v3.23.1

Note 2 - Investments and Fair Value Measurement - Fair Value of Financial Assets and Liabilities by Level Within Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Assets, fair value	$ 11,637	$ 7,495
Liabilities, fair value	1,787	7,098
Warrant Liability [Member]
Liabilities, fair value	1,787
Fair Value, Inputs, Level 1 [Member]
Assets, fair value	146	321
Liabilities, fair value	0	0
Fair Value, Inputs, Level 1 [Member] | Warrant Liability [Member]
Liabilities, fair value	0
Fair Value, Inputs, Level 2 [Member]
Assets, fair value	11,491	7,174
Liabilities, fair value	0	0
Fair Value, Inputs, Level 2 [Member] | Warrant Liability [Member]
Liabilities, fair value	0
Fair Value, Inputs, Level 3 [Member]
Assets, fair value	0	0
Liabilities, fair value	1,787	7,098
Fair Value, Inputs, Level 3 [Member] | Warrant Liability [Member]
Liabilities, fair value	1,787
Money Market Funds [Member]
Assets, fair value	146	321
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value	146	321
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value	0	0
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, fair value	0	0
US Government Agencies Debt Securities [Member]
Assets, fair value	5,677	2,444
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value	0	0
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value	5,677	2,444
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, fair value	0	0
Commercial Paper [Member]
Assets, fair value	5,814	4,730
Commercial Paper [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, fair value	0	0
Commercial Paper [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, fair value	5,814	4,730
Commercial Paper [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, fair value	$ 0	$ 0

X

- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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X

- Definition

Fair value of financial and nonfinancial obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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