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Note 3 - Investments and Agreements (Details Textual) - USD ($)									12 Months Ended
	Feb. 02, 2026	Feb. 18, 2025	Jan. 08, 2025	May 24, 2024	Apr. 11, 2024	Mar. 04, 2024	Jan. 17, 2024	Jan. 08, 2024	Dec. 31, 2025	Dec. 31, 2024	Aug. 13, 2024	Mar. 31, 2024	Dec. 14, 2023	Nov. 17, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock issued during period, shares		3,379,377
Common stock, par value									$ 0.001	$ 0.001
Stock purchase price per share		$ 3.02
Proceeds from issuance of common stock		$ 10,200,000
Maximum amount of securities offer and sell													$ 200,000,000
Other income from a related party									$ 1,400,000	$ 0
January 2024 Pre-funded Warrants [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Warrants to purchase shares of common stock							3,008,694
Warrant exercise price per share							$ 3.69
Percentage of ownership considered for warrant exercise							4.99%
Maximum increase or decrease in ownership percentage							19.99%
Underwriting Agreement [Member] \| May 2024 Pre-funded Warrants [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Warrants to purchase shares of common stock	6,598,046
2024 At-the-Market (ATM) Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Agent commission fee as a percentage of gross sales price											3.00%
Stock issued during period, shares		3,379,377
Stock purchase price per share		$ 3.02
Proceeds from issuance of common stock		$ 10,200,000
2024 At-the-Market (ATM) Agreement [Member] \| Common Stock [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum amount of securities offer and sell											$ 250,000,000
March 2024 Private Placement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock issued during period, shares						9,200,998
Stock purchase price per share						$ 9.5
Proceeds from issuance of common stock						$ 87,400,000
Placement agents cash fee, percentage						5.85%
Lantheus Investment Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock issued during period, shares								5,634,235
Investment agreement, contingent amount of gross proceeds raised								$ 50,000,000
Percent of outstanding shares								19.99%
Asset purchase price in cash								$ 8,000,000
Lantheus Investment Agreement \| Option Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percent of outstanding shares												19.90%
One-time payment received for rights granted								28,000,000
Repayment provisions								$ 0
Other income from a related party			$ 1,400,000
Public Offering [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock issued during period, shares							13,207,521
Sale of stock, price per share							$ 3.7
Shares and warrants, price difference per share							$ 0.01
Gross proceeds from public offering							$ 69,000,000
Over-Allotment Option [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock issued during period, shares							2,432,432
Oppenheimer & Co [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock issued during period, shares					3,535,246
Stock purchase price per share					$ 14
Proceeds from issuance of common stock					$ 49,500,000
Maximum amount of securities offer and sale														$ 50,000,000
BofA Securities, Inc [Member] \| Underwriting Agreement [Member] \| May 2024 Pre-funded Warrants [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Warrants to purchase shares of common stock				146,425
Warrant exercise price per share				$ 15.09
Percentage of ownership considered for warrant exercise				4.99%
Percentage of ownership considered for warrant exercise				9.99%
Maximum increase or decrease in ownership percentage				19.99%
BofA Securities, Inc [Member] \| Registered Offering [Member] \| Underwriting Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock issued during period, shares				5,151,588
Sale of stock, price per share				$ 15.1
Shares and warrants, price difference per share				$ 0.01
Gross proceeds from public offering				$ 80,000,000
Piper Sandler & Co. and UBS Securities LLC [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Proceeds from issuance of common stock	$ 175,000,000
Piper Sandler & Co. and UBS Securities LLC [Member] \| Subsequent Event [Member] \| Underwriting Agreement [Member] \| 2026 Pre-funded Warrants [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Warrants to purchase shares of common stock	6,598,046
Warrant exercise price per share	$ 3.789
Percentage of ownership considered for warrant exercise	4.99%
Percentage of ownership considered for warrant exercise	9.99%
Maximum increase or decrease in ownership percentage	19.99%
Piper Sandler & Co. and UBS Securities LLC [Member] \| Subsequent Event [Member] \| 2026 Offering [Member] \| Underwriting Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Stock issued during period, shares	39,576,088
Sale of stock, price per share	$ 3.79
Shares and warrants, price difference per share	$ 0.001
Gross proceeds from public offering	$ 175,000,000