Related Party Transactions - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Raw materials purchased from related party investor	$ 3.4	$ 3.2	$ 2.3
Description of related party transactions	During the years ended September 30, 2020, 2019, and 2018, the Company purchased raw materials from a related party investor in the amount of $3.4 million, $3.2 million, and $2.3 million, respectively. Payable balances and cash receipts and receivable balances with the related party were immaterial as of September 30, 2020, 2019, and 2018.

- Definition

A description of the related party transaction, including transactions to which no amounts or nominal amounts were ascribed and such other information deemed necessary to an understanding of the effects of the transactions on the financial statements. Examples of common related party transactions are, sales, purchases and transfers of realty and personal property, services received or furnished, loans and leases to and from top management and affiliates.

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