Note 2 - Revenue - Summary of Revenues (Details) - USD ($) $ in Thousands		12 Months Ended
	Nov. 05, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues		$ 157,170	$ 17,812	$ 48,835
Torii Pharmaceutical Co. [Member]
Revenues	$ 22,000
Product [Member]
Revenues		136,350	3,301	17,533
Product [Member] | ORLADEYO [Member]
Revenues		121,865	133
Product [Member] | RAPIVAB [Member]
Revenues		7,231	483	13,864
Product [Member] | PERAMIVIR [Member]
Revenues		7,254	2,685	3,669
Royalty [Member]
Revenues		(100)	3,381	6,303
Milestone [Member]
Revenues		15,000
Collaborative and Other Research and Development [Member]
Revenues		5,920	11,130	24,999
Collaborative and Other Research and Development [Member] | US Department of Health and Human Services [Member]
Revenues		$ 5,920	9,231	4,898
Collaborative and Other Research and Development [Member] | Torii Pharmaceutical Co. [Member]
Revenues			$ 1,899	$ 20,101