Goodwill and Intangible Assets - Narrative (Details) - USD ($)	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 1,000,000.0
Impairment of goodwill	0	$ 0	$ 0
Amortization of intangible assets	177,000	177,000	$ 205,000
Purchased Technology
Finite-Lived Intangible Assets [Line Items]
Purchased technology	$ 157,000	$ 334,000

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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