Note 2 - Summary of Significant Accounting Policies - Calculation of Weighted Average Shares Used to Calculate Basic and Diluted Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Basic net loss per common share:
Net loss attributable to common shares - basic	$ (2,344)	$ (31,746)	$ (6,549)	$ (35,776)
Weighted average shares used in calculating basic loss per share	20,294,652	8,831,517	18,281,788	5,803,010
Basic net loss per common share	$ (0.12)	$ (3.59)	$ (0.36)	$ (6.17)
Diluted net loss per common share:
Net loss	$ (2,344)	$ (31,746)	$ (6,549)	$ (35,776)
Change in fair value of warrants	0	(5,119)	0	(5,119)
Net loss attributable to common shares - diluted	$ (2,344)	$ (36,865)	$ (6,549)	$ (40,895)
Weighted-average shares outstanding	20,294,652	8,831,517	18,281,788	5,803,010
Effect of potentially dilutive securities	0	152,681	0	76,341
Weighted average shares used in calculating diluted loss per share	20,294,652	8,984,198	18,281,788	5,879,351
Diluted net loss per common share	$ (0.12)	$ (4.10)	$ (0.36)	$ (6.96)