Revenue Recognition - Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Total revenue	$ 83,412	$ 82,837
Product, accessories and parts
Disaggregation of Revenue [Line Items]
Total revenue	66,303	66,754
Total from Micro turbine Products
Disaggregation of Revenue [Line Items]
Total revenue	51,417	50,813
Accessories and parts
Disaggregation of Revenue [Line Items]
Total revenue	14,886	15,941
Service
Disaggregation of Revenue [Line Items]
Total revenue	17,109	16,083
Total North America
Disaggregation of Revenue [Line Items]
Total revenue	51,276	41,265
United States
Disaggregation of Revenue [Line Items]
Total revenue	45,480	39,100
Mexico
Disaggregation of Revenue [Line Items]
Total revenue	5,005	2,007
All other North America
Disaggregation of Revenue [Line Items]
Total revenue	791	158
All other Europe
Disaggregation of Revenue [Line Items]
Total revenue	12,886	12,762
Total Europe
Disaggregation of Revenue [Line Items]
Total revenue	16,062	15,586
Asia
Disaggregation of Revenue [Line Items]
Total revenue	5,229	8,378
Australia
Disaggregation of Revenue [Line Items]
Total revenue	3,874	5,443
All other
Disaggregation of Revenue [Line Items]
Total revenue	$ 6,971	$ 12,165