Note 13 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

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

(in thousands)	2018			2017			2016
Domestic (United Kingdom)	$	12,623		$	18,171		$	(730	)
Foreign (United States)		(37,404	)		(49,763	)		(24,622	)
Loss from continuing operations before income taxes	$	(24,781	)	$	(31,592	)	$	(25,352	)

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

(in thousands)	2018			2017			2016
Current:
Federal	$	—		$	—		$	—
U.K.		(532	)		—			—
Japan		(45	)		(14	)		(85	)
China		(13	)		(39	)		(12	)
State		—			(46	)		(51	)
Total current provision		(590	)		(99	)		(148	)
Deferred:
Federal		30,665			—			752
U.K.		(1,343	)		(1,535	)		2,630
State		8,554			—			540
Total deferred benefit (expense)		37,876			(1,535	)		3,922
Income tax benefit (expense)	$	37,286		$	(1,634	)	$	3,774

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

	2018			2017			2016
Income tax rate		19.0	%		19.3	%		20.0	%
U.K. research and development credit		1.8			1.5			1.9
Effect of U.S. tax reform – Federal tax rate change		—			(69.2	)		—
Permanent items		1.0			5.9			(1.9	)
Prior period adjustments		(5.2	)		—			—
State taxes		9.2			9.6			4.9
Other		2.0			4.6			(1.5	)
Effect of foreign tax rate differential		2.9			28.0			13.1
Uncertain tax positions		(1.7	)		—			—
Valuation allowance		121.5			(5.0	)		(21.6	)
Effective income tax rate		150.5	%		(5.3	)%		14.9	%

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

(in thousands)	2018			2017
Deferred tax assets:
U.S. federal net operating losses	$	11,478		$	33,713
State net operating loss (net of federal)		2,865			8,450
U.S. federal research and development credit		849			587
U.K. net operating loss		496			1,894
Share options		1,724			2,611
Accrued liabilities		1,052			393
Intangible assets		—			2,392
State credits		512			377
Other		136			167
Total deferred tax assets		19,112			50,584
Valuation allowance		(17,991	)		(48,098	)
Total deferred tax assets	$	1,121		$	2,486
Deferred tax liabilities:
Other assets	$	(69	)	$	—
Total deferred tax liabilities	$	(69	)	$	—

Summary of Valuation Allowance [Table Text Block]

(in thousands)	2018			2017		2016
Beginning of year (January 1)	$	48,098		$	46,473	$	43,076
(Decrease) increase in valuation allowance		(30,107	)		1,625		3,397
End of year (December 31)	$	17,991		$	48,098	$	46,473

Summary of Income Tax Contingencies [Table Text Block]

Balance at December 31, 2017	$	—
Settlement/decreases related to tax positions taken during prior years		—
Increases related to tax positions taken during prior years		372
Increases related to tax positions taken during the current year		—
Balance at December 31, 2018	$	372