Revenue Recognition - Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Revenue:
Total revenue	$ 14,193	$ 19,244
Product, accessories and parts
Revenue:
Total revenue	8,936	14,073
Total from Micro turbine Products
Revenue:
Total revenue	6,126	10,086
Accessories and parts
Revenue:
Total revenue	2,810	3,987
Service
Revenue:
Total revenue	5,257	5,171
Total North America
Revenue:
Total revenue	9,007	9,543
United States
Revenue:
Total revenue	7,924	7,629
Mexico
Revenue:
Total revenue	1,033	1,241
All other North America
Revenue:
Total revenue	50	673
Russia
Revenue:
Total revenue	467	1,455
All other Europe
Revenue:
Total revenue	2,625	2,549
Total Europe
Revenue:
Total revenue	3,092	4,004
Asia
Revenue:
Total revenue	944	1,528
Australia
Revenue:
Total revenue	637	1,670
All other
Revenue:
Total revenue	$ 513	$ 2,499