Business Acquisition revenue from acquiree.

No definition available.

Name:	extr_BusinessAcquisitionRevenueFromAcquiree
Namespace Prefix:	extr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Business combination acquisition compensation charge

+ References

No definition available.

+ Details

Name:	extr_BusinessCombinationAcquisitionCompensationCharge
Namespace Prefix:	extr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Date when the acquirer obtains control of the acquiree, in CCYY-MM-DD format.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 7
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Topic 805
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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

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Balance Type:	na
Period Type:	duration

- 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.

+ Details

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 23
-URI http://asc.fasb.org/extlink&oid=116868678&loc=d3e1043-128460

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
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-Topic 805
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+ Details

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- Details

Name:	us-gaap_BusinessAcquisitionAxis=extr_AerohiveNetworksIncMember
Namespace Prefix:
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Balance Type:
Period Type:

Business Combination (Narratives) (Details) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
	Aug. 09, 2019	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Acquisition and integration related expenses		$ 8,994		$ 67	$ 24,919	$ 2,613
Aerohive Networks, Inc.
Business Acquisition [Line Items]
Business acquisition, cash consideration	$ 267,146
Business acquisition, date of acquisition	Aug. 09, 2019
Revenue		41,900			67,300
Acquisition and integration related expenses		$ 9,000			$ 24,900
Compensation charge associated with acquisition			$ 6,800