Stock-based Compensation - Fair Values of Options, Black-Scholes Option-Pricing Model, Weighted-Average Assumptions (Detail)	9 Months Ended
Jun. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Risk-free interest rate	0.44%
Expected volatility	48.15%
Expected life (in years)	5 years 4 months 9 days
Dividend yield	0.00%

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

Rate of weighted-average expected volatility for award under share-based payment arrangement.

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- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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