Note 16 - The Financing and Warrant Liabilities - Warrant Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Jul. 02, 2021	Feb. 18, 2021	[1]	Dec. 31, 2020
Proceeds allocated to warrant liabilities	$ 185	$ 2,039				$ 1,505
Change in fair value of warrants	(1,854)	(11,329)
Change in fair value of warrant liabilities	1,854	11,329
Investor Warrants Issued in Connection with 2021 Financing [Member]
Proceeds allocated to warrant liabilities	86	964		$ 10,476
Change in fair value of warrants	(878)	(9,512)
Change in fair value of warrant liabilities	878	9,512
Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Proceeds allocated to warrant liabilities	9	132		$ 1,445
Change in fair value of warrants	(123)	(1,313)
Change in fair value of warrant liabilities	123	1,313
Investor Warrants Issued in Connection with 2020 Financing [Member]
Proceeds allocated to warrant liabilities	76	795				1,279
Change in fair value of warrants	(719)	(484)
Change in fair value of warrant liabilities	719	484
Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Proceeds allocated to warrant liabilities	14	148				224
Change in fair value of warrants	(134)	(76)
Change in fair value of warrant liabilities	$ 134	76
Placement Agent Warrants Issued in Connection with 2018 Financing [Member]
Proceeds allocated to warrant liabilities		0	$ 58			$ 2
Change in fair value of warrants		56
Change in fair value of warrant liabilities		$ (56)

[1] Closing date of the 2021 Financing.