Amount of increase in additional paid in capital (APIC) resulting from reclassification of warrant liability to equity

No definition available.

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

Number of directors to whom the Company agreed to issue warrants to purchase common shares.

+ References

No definition available.

+ Details

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Namespace Prefix:	bhvn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of expense (income) related to adjustment to fair value of warrant liability.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section 25
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=109262497&loc=d3e20148-110875

+ Details

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Balance Type:	debit
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- Definition

Value of outstanding derivative securities that permit the holder the right to purchase securities (usually equity) from the issuer at a specified price.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(i))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

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Balance Type:	credit
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Warrants - Guarantor and Co-Guarantor Warrants (Details) $ in Thousands			3 Months Ended		6 Months Ended
	Jan. 26, 2018 USD ($)	Aug. 30, 2016 director	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Guarantor and Co-Guarantor Warrants
Number of directors to whom the Company agreed to issue warrants \| director		2
Reclassification of fair value of warrant liability to shareholders' equity	$ 5,203				$ 5,203	$ 0
Fair value of warrant liability			$ 0		0		$ 4,021
Income (expense) from change in fair value of warrant liability			$ 0	$ (2,629)	$ (1,182)	$ (3,083)
Directors
Guarantor and Co-Guarantor Warrants
Number of directors to whom the Company agreed to issue warrants \| director		2