276,000)
Deferred Tax Assets, Gross, Total	$ 74,000	$ 61,000
CVD Tantaline ApS [Member] | DENMARK | Foreign Tax Authority [Member] | The Danish Ministry of Taxation [Member]
Effective Income Tax Rate Reconciliation, at Foreign Statutory Income Tax Rate, Percent	22.00%
Research [Member]
Tax Credit Carryforward, Amount	$ 1,719,598