Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Disaggregation of Revenue [Line Items]
Revenue	$ 19,242	$ 24,568	$ 40,541	$ 43,815
Revenue from Contract with Customer | Customer Concentration Risk | Transferred over Time
Disaggregation of Revenue [Line Items]
Concentration risk			49.00%	62.00%
North America
Disaggregation of Revenue [Line Items]
Revenue	14,353	20,426	$ 31,647	$ 36,288
Europe
Disaggregation of Revenue [Line Items]
Revenue	4,889	4,142	8,894	7,527
Fixed wing aircraft
Disaggregation of Revenue [Line Items]
Revenue	8,855	10,071	19,581	19,960
Rotorcraft
Disaggregation of Revenue [Line Items]
Revenue	3,513	4,371	7,894	7,914
Energy components for power generation units
Disaggregation of Revenue [Line Items]
Revenue	5,101	4,346	9,724	8,003
Commercial product and other revenue
Disaggregation of Revenue [Line Items]
Revenue	1,773	5,780	3,342	7,938
Commercial revenue
Disaggregation of Revenue [Line Items]
Revenue	11,361	9,506	21,542	17,866
Military revenue
Disaggregation of Revenue [Line Items]
Revenue	$ 7,881	$ 15,062	$ 18,999	$ 25,949