Note 2 - Basis of Presentation, Principles of Consolidation and Significant Accounting Policies - Schedule of Fair Value Measurements, Recurring and Nonrecurring (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Warrant Liability Long Term [Member]
Balance	$ 8,192	$ 5,818
Exercise of warrants	(52)	(4)
Issuances of warrants		4,724
Change in fair value - net	(6,728)	(2,346)
Balance	1,412	8,192
Warrant Liability [Member] \| Fair Value, Recurring [Member]
Fair value of warrant liability	1,412	8,192
Warrant Liability [Member] \| Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Fair value of warrant liability	0	0
Warrant Liability [Member] \| Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair value of warrant liability	0	0
Warrant Liability [Member] \| Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair value of warrant liability	$ 1,412	$ 8,192

Amount of gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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- Definition

Amount of issuances of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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Amount of settlements of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

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- Definition

Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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- Definition

Fair value of financial and nonfinancial obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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