Reportable Segments - Schedule of Reportable Segment Information (Details) - USD ($) $ in Thousands		12 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
Net revenues		$ 113,315	$ 106,298	$ 85,205
Operating income (loss)		(14,970)	17,286	3,725
Depreciation and amortization		5,012	1,729	1,398
Identifiable assets		137,021	133,534
Continuing Operations
Segment Reporting Information [Line Items]
Capital expenditures		2,898	1,135	3,012
Depreciation and amortization		5,012	1,729	1,398
Operating Segments | Semiconductor
Segment Reporting Information [Line Items]
Net revenues		77,595	87,982	72,086
Operating income (loss)		6,907	20,672	8,585
Identifiable assets		72,466	75,622
Operating Segments | Semiconductor | Continuing Operations
Segment Reporting Information [Line Items]
Capital expenditures		345	452	2,264
Depreciation and amortization		886	1,101	905
Operating Segments | Material and Substrate
Segment Reporting Information [Line Items]
Net revenues		35,720	18,316	13,119
Operating income (loss)		(8,765)	3,728	278
Identifiable assets		61,576	22,032
Operating Segments | Material and Substrate | Continuing Operations
Segment Reporting Information [Line Items]
Capital expenditures		1,092	411	695
Depreciation and amortization		4,045	565	438
Non-Segment Related
Segment Reporting Information [Line Items]
Operating income (loss)		(13,112)	(7,114)	(5,138)
Identifiable assets	[1]	2,979	35,880
Non-Segment Related | Continuing Operations
Segment Reporting Information [Line Items]
Capital expenditures		1,461	272	53
Depreciation and amortization		$ 81	$ 63	$ 55

[1] Non-segment related assets include cash, property and other assets.