Note 2 - Summary of Significant Accounting Policies - Revenues Disaggregated (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues	$ 23,492	$ 20,342	$ 18,843
Power and Electromechanical Segment [Member]
Revenues	23,492
Power and Electromechanical Segment [Member] | North America [Member]
Revenues	9,654
Power and Electromechanical Segment [Member] | Europe [Member]
Revenues	13,733
Power and Electromechanical Segment [Member] | Asia [Member]
Revenues	42
Power and Electromechanical Segment [Member] | Other Regions [Member]
Revenues	63
Power and Electromechanical Segment [Member] | Transferred at Point in Time [Member]
Revenues	6,800
Power and Electromechanical Segment [Member] | Transferred over Time [Member]
Revenues	$ 16,692
Energy Segment [Member]
Revenues		20,342
Energy Segment [Member] | North America [Member]
Revenues		4,311
Energy Segment [Member] | Europe [Member]
Revenues		15,620
Energy Segment [Member] | Asia [Member]
Revenues		205
Energy Segment [Member] | Other Regions [Member]
Revenues		206
Energy Segment [Member] | Transferred at Point in Time [Member]
Revenues		4,391
Energy Segment [Member] | Transferred over Time [Member]
Revenues		$ 15,951