Note 8 - Stock-based Compensation - Stock-based Compensation (Details) - Selling, General and Administrative Expenses [Member] - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Stock options and restricted stock units, net of forfeitures	$ 28	$ 20	$ 46	$ 40
After-tax effect of stock-based compensation	$ 28	$ 20	$ 46	$ 40

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration