Note 2 - Going Concern (Details Textual) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Net Income (Loss) Attributable to Parent, Total	$ (11,858)	$ (10,785)	$ (16,505)	$ (11,540)	$ (22,643)	$ (28,045)
Net Cash Provided by (Used in) Operating Activities, Total					(34,992)	$ (9,759)
Retained Earnings (Accumulated Deficit), Total	$ (170,917)				$ (170,917)		$ (148,274)