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Period Type:	instant

Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980

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Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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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.

No definition available.

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Data Type:	xbrli:stringItemType
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The net book value of the asset(s) sold in connection with the sale of the property to another party and lease back to the seller.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 40
-Section 55
-Paragraph 51
-URI http://asc.fasb.org/extlink&oid=82846721&loc=d3e51840-112757

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 40
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=77888430&loc=SL77919786-209982

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
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-Section 55
-Paragraph 52
-URI http://asc.fasb.org/extlink&oid=82846721&loc=d3e51843-112757

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
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-Section 55
-Paragraph 50
-URI http://asc.fasb.org/extlink&oid=82846721&loc=d3e51831-112757

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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Namespace Prefix:
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Namespace Prefix:
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Name:	us-gaap_OtherCommitmentsAxis=bhvn_PaymentRequiredCommencementOfPhase1ClinicalTrialMember
Namespace Prefix:
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Name:	us-gaap_OtherCommitmentsAxis=bhvn_PaymentRequiredCommencementOfPhase2ClinicalTrialMember
Namespace Prefix:
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