Note 1 - Organization and Summary of Significant Accounting Policies (Details Textual) $ in Thousands		12 Months Ended
	Jul. 28, 2023 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Retained Earnings (Accumulated Deficit)		$ (1,529,194)	$ (1,552,577)
Revenue from Contract with Customer, Excluding Assessed Tax		329,004	233,662	$ 2,785
Cash, Cash Equivalents, and Short-Term Investments		311,000
Restricted Cash and Investments		$ 1,300	1,300
Number of Reportable Segments		1
Commercialization Agreement With Neuraxpharm [Member]
License and Collaboration Agreements, One-time, Non-refundable Payment	$ 140,000		$ 140,000
Briumvi Ublituximab [Member]
Revenue from Contract with Customer, Excluding Assessed Tax		$ 313,700
Proceeds From Sales Returns		$ 100