Note 3 - Business Combination (Details Textual) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Jan. 09, 2023	Dec. 31, 2024	Dec. 31, 2023	Jun. 30, 2023
Goodwill			$ 0
Goodwill, Impairment Loss		$ 0	$ 60,934
Old Catheter [Member]
Business Combination, Consideration Transferred	$ 72,544
Goodwill	56,000			$ 60,934
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Royalties Payable	7,600			14,182
Goodwill, Impairment Loss	60,900
Business Combination, Acquisition Related Costs	1,700
Old Catheter [Member] | Developed Technology Rights [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	35,100			27,014
Old Catheter [Member] | Trademarks [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	1,700			1,285
Old Catheter [Member] | Customer Relationships [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 220			$ 62
Old Catheter [Member] | Series X Preferred Stock [Member]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares (in shares)	14,649.592
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable	$ 69,140
Business Acquisition, Share Price (in dollars per share)	$ 60.9
Old Catheter [Member] | Options to Purchase Common Stock [Member]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares (in shares)	75,367
Business Combination, Consideration Transferred	$ 3,400
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable	3,404
Old Catheter [Member] | Conversion of Convertible Promissory Notes into Series X Preferred Stock [Member]
Debt Conversion, Original Debt, Amount	$ 25,200