Note 2 - Summary of Significant Accounting Policies - Other Non-current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Patents	$ 34	$ 34
Security deposits	36	36
Tax credit receivable	54	54
Total	$ 124	$ 124

Carrying amount due after one year of the balance sheet date (or one operating cycle, if longer) from tax authorities as of the balance sheet date representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(17))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

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