Note 2 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	May 31, 2018
Accounts Receivable, Credit Loss Expense (Reversal)	$ 3	$ 20
Inventory Write-down	391	285
Depreciation, Total	685	768
Contingent Liability, Repayment of State and Local Grant Funds Received	463	200
Foreign Currency Transaction Gain (Loss), before Tax, Total	(3)	$ (165)
City of Rochester and State of New York [Member]
Covenant, Future Amount Receivable	$ 87		$ 550
Minimum [Member]
Property, Plant and Equipment, Useful Life	1 year
Maximum [Member]
Property, Plant and Equipment, Useful Life	10 years
Thermal Products and Mechanical Products [Member]
Equipment Leased To Customers Initial Term	180 days