Revenue Recognition - Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenue:
Total revenue	$ 67,636	$ 68,926
Product and accessories
Revenue:
Total revenue	36,517	35,338
Total from Micro turbine Products
Revenue:
Total revenue	34,121	33,790
Accessories and parts
Revenue:
Total revenue	2,396	1,548
Parts and service
Revenue:
Total revenue	31,119	33,588
Total North America
Revenue:
Total revenue	36,754	34,588
United States
Revenue:
Total revenue	32,502	31,082
Mexico
Revenue:
Total revenue	3,931	2,361
All other North America
Revenue:
Total revenue	321	1,145
Russia
Revenue:
Total revenue	3,577	3,653
All other Europe
Revenue:
Total revenue	13,659	12,858
Total Europe
Revenue:
Total revenue	17,236	16,511
Asia
Revenue:
Total revenue	6,087	4,074
Australia
Revenue:
Total revenue	3,165	4,559
All other
Revenue:
Total revenue	$ 4,394	$ 9,194