Stock-based Compensation - Stock Options Outstanding (Details) - Stock Options - $ / shares	6 Months Ended
Mar. 31, 2020
Shares
Outstanding at beginning of period (shares)	523,754
Granted (shares)	950
Exercised (shares)	(126,492)
Forfeited (shares)	(2,350)
Outstanding at end of period (shares)	395,862
Exercisable at end of period (shares)	363,556
Vested or expected to vest in the future (shares)	394,502
Weighted Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 14.34
Granted (in dollars per share)	10.67
Exercised (in dollars per share)	11.05
Forfeited (in dollars per share)	9.70
Outstanding at end of period (in dollars per share)	15.42
Exercisable at end of period (in dollars per share)	15.65
Vested or expected to vest in the future (in dollars per share)	$ 15.43

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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

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Number of options outstanding, including both vested and non-vested options.

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-Publisher FASB
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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Number of share options (or share units) exercised during the current period.

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