Note 14 - Warrant Liabilities- Fair Value of Warrants (Details) $ in Thousands	Jun. 30, 2023 USD ($) yr		Mar. 31, 2023 USD ($) yr		Dec. 31, 2022 USD ($) yr		Jun. 30, 2022 USD ($) yr		Mar. 31, 2022 USD ($) yr		Dec. 31, 2021 USD ($) yr
Warrant liabilities as of the closing date	$ 13		$ 84				$ 257		$ 1,244
Investor Warrants Issued in Connection with 2021 Financing [Member]
Warrant liabilities as of the closing date	12		49		$ 86		167		626		$ 964
Investor Warrants Issued in Connection with 2020 Financing [Member]
Warrant liabilities as of the closing date	0		25		76		57		449		795
Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Warrant liabilities as of the closing date	1		5		9		22		84		132
Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Warrant liabilities as of the closing date	$ 0		$ 5		$ 14		$ 11		$ 85		$ 148
Measurement Input, Share Price [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants	1.27		1.70		0.46		0.34	[1]	0.73	[1]	1.00	[1]
Measurement Input, Share Price [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants	1.27		1.70		0.46		0.34	[1]	0.73	[1]	1.00	[1]
Measurement Input, Share Price [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants	1.27		1.70		0.46		0.34	[1]	0.73	[1]	1.00	[1]
Measurement Input, Share Price [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants	1.27		1.70		0.46		0.34	[1]	0.73	[1]	1.00	[1]
Measurement Input, Expected Term [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants | yr	1.13		1.38		1.63		2.13		2.38		2.63
Measurement Input, Expected Term [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants | yr	0.45		0.70		0.95		1.45		1.70		1.95
Measurement Input, Expected Term [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants | yr	1.13		1.38		1.63		2.13		2.38		2.63
Measurement Input, Expected Term [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants | yr	0.45		0.70		0.95		1.45		1.70		1.95
Measurement Input, Risk Free Interest Rate [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants	0.0534		0.0444		0.04625		0.0297		0.0235		0.0087
Measurement Input, Risk Free Interest Rate [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants	0.0546		0.0480		0.04716		0.0279		0.0223		0.0072
Measurement Input, Risk Free Interest Rate [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants	0.0534		0.0444		0.04625		0.0297		0.0235		0.0087
Measurement Input, Risk Free Interest Rate [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants	0.0546		0.0480		0.04716		0.0279		0.0223		0.0072
Measurement Input, Expected Dividend Rate [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants	0		0		0		0		0		0
Measurement Input, Expected Dividend Rate [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants	0		0		0		0		0		0
Measurement Input, Expected Dividend Rate [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants	0		0		0		0		0		0
Measurement Input, Expected Dividend Rate [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants	0		0		0		0		0		0
Measurement Input, Price Volatility [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants	1.12		1.13		0.9974		1.24		1.21		1.15
Measurement Input, Price Volatility [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants	0.94		1.25		1.1561		1.07		1.27		1.28
Measurement Input, Price Volatility [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants	1.12		1.13		0.9974		1.24		1.21		1.15
Measurement Input, Price Volatility [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants	0.94		1.25		1.1561		1.07		1.27		1.28
Measurement Input, Exercise Price [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants	17.95		17.95	[1]	3.59		3.59		3.59		3.59
Measurement Input, Exercise Price [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants	10.15		10.15	[1]	2.03		2.03		2.03		2.03
Measurement Input, Exercise Price [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants	22.4375	[1]	22.4375	[1]	4.4875	[1]	4.4875		4.4875		4.4875
Measurement Input, Exercise Price [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants	10.15	[1]	10.15	[1]	2.03	[1]	2.03		2.03		2.03
Measurement Input, Quoted Price [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants	0.0232		0.0937		0.0329		0.064		0.24		0.37
Measurement Input, Quoted Price [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants	0.000		0.0731		0.0439		0.033		0.26		0.46
Measurement Input, Quoted Price [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants	0.0157		0.0727		0.0256		0.061		0.23		0.36
Warrant liabilities as of the closing date							$ 167		$ 626
Measurement Input, Quoted Price [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants	0.000		0.0760		0.0456		0.036		0.28		0.49
Warrant liabilities as of the closing date	$ 0		$ 25				$ 57		$ 449

[1] To reflect the actual inputs used for the determination of fair value of the Warrants, the stock prices and exercise prices presented were not retrospectively restated for effect of the 1-for-5 reverse stock split effective on January 18, 2023, see Note 4(g).