Note 1 - Summary of Significant Accounting Policies - Fair Value of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Total carrying amount of long-term debt	$ 36,787	$ 22,315
Estimated fair value of long-term debt	36,403	21,668
Fair Value, Recurring [Member]
Assets, fair value	6,471	24,927
Money Market Funds [Member] \| Fair Value, Recurring [Member]
Assets, fair value	6,471	24,927
Fair Value, Inputs, Level 1 [Member] \| Fair Value, Recurring [Member]
Assets, fair value	6,471	24,927
Fair Value, Inputs, Level 1 [Member] \| Money Market Funds [Member] \| Fair Value, Recurring [Member]
Assets, fair value	$ 6,471	$ 24,927

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/exampleRef
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Reference 3: http://www.xbrl.org/2003/role/exampleRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant