Revenue Recognition - Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Revenue:
Total revenue	$ 17,383	$ 18,030	$ 57,366	$ 61,393
Product, accessories and parts
Revenue:
Total revenue	12,010	13,310	42,070	49,022
Total from Micro turbine Products
Revenue:
Total revenue	7,923		30,024
Accessories and parts
Revenue:
Total revenue	4,087		12,046
Service
Revenue:
Total revenue	5,373	$ 4,720	15,296	$ 12,371
Total North America
Revenue:
Total revenue	7,429		27,131
United States
Revenue:
Total revenue	7,030		24,497
Mexico
Revenue:
Total revenue	358		1,841
All other North America
Revenue:
Total revenue	41		793
All other Europe
Revenue:
Total revenue	4,060		11,077
Total Europe
Revenue:
Total revenue	5,242		14,544
Asia
Revenue:
Total revenue	1,162		3,611
Australia
Revenue:
Total revenue	1,867		4,005
Russia
Revenue:
Total revenue	1,182		3,467
All other
Revenue:
Total revenue	$ 1,683		$ 8,075