Note 10 - Stock-based Compensation Plan - Stock Option Activity (Details) (Parentheticals) - shares	Sep. 30, 2023	Dec. 31, 2022
Options exercisable (in shares)	173,032	167,886

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant