Note 10 - Income Taxes (Details Textual)	12 Months Ended
Dec. 31, 2022 USD ($)
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ 33,000
State and Local Jurisdiction [Member]
Open Tax Year	2018 2019 2020 2021 2022
Internal Revenue Service (IRS) [Member] \| Domestic Tax Authority [Member]
Operating Loss Carryforwards	$ 1,400,000
Open Tax Year	2019 2020 2021 2022
Internal Revenue Service (IRS) [Member] \| Domestic Tax Authority [Member] \| Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount	$ 1,700,000
The Danish Ministry of Taxation [Member] \| Foreign Tax Authority [Member]
Operating Loss Carryforwards	$ 700,000

Tax year that remains open to examination under enacted tax laws, in YYYY format.

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-Name Accounting Standards Codification
-Topic 740
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