Note 8 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Net operating loss carryforwards	$ 32,644	$ 31,777
Net operating loss carryforwards of foreign subsidiaries	374	374
Book over tax depreciation	(48)	(62)
Stock-based compensation expense	38	25
Other	124	128
Deferred tax assets	33,132	32,242
Valuation allowance for deferred tax assets	(33,132)	(32,242)
Deferred tax assets, net of allowance