Note 1 - Nature of Operations, Basis of Presentation and Company Conditions (Details Textual) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Apr. 18, 2019 USD ($)	Dec. 31, 2018 USD ($)
Number of Subsidiaries in Reportable Segments	3
Number of Categories in Product Offerings	2
Net Income (Loss) Attributable to Parent, Total	$ (3,003)	$ (3,261)
Net Cash Provided by (Used in) Operating Activities, Total	(2,721)	$ (2,903)
Retained Earnings (Accumulated Deficit), Ending Balance	(124,108)			$ (123,993)
Working Capital	$ 12,400
Bank of America [Member] | Subsequent Event [Member]
Line of Credit Facility, Maximum Borrowing Capacity			$ 10,000
Power and Electromechanical and Energy Segments [Member]
Number of Reportable Segments	2