Note 8 - Derivatives (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Agent Warrants In Connection With March 2020 Private Placement [Member]
Derivative Liability, Total	$ 293		$ 293		$ 3,355
Derivative, Gain (Loss) on Derivative, Net, Total	743	$ 3,308	3,062	$ 35,474
Agent Warrants Issued in Connection with May 2020 Offering [Member]
Derivative Liability, Total	576		576		4,479
Derivative, Gain (Loss) on Derivative, Net, Total	1,133	3,370	3,903	35,421
Agent Warrants In Connection With June 2020 Warrant [Member]
Derivative Liability, Total	1,240		1,240		$ 5,999
Derivative, Gain (Loss) on Derivative, Net, Total	$ 1,587	$ 3,541	$ 4,759	$ 36,486