Acquisitions - Summary of Changes to Goodwill Balance (Detail) $ in Millions	3 Months Ended
Dec. 31, 2018 USD ($)
Goodwill [Line Items]
Ending balance	$ 413.2
Counsyl Inc [Member]
Goodwill [Line Items]
Beginning balance	94.9
Fair value adjustment to equipment	0.7
Intangible adjustment	0.9
Working capital adjustment	(1.1)
Change in deferred tax liability	(0.3)
Ending balance	$ 95.1

Goodwill adjustment to deferred tax assets liabilities.

No definition available.

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- Definition

Goodwill, intangible adjustments.

+ References

No definition available.

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- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
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- Definition

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.

+ References

No definition available.

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- Definition

Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 16
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- Definition

Amount of transfers into (out of) an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
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