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Arrangement fee paid to the lender by the Company related to the Credit Agreement, recorded as a debt discount.

No definition available.

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Legal costs incurred related to the Credit Agreement, recorded as a debt discount.

No definition available.

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Represents a freestanding financial instrument that is not indexed to the Company's own shares.

No definition available.

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Pertains to the warrants issued to the Guarantor And Co-Guarantor of the Credit Agreement.

No definition available.

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Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Face (par) amount of debt instrument at time of issuance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Face (par) amount of the original debt instrument that was repurchased.

No definition available.

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	us-gaap_DebtInstrumentTerm
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Amount, after accumulated amortization, of debt discount.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
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Amount of the cost of borrowed funds accounted for as interest expense.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 835
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- References

No definition available.

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Name:	us-gaap_ClassOfWarrantOrRightAxis=bhvn_WarrantsIssuedCommonIssuedCoGuarantorInConnectionWithCreditAgreementMember
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