Note 12 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

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

	Years Ended December 31,
	2018			2017			2016
United States of America	$	(25,375	)	$	(15,740	)	$	(7,595	)
International		(15,283	)		(14,744	)		(7,481	)
Loss before provision for income taxes	$	(40,658	)	$	(30,484	)	$	(15,076	)

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

	Years Ended December 31,
	2018			2017			2016
Current income tax provision
Federal	$	—		$	—		$	—
State		44			64			58
Foreign		940			1,301			1,708
Total current income tax provision		984			1,365			1,766
Deferred income tax benefit
Federal		—			—			—
State		—			—			—
Foreign		(398	)		(358	)		(362	)
Total deferred income tax benefit		(398	)		(358	)		(362	)
Provision for income taxes	$	586		$	1,007		$	1,404

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

	Years Ended December 31,
	2018			2017			2016
Tax benefit at U.S. statutory rate	$	(8,538	)	$	(10,365	)	$	(5,126	)
Foreign income and withholding taxes		4,247			5,578			4,317
Other permanent differences		3,807			974			—
State income taxes, net of federal benefit		(1,766	)		(2,858	)		(147	)
Change in valuation allowance		1,402			(8,158	)		155
Stock-based compensation		847			1,085			2,231
Research and development credits		(822	)		(382	)		(736	)
Provision to return adjustments		658			153			(484	)
Uncertain tax positions		224			1,995			1,146
Impact of change to U.S. statutory rate from Tax Cuts and Jobs Act		—			14,302			—
Recognition of tax windfalls related to stock-based compensation		—			(1,291	)		—
Other		527			(26	)		48
Provision for income taxes	$	586		$	1,007		$	1,404

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

	December 31,
	2018			2017
Net operating loss	$	27,192		$	25,002
Research and development credits		9,308			8,757
Stock-based compensation		2,519			2,796
Accruals and reserves		513			1,656
Property and equipment and intangible assets		(342	)		(710	)
Other		3,272			3,161
Net deferred tax assets		42,462			40,662
Valuation allowance		(42,626	)		(41,224	)
Total non-current net deferred tax liabilities, net of valuation allowance	$	(164	)	$	(562	)

Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]

Ending balance as of December 31, 2015	$	7,558
Decrease in balances related to tax positions taken during the current period		(2	)
Increase in balances related to tax positions taken during the prior period		1,240
Ending balance as of December 31, 2016		8,796
Increase in balances related to tax positions taken during the current period		1,738
Decrease in balances related to tax positions taken during the prior period		(9	)
Decrease in balances due to change in United States statutory rate		(2,101	)
Ending balance as of December 31, 2017		8,424
Increase in balances related to tax positions taken during the current period		778
Decrease in balances related to tax positions taken during the prior period		(812	)
Ending balance as of December 31, 2018	$	8,390