Note 9 - Income Taxes (Details Textual) - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Operating Loss Carryforwards, Total	$ 28,900,000		$ 28,900,000
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ 4,100,000	$ 600,000	$ 4,200,000	$ 700,000

Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32559-109319

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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