Note 5 - Stockholders' Equity - Common Stock Reserved for Future Issuance (Details)	Dec. 31, 2022 shares
Common stock reserved for future issuance (in shares)	15,459,615
Share-Based Payment Arrangement, Option [Member]
Common stock reserved for future issuance (in shares)	2,058,800
Stock options authorized for future grants (in shares)	16,700
Warrants [Member]
Common stock reserved for future issuance (in shares)	13,384,115

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant