Summary of Significant Accounting Policies and Going Concern - Segment Reporting - Revenue by Product (Details) - USD ($) $ in Thousands	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Mar. 31, 2022	Mar. 31, 2021
Revenue by product
Total Revenue	$ 16,049	$ 17,808	$ 17,640	$ 12,467	$ 18,135	$ 16,697	$ 13,710	$ 19,065	$ 30,107	$ 32,775	$ 47,915	$ 49,472	$ 63,964	$ 67,607
Product and accessories
Revenue by product
Total Revenue	8,236	9,901	9,344	5,239	$ 10,495	$ 8,848	$ 6,099	$ 11,209	14,583	$ 17,308	24,484	$ 26,156	32,720	36,651
Total from Micro turbine Products
Revenue by product
Total Revenue													31,367	34,367
C30
Revenue by product
Total Revenue													1,101	1,009
C65
Revenue by product
Total Revenue													8,763	9,989
C200
Revenue by product
Total Revenue													3,213	2,619
C600
Revenue by product
Total Revenue													6,899	6,707
C800
Revenue by product
Total Revenue													4,935	3,069
C1000
Revenue by product
Total Revenue													6,456	10,974
Accessories and parts
Revenue by product
Total Revenue													1,353	2,284
Parts and service
Revenue by product
Total Revenue	$ 7,813	$ 7,907	$ 8,296	$ 7,228					$ 15,524		$ 23,431		$ 31,244	$ 30,956