Note 7 - Stockholders' Equity - Stock Option Valuation Assumptions (Details) - Share-Based Payment Arrangement, Option [Member]	12 Months Ended
Dec. 31, 2022
Expected dividend yield	0.38%
Minimum [Member]
Risk-free interest rate	3.94%
Maximum [Member]
Risk-free interest rate	4.65%

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iii)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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