Aggregate number of common shares reserved for future issuance.

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Weighted-average period over which cost not yet recognized is expected to be recognized for 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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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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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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Number of additional shares authorized for issuance under share-based payment arrangement.

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Number of shares authorized for issuance under share-based payment arrangement.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Gross number of share options (or share units) granted during the period.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Share based compensation arrangement by share based payment award expiration period condition one.

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Share-Based Compensation Arrangement By Share-Based Payment Award, Measurement Period, Percentage

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Share-Based Payment Arrangement, Number Of Plans

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Stock-Based Compensation - Narrative (Details) shares in Thousands, $ in Millions		12 Months Ended
	Feb. 25, 2003 shares	Sep. 30, 2020 USD ($) plan shares	Sep. 30, 2019 shares	Dec. 22, 2003 shares	Apr. 01, 2002 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock-based compensation plans \| plan		2
Granted (in shares)		0	210
RSU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period, condition one		1 year
Unrecognized stock compensation expense \| $		$ 1.8
Unrecognized stock compensation expense, period for recognition		2 years 4 months 24 days
RSU \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
RSU \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		4 years
PSU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock compensation expense \| $		$ 1.6
Unrecognized stock compensation expense, period for recognition		1 year 4 months 24 days
PSU \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Measurement period, percentage		0.00%
PSU \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Measurement period, percentage		150.00%
2002 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of options to purchase shares of common stock (in shares)					700
Number of additional shares authorized for issuance under an established share-based compensation plan (in shares)	100
2003 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of options to purchase shares of common stock (in shares)				6,300
Common stock reserved for issuance (in shares)		2,200
Available for future grant (in shares)		1,300
2003 Plan \| Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period, condition one		1 year
Expiration period, condition two		90 days
2003 Plan \| Stock Option \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration date		7 years
2003 Plan \| Stock Option \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration date		10 years