Note 5 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

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

	Year Ended December 31,
	2016		2017		2018
Cayman Islands		894		2,045		3,305
U.S.		9,840		80,008		23,347
PRC		1,338		11,341		6,742
BVI		-		2,498		22,979
Australia		473		496		1,101
Net loss before income taxes		12,545		96,388		57,474

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

	Year Ended December 31,
	2016			2017			2018
Net loss before income taxes		12,545			96,388			57,474
Expected income tax benefit		4,391			33,736			12,069
Tax rate differential		581			5,796			(2,121	)
Non-deductible expenses		(152	)		(25,299	)		(880	)
Deemed disposal gain*		-			(10,506	)		-
Impact of U.S. statutory tax rate change		-			(2,943	)		-
Non-taxable income		-			227			75
Others		(63	)		74			(143	)
Change in valuation allowance		(4,757	)		(1,085	)		(9,000	)
Total income tax benefit		-			-			-

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

	December 31,
	2017			2018
Deferred tax assets:
Net operating loss carryforward		7,244			13,403
Intangible asset		329			191
Deferral of tax deduction of R&D expense		1,239			2,891
Share based compensation		1,427			2,754
Less: valuation allowance		(10,239	)		(19,239	)
Net deferred tax assets		-			-