Note 14 - Warrant Liabilities (Tables)

3 Months Ended

Mar. 31, 2023

Notes Tables

Schedule of Warrant Liabilities [Table Text Block]

	As of March 31, 2023		As of December 31, 2022		Change in Fair Value (Gain)/Loss
	(US$’000)		(US$’000)		(US$’000)
Fair value of the Warrants:
Warrants issued in the 2021 Financing：
--Investor Warrants		49		86		(37	)
--Placement Agent Warrants		5		9		(4	)
Warrants issued in the 2020 Financing:
--Investor Warrants		25		76		(51	)
--Placement Agent Warrants		5		14		(9	)
Warrant liabilities		84		185		(101	)

	As of March 31, 2022		As of December 31, 2021		Change in Fair Value (Gain)/Loss
	(US$’000)		(US$’000)		(US$’000)
Fair value of the Warrants:
Warrants issued in the 2021 Financing：
--Investor Warrants		626		964		(338	)
--Placement Agent Warrants		84		132		(48	)
Warrants issued in the 2020 Financing:
--Investor Warrants		449		795		(346	)
--Placement Agent Warrants		85		148		(63	)
Warrant liabilities		1,244		2,039		(795	)

Schedule of Warrant Activity [Table Text Block]

	Warrant Outstanding						Warrant Exercisable
	Number of underlying shares		Weighted Average Remaining Contractual Life (Years)		Weighted Average Exercise Price		Number of underlying shares		Weighted Average Remaining Contractual Life (Years)		Weighted Average Exercise Price
Balance, January 1, 2023		1,000,343		1.36	$	15.11		1,001,343		1.36	$	15.11
Granted/Vested		-						-
Exercised		-						-
Balance, March 31, 2023 (Unaudited)		1,000,343		1.11	$	15.11		1,000,343		1.11	$	15.11

Warrant [Member]

Notes Tables

Fair Value Measurement Inputs and Valuation Techniques [Table Text Block]

	2021 Investor Warrants						2021 Placement Agent Warrants
	March 31, 2023			December 31, 2022			March 31, 2023			December 31, 2022
Stock price	$	1.70		$	0.46	#	$	1.70		$	0.46	#
Years to maturity		1.38			1.63			1.38			1.63
Risk-free interest rate		4.44	%		4.625	%		4.44	%		4.625	%
Dividend yield		-			-			-			-
Expected volatility		113	%		99.74	%		113	%		99.74	%
Exercise Price	$	17.95		$	3.59	#	$	22.4375		$	4.4875	#
Fair value of the warrant	$	0.0937		$	0.0329		$	0.0727		$	0.0256
Warrant liabilities (US$’000)	$	49		$	86		$	5		$	9

	2021 Investor Warrants						2021 Placement Agent Warrants
	March 31, 2022			December 31, 2021			March 31, 2022			December 31, 2021
Stock price#	$	0.73		$	1.00		$	0.73		$	1.00
Years to maturity		2.38			2.63			2.38			2.63
Risk-free interest rate		2.35	%		0.87	%		2.35	%		0.87	%
Dividend yield		-			-			-			-
Expected volatility		121	%		115	%		121	%		115	%
Exercise Price#	$	3.59		$	3.59		$	4.4875		$	4.4875
Fair value of the warrant	$	0.24		$	0.37		$	0.23		$	0.36
Warrant liabilities (US$’000)	$	626		$	964		$	84		$	132

	2020 Investor Warrants						2020 Placement Agent Warrants
	March 31, 2023			December 31, 2022			March 31, 2023			December 31, 2022
Stock price	$	1.70		$	0.46	#	$	1.70		$	0.46	#
Years to maturity		0.70			0.95			0.70			0.95
Risk-free interest rate		4.80	%		4.716	%		4.80	%		4.716	%
Dividend yield		-			-			-			-
Expected volatility		125	%		115.61	%		125	%		115.61	%
Exercise Price	$	10.15		$	2.03	#	$	10.15		$	2.03	#
Fair value of the warrant	$	0.0731		$	0.0439		$	0.0760		$	0.0456
Warrant liabilities (US$’000)	$	25		$	76		$	5		$	14

	2020 Investor Warrants						2020 Placement Agent Warrants
	March 31, 2022			December 31, 2021			March 31, 2022			December 31, 2021
Stock price#	$	0.73		$	1.00		$	0.73		$	1.00
Years to maturity		1.70			1.95			1.70			1.95
Risk-free interest rate		2.23	%		0.72	%		2.23	%		0.72	%
Dividend yield		-			-			-			-
Expected volatility		127	%		128	%		127	%		128	%
Exercise Price#	$	2.03		$	2.03		$	2.03		$	2.03
Fair value of the warrant	$	0.26		$	0.46		$	0.28		$	0.49
Warrant liabilities (US$’000)	$	449		$	795		$	85		$	148