Note 4 - Income Taxes - Income Tax Effects of Temporary Differences That Comprise Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Noncurrent deferred tax assets (liabilities):
Accounts receivable	$ 46	$ 99
Other accrued expenses	339	587
Property, plant and equipment	(659)	(1,190)
Employee benefits	1,970	3,979
Contribution carryforward		181
AMT credit	1,192	1,205
Net operating loss	6,733	7,727
Gross non-current deferred tax assets	9,621	12,588
Less valuation allowance	(9,621)	(12,588)
Net noncurrent deferred tax assets