Note 15 - Business Segments - Total Business Segments Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Mar. 31, 2020
Total assets	$ 111,227	$ 124,109
Operating Segments [Member] | Grid [Member]
Total assets	40,358	44,044
Operating Segments [Member] | Wind [Member]
Total assets	11,760	14,250
Corporate, Non-Segment [Member]
Total assets	$ 59,109	$ 65,815