Goodwill - Schedule of Goodwill (Details) - USD ($)	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Goodwill [Line Items]
Beginning balance	$ 6,633,000
Goodwill	6,633,000	$ 13,595,000
Accumulated impairment losses		(6,962,000)
Ending Balance	6,633,000
Non-Segment Related
Goodwill [Line Items]
Goodwill		3,595,000
Accumulated impairment losses		(3,595,000)
Semiconductor
Goodwill [Line Items]
Impairment of goodwill	0
SiC/LED
Goodwill [Line Items]
Impairment of goodwill	0
Net Goodwill-Continuing Operations
Goodwill [Line Items]
Beginning balance	6,633,000
Goodwill	6,633,000	10,228,000
Accumulated impairment losses		(3,595,000)
Ending Balance	6,633,000
Net Goodwill-Continuing Operations | Semiconductor
Goodwill [Line Items]
Beginning balance	5,905,000
Goodwill	5,905,000	5,905,000
Ending Balance	5,905,000
Net Goodwill-Continuing Operations | SiC/LED
Goodwill [Line Items]
Beginning balance	728,000
Goodwill	728,000	728,000
Ending Balance	$ 728,000
Discontinued Operations
Goodwill [Line Items]
Goodwill		3,367,000
Accumulated impairment losses		$ (3,367,000)