Summary of Significant Accounting Policies - Segment Reporting - Revenue by Product (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue by product
Total Revenue	$ 68,926	$ 83,412
Product, accessories and parts
Revenue by product
Total Revenue	48,143	66,303
Total from Micro turbine Products
Revenue by product
Total Revenue	33,790	51,417
C30
Revenue by product
Total Revenue	1,518	1,810
C65
Revenue by product
Total Revenue	9,366	11,719
C200
Revenue by product
Total Revenue	3,880	5,218
C600
Revenue by product
Total Revenue	7,204	6,286
C800
Revenue by product
Total Revenue	3,253	5,846
C1000
Revenue by product
Total Revenue	8,340	20,538
Unit upgrades
Revenue by product
Total Revenue	229
Accessories and parts
Revenue by product
Total Revenue	14,353	14,886
Service
Revenue by product
Total Revenue	$ 20,783	$ 17,109