Note 7 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Net operating loss carryforwards	$ 20,720	$ 21,175
Net operating loss carryforwards of foreign subsidiaries	374	374
Depreciation expense, asset	4
Depreciation expense, liability		(14)
Stock-based compensation expense	28	25
Other	78	94
Deferred tax assets	21,204	21,654
Valuation allowance for deferred tax assets	(21,204)	(21,654)
Deferred tax assets, net of allowance

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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