Note 15 - Warrant Liabilities (Tables)

6 Months Ended

Jun. 30, 2022

Notes Tables

Schedule of Warrant Liabilities [Table Text Block]

	As of June 30, 2022		As of March 31, 2022		As of December 31, 2021		Change in Fair Value (gain)/loss
							Six Months Ended June 30, 2022			Three Months Ended June 30, 2022
	(US$’000)		(US$’000)		(US$’000)		(US$’000)			(US$’000)
Warrants issued in the 2021 Financing:
--Investor Warrants		167		626		964		(797	)		(459	)
--Placement Agent Warrants		22		84		132		(110	)		(62	)
Warrants issued in the 2020 Financing:
--Investor Warrants		57		449		795		(738	)		(392	)
--Placement Agent Warrants		11		85		148		(137	)		(74	)
Warrant Liabilities		257		1,244		2,039		(1,782	)		(987	)

									Change in Fair Value (gain)/loss
	As of June 31, 2021		As of March 31, 2021		As of February 18, 2021		As of December 31, 2020		Six Months Ended June 30, 2021			Three Months Ended June 30, 2021
	(US$’000)		(US$’000)		(US$’000)		(US$’000)		(US$’000)			(US$’000)
Warrants issued in the 2021 Financing:
--Investor Warrants		3,257		5,942		10,476		*		(7,219	)		(2,685	)
--Placement Agent Warrants		431		817		1,445		*		(1,014	)		(386	)
Warrants issued in the 2020 Financing:
--Investor Warrants		2,420		3,370		*		1,279		1,141			(950	)
--Placement Agent Warrants		423		590		*		224		199			(167	)
Warrants issued in the 2018 Financing:
--Placement Agent Warrants		66		200		*		2		64			(134	)
		6,597		10,919		11,921		1,505		(6,829	)		(4,322	)

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, 2022		5,001,705		2.36	$	3.02		5,001,705		2.36	$	3.02
Granted/Vested		-						-
Exercised		-						-
Balance, June 30, 2022 (Unaudited)		5,001,705		1.86	$	3.02		5,001,705		1.86	$	3.02

Warrant [Member]

Notes Tables

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

	2021 Investors Warrants									2021 Placement Agent Warrants
	June 30, 2022			March 31, 2022			December 31, 2021			June 30, 2022			March 31, 2022			December 31, 2021
Stock price	$	0.34		$	0.73		$	1.00		$	0.34		$	0.73		$	1.00
Years to maturity		2.13			2.38			2.63			2.13			2.38			2.63
Risk-free interest rate		2.97	%		2.35	%		0.87	%		2.97	%		2.35	%		0.87	%
Dividend yield		-			-			-			-			-			-
Expected volatility		124	%		121	%		115	%		124	%		121	%		115	%
Exercise Price	$	3.59		$	3.59		$	3.59		$	4.4875		$	4.4875		$	4.4875
Fair value of the warrant	$	0.064		$	0.24		$	0.37		$	0.061		$	0.23		$	0.36
Warrant Liabilities (US$’000)	$	167		$	626		$	964		$	22		$	84		$	132

	2021 Investors Warrants									2021 Placement Agent Warrants
	June 30, 2021			March 31, 2021			February 18, 2021*			June 30, 2021			March 31, 2021			February 18, 2021*
Stock price	$	2.00		$	2.64		$	4.48		$	2.00		$	2.64		$	4.48
Years to maturity		3.14			3.38			3.50			3.14			3.38			3.50
Risk-free interest rate		0.48	%		0.41	%		0.26	%		0.48	%		0.41	%		0.26	%
Dividend yield		-			-			-			-			-			-
Expected volatility		114	%		168	%		168	%		114	%		168	%		168	%
Exercise Price	$	3.59		$	3.59		$	3.59		$	4.4875		$	4.4875		$	4.4875
Fair value of the warrant	$	1.25		$	2.28		$	4.02		$	1.18		$	2.24		$	3.96
Warrant Liabilities (US$’000)	$	3,257		$	5,942		$	10,476		$	431		$	817		$	1,445

	2020 Investors Warrants									2020 Placement Agent Warrants
	June 30, 2022			March 31, 2022			December 31, 2021			June 30, 2022			March 31, 2022			December 31, 2021
Stock price	$	0.34		$	0.73		$	1.00		$	0.34		$	0.73		$	1.00
Years to maturity		1.45			1.70			1.95			1.45			1.70			1.95
Risk-free interest rate		2.79	%		2.23	%		0.72	%		2.79	%		2.23	%		0.72	%
Dividend yield		-			-			-			-			-			-
Expected volatility		107	%		127	%		128	%		107	%		127	%		128	%
Exercise Price	$	2.03		$	2.03		$	2.03		$	2.03		$	2.03		$	2.03
Fair value of the warrant	$	0.033		$	0.26		$	0.46		$	0.036		$	0.28		$	0.49
Warrant Liabilities (US$’000)	$	57		$	449		$	795		$	11		$	85		$	148

	2020 Investors Warrants									2020 Placement Agent Warrants
	June 30, 2021			March 31, 2021			December 31, 2020			June 30, 2021			March 31, 2021			December 31, 2020
Stock price	$	2.00		$	2.64		$	1.35		$	2.00		$	2.64		$	1.35
Years to maturity		2.45			2.70			2.95			2.45			2.70			2.95
Risk-free interest rate		0.34	%		0.29	%		0.17	%		0.34	%		0.29	%		0.17	%
Dividend yield		-			-			-			-			-			-
Expected volatility		120	%		120	%		102	%		120	%		120	%		102	%
Exercise Price	$	2.03		$	2.03		$	2.03		$	2.03		$	2.03		$	2.03
Fair value of the warrant	$	1.40		$	1.95		$	0.74		$	1.40		$	1.95		$	0.74
Warrant Liabilities (US$’000)	$	2,420		$	3,370		$	1,279		$	423		$	590		$	224

	2018 Placement Agent Warrants
	June 30, 2021			March 31, 2021			December 31, 2020
Stock price	$	2.00		$	2.64		$	1.35
Years to maturity		0.05			0.30			0.05
Risk-free interest rate		0.04	%		0.03	%		0.08	%
Dividend yield		-			-			-
Expected volatility		74	%		206	%		59	%
Exercise Price	$	1.4927		$	1.4927		$	1.4927
Fair value of the warrant	$	0.51		$	1.55		$	0.02
Warrant liabilities (US$’000)	$	66		$	200		$	2