Note 16 - Warrant Liabilities - Warrant Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021		Sep. 30, 2022	Sep. 30, 2021		Jun. 30, 2022	Dec. 31, 2021	Jul. 02, 2021	Jun. 30, 2021		Feb. 18, 2021		Dec. 31, 2020
Warrant liabilities as of the closing date	$ 1,280	$ 3,686		$ 1,280	$ 3,686		$ 257	$ 2,039	$ 58	$ 6,597		$ 11,921		$ 1,505
Change in fair value of warrants	1,023	(2,853)		(759)	(9,682)
Investor Warrants Issued in Connection with 2021 Financing [Member]
Warrant liabilities as of the closing date	782	1,824		782	1,824		167	964		3,257	[1]	10,476
Change in fair value of warrants	615	(1,433)		(182)	(8,652)
Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Warrant liabilities as of the closing date	106	237	[1]	106	237	[1]	22	132		431	[1]	$ 1,445	[1]
Change in fair value of warrants	84	(194)		(26)	(1,208)
Investor Warrants Issued in Connection with 2020 Financing [Member]
Warrant liabilities as of the closing date	328	1,383		328	1,383		57	795		2,420				1,279
Change in fair value of warrants	271	(1,037)		(467)	104
Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Warrant liabilities as of the closing date	64	242		64	242		$ 11	$ 148		423				224
Change in fair value of warrants	$ 53	(181)		$ (84)	18
Placement Agent Warrants Issued in Connection with 2018 Financing [Member]
Warrant liabilities as of the closing date		0			0				$ 58	$ 66	[2]			$ 2	[2]
Change in fair value of warrants		$ (8)			$ 56

[1] Closing date of the 2021 Financing.

[2] The investor warrants issued in the 2018 Financing expired in July 2020. The placement agent warrants issued in the 2018 Financing were cashless exercised in July 2021.