Major Customers and Foreign Sales - Schedule of Revenues by Geographic Region (Details) - Net Revenues - Geographic Concentration Risk	6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenue, Major Customer [Line Items]
Concentration risk, percentage	100.00%	100.00%
United States
Revenue, Major Customer [Line Items]
Concentration risk, percentage	24.00%	34.00%
Other North America
Revenue, Major Customer [Line Items]
Concentration risk, percentage	3.00%	6.00%
Total North America
Revenue, Major Customer [Line Items]
Concentration risk, percentage	27.00%	40.00%
China
Revenue, Major Customer [Line Items]
Concentration risk, percentage	28.00%	24.00%
Malaysia
Revenue, Major Customer [Line Items]
Concentration risk, percentage	5.00%	4.00%
Taiwan
Revenue, Major Customer [Line Items]
Concentration risk, percentage	20.00%	11.00%
Other Asia
Revenue, Major Customer [Line Items]
Concentration risk, percentage	8.00%	7.00%
Total Asia
Revenue, Major Customer [Line Items]
Concentration risk, percentage	61.00%	46.00%
Germany
Revenue, Major Customer [Line Items]
Concentration risk, percentage	3.00%	3.00%
Other Europe
Revenue, Major Customer [Line Items]
Concentration risk, percentage	9.00%	11.00%
Total Europe
Revenue, Major Customer [Line Items]
Concentration risk, percentage	12.00%	14.00%