Note 4 - Summary of Significant Accounting Policies - Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Intangible assets	$ 8,000	$ 24,130
Istaroxime Drug Candidate [Member]
Intangible assets	6,210	22,340
Rostafuroxin Drug Candidate [Member]
Intangible assets	$ 1,790	$ 1,790

Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name Accounting Standards Codification
-Section 55
-Paragraph 40
-SubTopic 30
-Topic 350
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482640/350-30-55-40

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 350
-SubTopic 10
-Name Accounting Standards Codification
-Section S45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480265/350-10-S45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 350
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482665/350-30-50-2

Name:	us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant