Note 8 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2022

Notes Tables

Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]

				Year Ended December 31,
	2020			2021			2022
		$			$			$
Cayman Islands		3,805			5,652			3,522
U.S.		33,266			34,318			13,144
PRC		5,912			6,368			7,253
BVI		20,873			18,336			12,831
Australia		(35	)		(36	)		(633	)
Loss before income tax		63,821			64,638			36,117

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

	Year Ended December 31,
	2020		2021		2022
		$		$		$
Current income tax		-		3,570		163
Deferred income tax		-		-		-
Income tax expenses		-		3,570		163

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

		Year Ended December 31,
	2020			2021			2022
		$			$			$
Loss before income tax		63,821			64,638			36,117
Expected income tax benefit		13,403			13,574			7,585
Tax rate difference		(4,653	)		(3,796	)		(2,253	)
Non-deductible expenses		(688	)		(788	)		812
Research tax credits		641			1,096			1,437
Non-taxable income		120			21			-
Tax preference		-			3,755			(667	)
Others		68			(262	)		(216	)
Current and deferred tax rate differences		-			-			672
R&D super deduction		-			-			389
Interest expenses		-			-			(315	)
Change in valuation allowance		(8,891	)		(17,170	)		(7,607	)
Total income tax expenses		-			(3,570	)		(163	)

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

	December 31,
	2021			2022
		$			$
Deferred tax assets:
Net operating loss carryforward		24,211			26,571
Deferral of tax deduction of R&D expenses		6,757			6,857
Mandatory R&D Capitalization		-			3,819
Share-based compensation		1,482			1,591
Deferred revenue		9,510			8,630
Research tax credits		4,063			5,295
Operating lease liabilities		422			1,043
Accruals and reserves		11			21
Total deferred tax assets		46,456			53,827
Deferred tax liabilities:
Unrealized gain		(37	)		(41	)
Depreciation		(254	)		(346	)
Operating lease right-of-use assets		(420	)		(1,153	)
Total deferred tax liabilities		(711	)		(1,540	)
Total gross deferred tax assets		45,745			52,287
Less: valuation allowance		(45,745	)		(52,287	)
Net deferred tax assets		-			-

Summary of Income Tax Contingencies [Table Text Block]

	Year Ended December 31,
	2020			2021		2022
		$			$		$
Beginning balance, as of January 1		956			730		1,065
Additions based on tax positions related to prior tax years		-			283		3,099
Reductions based on tax positions related to prior tax years		(226	)		-		(608	)
Additions based on tax positions related to current tax year		-			52		78
Ending balance, as of December 31
		730			1,065		3,634