Note 7 - Share-based Compensation - Compensation Cost (Details) - Selling, General and Administrative Expenses [Member] - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Share-based compensation	$ 692	$ 501
Common Stock [Member]
Share-based compensation	100	100
Employee and Nonemployee Stock Option [Member]
Share-based compensation	53	53
Restricted Stock Units (RSUs) [Member]
Share-based compensation	$ 539	$ 348

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