Note 8 - Commitments and Contingencies - Licensing, Service and Supply Agreements (Details) $ in Thousands	Dec. 31, 2019 USD ($)
Amgen Fremont, Inc. Formerly Abgenix [Member]
Commitments, paid from inception	$ 1,350
Future Commitments	5,750	[1]
Former Member of PSMA LLC [Member]
Commitments, paid from inception	504
Future Commitments	52,188	[1]
Selexis Commercial License Agreement [Member]
Commitments, paid from inception	124
Future Commitments	1,824	[1]
University of Zurich and Paul Scherrer Institute [Member]
Commitments, paid from inception	590
Future Commitments	925	[1]
University of Western Ontario [Member]
Commitments, paid from inception	41
Future Commitments	151	[1]
Johns Hopkins University Technology [Member]
Commitments, paid from inception	435
Future Commitments	$ 2,500	[1]

[1] Amounts based on known contractual obligations as specified in the respective license agreements, which are dependent on the achievement or occurrence of future milestones or events and exclude amounts for royalties which are dependent on future sales and are unknown.