Revenue Recognition - Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Revenue:
Total revenue	$ 20,676	$ 17,383	$ 49,774	$ 57,366
Product, accessories and parts
Revenue:
Total revenue	15,374	12,010	33,654	42,070
Total from Micro turbine Products
Revenue:
Total revenue	12,224		25,397
Accessories and parts
Revenue:
Total revenue	3,150		8,257
Service
Revenue:
Total revenue	5,302	$ 5,373	16,120	$ 15,296
Total North America
Revenue:
Total revenue	10,811		26,434
United States
Revenue:
Total revenue	9,640		23,237
Mexico
Revenue:
Total revenue	1,091		3,017
All other North America
Revenue:
Total revenue	80		180
Russia
Revenue:
Total revenue	627		2,725
All other Europe
Revenue:
Total revenue	3,779		10,780
Total Europe
Revenue:
Total revenue	4,406		13,505
Asia
Revenue:
Total revenue	1,240		3,455
Australia
Revenue:
Total revenue	1,094		2,319
All other
Revenue:
Total revenue	$ 3,125		$ 4,061