Note 2 - Revenue (Details Textual) - USD ($) $ in Millions		12 Months Ended
	Jul. 28, 2023	Dec. 31, 2024	Dec. 31, 2023
Briumvi Ublituximab [Member] | Product [Member]
Gross Net Accruals		$ 32.0	$ 9.2
Product Sales, Net Related to Performance Obligations		3.7
Milestone Payments		12.5
Briumvi Ublituximab [Member] | Royalty [Member]
Revenue from Contract with Customer, Including Assessed Tax		0.8
Commercialization Agreement With Neuraxpharm [Member]
License and Collaboration Agreements, One-time, Non-refundable Payment	$ 140.0		$ 140.0
Royalty Percentage on Net Product Sales	30.00%
Revenue from Contract with Customer, Including Assessed Tax		1.8
Consideration Receivable, Performance Obligation		1.5
Contract with Customer, Asset, after Allowance for Credit Loss		$ 23.5
Commercialization Agreement With Neuraxpharm [Member] | Maximum [Member]
Qualified Sales-based Milestone Revenue	$ 505.0