Note 16 - Warrant Liabilities - Fair Value of Warrants (Details) $ in Thousands		Sep. 30, 2022 USD ($) yr	Jun. 30, 2022 USD ($) yr	Dec. 31, 2021 USD ($) yr	Sep. 30, 2021 USD ($) yr		Jul. 02, 2021 USD ($)	Jun. 30, 2021 USD ($) yr		Feb. 18, 2021 USD ($)		Dec. 31, 2020 USD ($) yr
Warrant liabilities as of the closing date		$ 1,280	$ 257	$ 2,039	$ 3,686		$ 58	$ 6,597		$ 11,921		$ 1,505
Investor Warrants Issued in Connection with 2021 Financing [Member]
Warrant liabilities as of the closing date		782	167	964	1,824			3,257	[1]	10,476
Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Warrant liabilities as of the closing date		106	22	132	237	[1]		431	[1]	$ 1,445	[1]
Investor Warrants Issued in Connection with 2020 Financing [Member]
Warrant liabilities as of the closing date		328	57	795	1,383			2,420				1,279
Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Warrant liabilities as of the closing date		$ 64	$ 11	$ 148	242			423				224
Investor Warrants Issued in Connection with 2018 Financing [Member]
Warrant liabilities as of the closing date	[2]						58
Placement Agent Warrants Issued in Connection with 2018 Financing [Member]
Warrant liabilities as of the closing date					$ 0		$ 58	$ 66	[2]			$ 2	[2]
Measurement Input, Share Price [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		0.92	0.34	1.00	1.26			2.00	[1]	4.48
Measurement Input, Share Price [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		0.92	0.34	1.00	1.26	[1]		2.00	[1]	4.48	[1]
Measurement Input, Share Price [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		0.92	0.34	1.00	1.26			2.00				1.35
Measurement Input, Share Price [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		0.92	0.34	1.00	1.26			2.00				1.35
Measurement Input, Share Price [Member] | Investor Warrants Issued in Connection with 2018 Financing [Member]
Fair value of the warrants	[2]						1.94
Measurement Input, Share Price [Member] | Placement Agent Warrants Issued in Connection with 2018 Financing [Member]
Fair value of the warrants	[2]							2.00				1.35
Measurement Input, Expected Term [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		1.88	2.13	2.63	2.88			3.14	[1]	3.50
Measurement Input, Expected Term [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		1.88	2.13	2.63	2.88	[1]		3.14	[1]	3.50	[1]
Measurement Input, Expected Term [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		1.20	1.45	1.95	2.20			2.45				2.95
Measurement Input, Expected Term [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		1.20	1.45	1.95	2.20			2.45				2.95
Measurement Input, Expected Term [Member] | Investor Warrants Issued in Connection with 2018 Financing [Member]
Fair value of the warrants	[2]						0.04
Measurement Input, Expected Term [Member] | Placement Agent Warrants Issued in Connection with 2018 Financing [Member]
Fair value of the warrants	[2]							0.05				0.05
Measurement Input, Risk Free Interest Rate [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		0.0416	0.0297	0.0087	0.0050			0.0048	[1]	0.0026
Measurement Input, Risk Free Interest Rate [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		0.0416	0.0297	0.0087	0.0050	[1]		0.0048	[1]	0.0026	[1]
Measurement Input, Risk Free Interest Rate [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		0.0390	0.0279	0.0072	0.0034			0.0034				0.0017
Measurement Input, Risk Free Interest Rate [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		0.0390	0.0279	0.0072	0.0034			0.0034				0.0017
Measurement Input, Risk Free Interest Rate [Member] | Investor Warrants Issued in Connection with 2018 Financing [Member]
Fair value of the warrants	[2]						0.0005
Measurement Input, Risk Free Interest Rate [Member] | Placement Agent Warrants Issued in Connection with 2018 Financing [Member]
Fair value of the warrants	[2]							0.0004				0.0008
Measurement Input, Price Volatility [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		1.27	1.24	1.15	1.15			1.14	[1]	1.68
Measurement Input, Price Volatility [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		1.27	1.24	1.15	1.15	[1]		1.14	[1]	1.68	[1]
Measurement Input, Price Volatility [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		1.03	1.07	1.28	1.22			1.20				1.02
Measurement Input, Price Volatility [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		1.03	1.07	1.28	1.22			1.20				1.02
Measurement Input, Price Volatility [Member] | Investor Warrants Issued in Connection with 2018 Financing [Member]
Fair value of the warrants	[2]						0.75
Measurement Input, Price Volatility [Member] | Placement Agent Warrants Issued in Connection with 2018 Financing [Member]
Fair value of the warrants	[2]							0.74				0.59
Measurement Input, Exercise Price [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		3.59	3.59	3.59	3.59			3.59	[1]	3.59
Measurement Input, Exercise Price [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		4.4875	4.4875	4.4875	4.4875	[1]		4.4875	[1]	4.4875	[1]
Measurement Input, Exercise Price [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		2.03	2.03	2.03	2.03			2.03				2.03
Measurement Input, Exercise Price [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		2.03	2.03	2.03	2.03			2.03				2.03
Measurement Input, Exercise Price [Member] | Investor Warrants Issued in Connection with 2018 Financing [Member]
Fair value of the warrants	[2]						1.4927
Measurement Input, Exercise Price [Member] | Placement Agent Warrants Issued in Connection with 2018 Financing [Member]
Fair value of the warrants	[2]							1.4927				1.4927
Measurement Input, Quoted Price [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		0.297	0.064	0.37	0.70			1.25	[1]	4.02
Measurement Input, Quoted Price [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		0.287	0.061	0.36	0.65	[1]		1.18	[1]	3.96	[1]
Measurement Input, Quoted Price [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		0.195	0.033	0.46	0.80			1.40				0.74
Measurement Input, Quoted Price [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		0.211	0.036	0.49	0.80			1.40				0.74
Measurement Input, Quoted Price [Member] | Investor Warrants Issued in Connection with 2018 Financing [Member]
Fair value of the warrants	[2]						0.45
Measurement Input, Quoted Price [Member] | Placement Agent Warrants Issued in Connection with 2018 Financing [Member]
Fair value of the warrants	[2]							0.51				0.02

[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.