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Employee Stock Purchase Plan - Additional Information (Detail) - 2019 ESPP [Member] | 12 Months Ended
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Sep. 30, 2019 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Ordinary shares, discount rate | 10.00%
Number of ordinary shares issued | 0
Minimum [Member] |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Eligible employees contribution from their eligible compensation during each semi annual | 1.00%
Maximum [Member] |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Eligible employees contribution from their eligible compensation during each semi annual | 15.00%
Number of ordinary shares issued | 500,000

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