Note 10 - Stockholders' Equity - Fair Value Measurement of Warrant Liability (Details) - USD ($)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Base value of warrants, 515,000 warrants at $5	$ 2,575,000
Fair value adjustment	901,250	$ (0)
Balance at August 12, 2020 reclassified to equity	$ 3,476,250	$ 2,575,000

Amount of expense (income) related to adjustment to fair value of warrant liability.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section 25
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=109262497&loc=d3e20148-110875

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