Note 1 - Organization and Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Jul. 28, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Retained Earnings (Accumulated Deficit)		$ (1,499,945)		$ (1,499,945)		$ (1,527,033)
Revenue from Contract with Customer, Excluding Assessed Tax		165,815	$ 94	189,691	$ 2,705
Cash, Cash Equivalents, and Short-Term Investments		229,200		229,200
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				$ 48,900