Note 2 - Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Revenues	$ 17,915	$ 14,134	$ 45,697	$ 41,618
Grid [Member]
Revenues	15,232	6,826	36,577	23,325
Grid [Member] | Americas [Member]
Revenues	10,164	3,771	28,663	16,319
Grid [Member] | Asia Pacific [Member]
Revenues	330	2,815	2,550	5,930
Grid [Member] | EMEA [Member]
Revenues	4,738	240	5,364	1,076
Wind [Member]
Revenues	2,683	7,308	9,120	18,293
Wind [Member] | Americas [Member]
Revenues	2	36	49	82
Wind [Member] | Asia Pacific [Member]
Revenues	2,647	7,263	8,968	18,136
Wind [Member] | EMEA [Member]
Revenues	34	9	104	75
Equipment and Systems [Member] | Grid [Member]
Revenues	14,040	4,614	32,438	17,571
Equipment and Systems [Member] | Wind [Member]
Revenues	2,160	7,215	7,742	17,925
Services and Technology Development [Member] | Grid [Member]
Revenues	1,192	2,212	4,139	5,754
Services and Technology Development [Member] | Wind [Member]
Revenues	$ 523	$ 93	$ 1,379	$ 368