Stock-based compensation - Reserved For Issuance (Detail) shares in Thousands	6 Months Ended
Mar. 31, 2022 shares
Share-Based Compensation Arrangement By Share-based Payment Award, Outstanding [Roll Forward]
Beginning balance (in shares)	355
Additional shares authorized (in shares)	249
Shares issued during the period (in shares)	(50)
Ending balance (in shares)	554

Share-Based Compensation Arrangement By Share-based Payment Award, Outstanding

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- Definition

Aggregate number of common shares reserved for future issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

Number of shares issued under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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