For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
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-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

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Reportable Segment Information - Geographic Revenue and Long-lived Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
U.S. [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	$ 25,920	$ 25,273
Ireland [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, net	$ 41,224	$ 18,113
Revenue [Member] \| Geographic Concentration Risk [Member] \| Domestic [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Percentage of consolidated revenue	79.00%	78.00%	81.00%
Revenue [Member] \| Geographic Concentration Risk [Member] \| Foreign [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Percentage of consolidated revenue	21.00%	22.00%	19.00%