Revenue - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Revenue from External Customer [Line Items]
Sales	$ 500
Total sales	14,088	$ 16,883	$ 25,476	$ 33,741
Product
Revenue from External Customer [Line Items]
Sales	10,969	13,123	19,366	26,656
Total sales	10,976	13,146	19,384	26,705
Service
Revenue from External Customer [Line Items]
Sales	3,112	3,737	6,092	7,036
Total sales	3,112	3,737	6,092	7,036
Finance
Revenue from External Customer [Line Items]
Finance	7	23	18	49
High Performance Products Segment
Revenue from External Customer [Line Items]
Total sales	888	1,475	2,444	2,516
High Performance Products Segment | Product
Revenue from External Customer [Line Items]
Sales	716	922	1,892	1,689
Total sales	716	922	1,892	1,689
High Performance Products Segment | Service
Revenue from External Customer [Line Items]
Sales	172	553	552	827
Total sales	172	553	552	827
TS
Revenue from External Customer [Line Items]
Total sales	13,200	15,408	23,032	31,225
TS | U.K.
Revenue from External Customer [Line Items]
Total sales	331	268	1,821	947
TS | U.S.
Revenue from External Customer [Line Items]
Total sales	12,869	15,140	21,211	30,278
TS | Product
Revenue from External Customer [Line Items]
Sales	10,253	12,201	17,474	24,967
Total sales	10,260	12,224	17,492	25,016
TS | Product | U.K.
Revenue from External Customer [Line Items]
Sales	241	184	1,644	737
Total sales	241	184	1,644	737
TS | Product | U.S.
Revenue from External Customer [Line Items]
Sales	10,012	12,017	15,830	24,230
Total sales	10,019	12,040	15,848	24,279
TS | Service
Revenue from External Customer [Line Items]
Sales	2,940	3,184	5,540	6,209
Total sales	2,940	3,184	5,540	6,209
TS | Service | U.K.
Revenue from External Customer [Line Items]
Sales	90	84	177	210
Total sales	90	84	177	210
TS | Service | U.S.
Revenue from External Customer [Line Items]
Sales	2,850	3,100	5,363	5,999
Total sales	2,850	3,100	5,363	5,999
TS | Finance
Revenue from External Customer [Line Items]
Finance	7	23	18	49
TS | Finance | U.S.
Revenue from External Customer [Line Items]
Finance	$ 7	$ 23	$ 18	$ 49