Note 16 - The Financing and Warrant Liabilities- Fair Value of Warrants (Details) $ in Thousands		Dec. 31, 2022 USD ($) yr	Dec. 31, 2021 USD ($) yr	Jul. 02, 2021 USD ($)	Feb. 18, 2021 USD ($) yr	[1]	Dec. 31, 2020 USD ($)
Proceeds allocated to warrant liabilities		$ 185	$ 2,039				$ 1,505
Investor Warrants Issued in Connection with 2021 Financing [Member]
Proceeds allocated to warrant liabilities		86	964		$ 10,476
Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Proceeds allocated to warrant liabilities		9	132		$ 1,445
Investor Warrants Issued in Connection with 2020 Financing [Member]
Proceeds allocated to warrant liabilities		76	795				1,279
Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Proceeds allocated to warrant liabilities		$ 14	148				224
Investor Warrants Issued in Connection with 2018 Financing [Member]
Proceeds allocated to warrant liabilities	[2]			$ 58
Placement Agent Warrants Issued in Connection with 2018 Financing [Member]
Proceeds allocated to warrant liabilities			$ 0	$ 58			$ 2
Measurement Input, Share Price [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		0.46	1.00		4.48
Measurement Input, Share Price [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		0.46	1.00		4.48
Measurement Input, Share Price [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		0.46	1.00				1.35
Measurement Input, Share Price [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		0.46	1.00				1.35
Measurement Input, Share Price [Member] | Investor Warrants Issued in Connection with 2018 Financing [Member]
Fair value of the warrants	[2],[3]			1.94
Measurement Input, Share Price [Member] | Placement Agent Warrants Issued in Connection with 2018 Financing [Member]
Fair value of the warrants	[3]						1.35
Measurement Input, Expected Term [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants | yr		1.63	2.63		3.50
Measurement Input, Expected Term [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants | yr		1.63	2.63		3.50
Measurement Input, Expected Term [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		0.95	1.95				2.95
Measurement Input, Expected Term [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		0.95	1.95				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							0.05
Measurement Input, Risk Free Interest Rate [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		0.04625	0.0087		0.0026
Measurement Input, Risk Free Interest Rate [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		0.04625	0.0087		0.0026
Measurement Input, Risk Free Interest Rate [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		0.04716	0.0072				0.0017
Measurement Input, Risk Free Interest Rate [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		0.04716	0.0072				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							0.0008
Measurement Input, Expected Dividend Rate [Member] | Investor Warrants Issued in Connection with 2018 Financing [Member]
Fair value of the warrants	[2]			0
Measurement Input, Expected Dividend Rate [Member] | Placement Agent Warrants Issued in Connection with 2018 Financing [Member]
Fair value of the warrants							0
Measurement Input, Price Volatility [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		0.9974	1.15		1.68
Measurement Input, Price Volatility [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		0.9974	1.15		1.68
Measurement Input, Price Volatility [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		1.1561	1.28				1.02
Measurement Input, Price Volatility [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		1.1561	1.28				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							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
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
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
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
Measurement Input, Exercise Price [Member] | Investor Warrants Issued in Connection with 2018 Financing [Member]
Fair value of the warrants	[2],[3]			1.4927
Measurement Input, Exercise Price [Member] | Placement Agent Warrants Issued in Connection with 2018 Financing [Member]
Fair value of the warrants	[3]						1.4927
Measurement Input, Quoted Price [Member] | Investor Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		0.0329	0.37		4.02
Measurement Input, Quoted Price [Member] | Placement Agent Warrants Issued in Connection with 2021 Financing [Member]
Fair value of the warrants		0.0256	0.36		3.96
Measurement Input, Quoted Price [Member] | Investor Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		0.0439	0.46				0.74
Measurement Input, Quoted Price [Member] | Placement Agent Warrants Issued in Connection with 2020 Financing [Member]
Fair value of the warrants		0.0456	0.49				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							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 on July 2, 2021. As a result, the Company issued approximately 0.008 million shares of the Company’s restricted common stock to the placement agent, with a loss of approximately US$0.02 million recognized in other income/(loss) account for the year ended December 31, 2021, which represented the difference between the fair value of these warrants on the date of the cashless exercise and the cost of the Company’s restricted common stock issued, based on the close bid price of the Company’s common stock on the same date.

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