Revenue Recognition - Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Revenue:
Total revenue	$ 19,244	$ 21,189
Product, accessories and parts
Revenue:
Total revenue	14,073	17,085
Total from Micro turbine Products
Revenue:
Total revenue	10,086
Accessories and parts
Revenue:
Total revenue	3,987
Service
Revenue:
Total revenue	5,171	$ 4,104
Total North America
Revenue:
Total revenue	9,543
United States
Revenue:
Total revenue	7,629
Mexico
Revenue:
Total revenue	1,241
All other North America
Revenue:
Total revenue	673
All other Europe
Revenue:
Total revenue	1,455
United Kingdom
Revenue:
Total revenue	2,549
Columbia
Revenue:
Total revenue	4,004
Asia
Revenue:
Total revenue	1,528
Australia
Revenue:
Total revenue	1,670
All other
Revenue:
Total revenue	$ 2,499