License and Other Agreements	9 Months Ended
Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
License and Other Agreements	License and Other Agreements Catalent Agreements for Rimegepant In January 2018, the Company entered into an exclusive world-wide license and development agreement with Catalent, Inc. pursuant to which the Company obtained certain license rights to the Zydis® ODT technology for use with rimegepant. If the Company obtains regulatory approval or launches a rimegepant product that utilizes the Zydis ODT technology, the Company is obligated to pay Catalent up to $1,500 upon the achievement of specified regulatory and commercial milestones. If the Company commercializes a rimegepant product that utilizes the Zydis ODT technology, the agreement permits the Company to purchase the commercial product from Catalent at a fixed price, inclusive of a royalty. Under the agreement, Catalent will not develop or manufacture a formulation of any oral CGRP compound using Zydis ODT technology for itself or a third party until 2031, subject to certain minimum commercial revenues. Under this agreement, the Company is responsible for conducting clinical trials and preparing and filing regulatory submissions. The Company has the right to sublicense its rights under the agreement subject to Catalent’s prior written consent. Catalent has the right to enforce the patents covering the Zydis technology and to defend any allegation that a formulation using Zydis technology, such as rimegepant, infringes a third party’s patent. This agreement terminates on a country-by-country basis upon the later of (i) 10 years after the launch of the most recently launched product in such country and (ii) the expiration of the last valid claim covering each product in such country, unless earlier voluntarily terminated by the Company. This agreement automatically extends for one-year terms unless either party gives advance notice of intent to terminate. In addition, Catalent may terminate the agreement either in its entirety or terminate the exclusive nature of this agreement on a country-by-country basis if the Company fails to meet specified development timelines, which it may extend in certain circumstances. In July 2018, the Company entered into a commercial supply agreement with Catalent pursuant to which Catalent will exclusively manufacture and supply the Company's worldwide requirements for rimegepant in the Zydis ODT delivery formulation, if the Company pursues and receives regulatory approval of this formulation of rimegepant, for an initial term of five years after its commercial launch with optional two-year renewal periods. Under the agreement, Catalent will supply the rimegepant Zydis ODT product at a fixed price, inclusive of a royalty, and will not develop or manufacture a formulation of any oral CGRP compound using Zydis ODT technology for itself or a third party for a specified period of time, subject to certain minimum commercial revenues. Amendment to License Agreement with Bristol-Myers Squibb Company In March 2018, the Company entered into an Amendment to License Agreement (the “BMS Amendment”) with BMS, which amends the License Agreement between the Company and BMS from July 2016 (the “Original License Agreement” and, as amended by the BMS Amendment, the “BMS License Agreement”). Under the BMS Amendment, the Company paid BMS an upfront payment of $50,000 in return for a low single-digit reduction in the royalties payable on net sales of rimegepant and a mid single-digit reduction in the royalties payable on net sales of BHV-3500, recorded in Research and Development expense in the Condensed Consolidated Statements of Operations and Comprehensive Loss. Under the Original License Agreement, the Company was obligated to make tiered royalty payments based on annual worldwide net sales of licensed products upon their approval and commercialization, with percentages in the low- to mid-teens. The BMS Amendment also removes BMS’s right of first negotiation to regain its intellectual property rights or enter into a license agreement with the Company following the Company’s receipt of topline data from its Phase 3 clinical trials with rimegepant, and clarifies that antibodies targeting CGRP are not prohibited as competitive compounds under the non-competition clause of the Original License Agreement. The BMS License Agreement continues to provide the Company with exclusive global development and commercialization rights to rimegepant, BHV-3500 and related CGRP molecules, as well as related know-how and intellectual property. The Company’s obligations to make development and commercial milestone payments to BMS under the Original License Agreement remain unchanged. Revenue Participation Right with RPI Finance Trust In June 2018, pursuant to the Funding Agreement entered into by the Company and RPI (Note 7), the Company granted to RPI the right to receive certain revenue participation payments, subject to certain reductions, based on the future global net sales of the Products, for each calendar quarter during the royalty term contemplated by the Funding Agreement, in exchange for $100,000 in cash. Specifically, the participation rate commences at 2.10 percent on annual global net sales of up to and equal to $1.5 billion, declining to 1.50 percent on annual global net sales exceeding $1.5 billion. In addition, the Company had the option to repurchase 100% of the Revenue Participation Right from RPI for a purchase price of $155,000, if the Company entered into a definitive agreement to consummate a change of control. The Company did not exercise the Buy-Back Option which expired in July 2018. License Agreement with AstraZeneca In September 2018, the Company entered into the AstraZeneca Agreement. Under the AstraZeneca Agreement, the Company paid AstraZeneca an upfront cash payment of $3,000 and 109,523 shares valued at $4,080 on the date of settlement, and is obligated to pay milestone payments to AstraZeneca totaling up to $55,000 upon the achievement of specified regulatory and commercial milestones and up to $50,000 upon the achievement of specified sales-based milestones. In addition, Biohaven will pay AstraZeneca tiered royalties ranging from high single-digit to low double-digits based on net sales of specified approved products, subject to specified reductions. AstraZeneca granted Biohaven exclusive worldwide rights to develop and commercialize AZD3241, an oral myeloperoxidase (“ MPO”) inhibitor that AstraZeneca progressed through Phase 2 clinical trials. Biohaven plans to conduct a Phase 3 clinical trial of this product candidate, which will now be referred to as BHV-3241, for the treatment of multiple system atrophy (“ MSA ”), a rare, rapidly progressive and fatal neurodegenerative disease with no cure or effective treatments. Biohaven is now solely responsible, and has agreed to use commercially reasonable efforts, for all development, regulatory and commercial activities related to BHV-3241. Biohaven may sublicense its rights under the Agreement and, if it does so, will be obligated to pay a portion of any milestone payments received from the sublicensee to AstraZeneca in addition to any milestone payments Biohaven would otherwise be obligated to pay. Biohaven is also now responsible for the prosecution and maintenance of the patents related to BHV-3241 and has the first right to prosecute infringement of the patents and defend challenges to the validity or enforceability of the patents. The Agreement terminates on a country-by-country basis and product-by-product basis upon the expiration of the royalty term for such product in such country. Each royalty term begins on the date of the first commercial sale of the licensed product in the applicable country and ends on the later of 10 years from such first commercial sale or the expiration of the last to expire of the applicable patents in that country. The Agreement may be terminated earlier in specified situations, including termination for uncured material breach of the Agreement by either party, termination by AstraZeneca in specified circumstances, termination by Biohaven on a country-by-country basis with advance notice and termination upon a party’s insolvency or bankruptcy. License Agreement with the University of Connecticut In October 2018, the Company announced it had signed an exclusive, worldwide option and license agreement (the "UConn Agreement") with the University of Connecticut ("UConn") for the development and commercialization rights to UC1MT, a therapeutic antibody targeting extracellular metallothionein. Under this agreement, Biohaven has the option to acquire an exclusive, worldwide license to UC1MT and its underlying patents to develop and commercialize throughout the world in all human indications. If the Company chooses to exercise the option, it would be obligated to pay UConn upon the achievement of specified regulatory and commercial milestones, and royalties of a low single-digit percentage of net sales of licensed products sold by the Company, its affiliates or its sublicensees.

In January 2018, the Company entered into an exclusive world-wide license and development agreement with Catalent, Inc. pursuant to which the Company obtained certain license rights to the Zydis® ODT technology for use with rimegepant. If the Company obtains regulatory approval or launches a rimegepant product that utilizes the Zydis ODT technology, the

Company is obligated to pay Catalent up to $1,500 upon the achievement of specified regulatory and commercial milestones. If the Company commercializes a rimegepant product that utilizes the Zydis ODT technology, the agreement permits the Company to purchase the commercial product from Catalent at a fixed price, inclusive of a royalty. Under the agreement, Catalent will not develop or manufacture a formulation of any oral CGRP compound using Zydis ODT technology for itself or a third party until 2031, subject to certain minimum commercial revenues.

Under this agreement, the Company is responsible for conducting clinical trials and preparing and filing regulatory submissions. The Company has the right to sublicense its rights under the agreement subject to Catalent’s prior written consent. Catalent has the right to enforce the patents covering the Zydis technology and to defend any allegation that a formulation using Zydis technology, such as rimegepant, infringes a third party’s patent.

This agreement terminates on a country-by-country basis upon the later of (i) 10 years after the launch of the most recently launched product in such country and (ii) the expiration of the last valid claim covering each product in such country, unless earlier voluntarily terminated by the Company. This agreement automatically extends for one-year terms unless either party gives advance notice of intent to terminate. In addition, Catalent may terminate the agreement either in its entirety or terminate the exclusive nature of this agreement on a country-by-country basis if the Company fails to meet specified development timelines, which it may extend in certain circumstances.

In July 2018, the Company entered into a commercial supply agreement with Catalent pursuant to which Catalent will exclusively manufacture and supply the Company's worldwide requirements for rimegepant in the Zydis ODT delivery formulation, if the Company pursues and receives regulatory approval of this formulation of rimegepant, for an initial term of five years after its commercial launch with optional two-year renewal periods. Under the agreement, Catalent will supply the rimegepant Zydis ODT product at a fixed price, inclusive of a royalty, and will not develop or manufacture a formulation of any oral CGRP compound using Zydis ODT technology for itself or a third party for a specified period of time, subject to certain minimum commercial revenues.

In March 2018, the Company entered into an Amendment to License Agreement (the “BMS Amendment”) with BMS, which amends the License Agreement between the Company and BMS from July 2016 (the “Original License Agreement” and, as amended by the BMS Amendment, the “BMS License Agreement”). Under the BMS Amendment, the Company paid BMS an upfront payment of $50,000 in return for a low single-digit reduction in the royalties payable on net sales of rimegepant and a mid single-digit reduction in the royalties payable on net sales of BHV-3500, recorded in Research and Development expense in the Condensed Consolidated Statements of Operations and Comprehensive Loss. Under the Original License Agreement, the Company was obligated to make tiered royalty payments based on annual worldwide net sales of licensed products upon their approval and commercialization, with percentages in the low- to mid-teens.

The BMS Amendment also removes BMS’s right of first negotiation to regain its intellectual property rights or enter into a license agreement with the Company following the Company’s receipt of topline data from its Phase 3 clinical trials with rimegepant, and clarifies that antibodies targeting CGRP are not prohibited as competitive compounds under the non-competition clause of the Original License Agreement.

The BMS License Agreement continues to provide the Company with exclusive global development and commercialization rights to rimegepant, BHV-3500 and related CGRP molecules, as well as related know-how and intellectual property. The Company’s obligations to make development and commercial milestone payments to BMS under the Original License Agreement remain unchanged.

In June 2018, pursuant to the Funding Agreement entered into by the Company and RPI (Note 7), the Company granted to RPI the right to receive certain revenue participation payments, subject to certain reductions, based on the future global net sales of the Products, for each calendar quarter during the royalty term contemplated by the Funding Agreement, in exchange for $100,000 in cash. Specifically, the participation rate commences at 2.10 percent on annual global net sales of up to and equal to $1.5 billion, declining to 1.50 percent on annual global net sales exceeding $1.5 billion.

In addition, the Company had the option to repurchase 100% of the Revenue Participation Right from RPI for a purchase price of $155,000, if the Company entered into a definitive agreement to consummate a change of control. The Company did not exercise the Buy-Back Option which expired in July 2018.

In September 2018, the Company entered into the AstraZeneca Agreement. Under the AstraZeneca Agreement, the Company paid AstraZeneca an upfront cash payment of $3,000 and 109,523 shares valued at $4,080 on the date of settlement, and is obligated to pay milestone payments to AstraZeneca totaling up to $55,000 upon the achievement of specified regulatory and commercial milestones and up to $50,000 upon the achievement of specified sales-based milestones. In addition, Biohaven will pay AstraZeneca tiered royalties ranging from high single-digit to low double-digits based on net sales of specified approved products, subject to specified reductions.

AstraZeneca granted Biohaven exclusive worldwide rights to develop and commercialize AZD3241, an oral myeloperoxidase (“ MPO”) inhibitor that AstraZeneca progressed through Phase 2 clinical trials. Biohaven plans to conduct a Phase 3 clinical trial of this product candidate, which will now be referred to as BHV-3241, for the treatment of multiple system atrophy (“ MSA ”), a rare, rapidly progressive and fatal neurodegenerative disease with no cure or effective treatments.

Biohaven is now solely responsible, and has agreed to use commercially reasonable efforts, for all development, regulatory and commercial activities related to BHV-3241. Biohaven may sublicense its rights under the Agreement and, if it does so, will be obligated to pay a portion of any milestone payments received from the sublicensee to AstraZeneca in addition to any milestone payments Biohaven would otherwise be obligated to pay. Biohaven is also now responsible for the prosecution and maintenance of the patents related to BHV-3241 and has the first right to prosecute infringement of the patents and defend challenges to the validity or enforceability of the patents.

The Agreement terminates on a country-by-country basis and product-by-product basis upon the expiration of the royalty term for such product in such country. Each royalty term begins on the date of the first commercial sale of the licensed product in the applicable country and ends on the later of 10 years from such first commercial sale or the expiration of the last to expire of the applicable patents in that country. The Agreement may be terminated earlier in specified situations, including termination for uncured material breach of the Agreement by either party, termination by AstraZeneca in specified circumstances, termination by Biohaven on a country-by-country basis with advance notice and termination upon a party’s insolvency or bankruptcy.