Note 2 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Inventory Write-down	$ 61	$ 47
Thermal Products and Mechanical Products [Member]
Equipment Leased To Customers Initial Term	180 days

Amount of loss from reductions in inventory due to subsequent measurement adjustments, including, but not limited to, physical deterioration, obsolescence, or changes in price levels.

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