Biohaven Pharmaceutical Holding 10-Q 16 Jun 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2017	Jun. 15, 2017
Document and Entity Information
Entity Registrant Name	Biohaven Pharmaceutical Holding Co Ltd.
Entity Central Index Key	1,689,813
Document Type	10-Q
Document Period End Date	Mar. 31, 2017
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	No
Entity Filer Category	Non-accelerated Filer
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1
Entity Common Stock, Shares Outstanding		35,748,083

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash	$ 52,286	$ 23,565
Restricted cash		67
Prepaid expenses and other current assets	883	403
Total current assets	53,169	24,035
Property and equipment, net	43	26
Deferred offering costs	2,399	134
Equity method investment (Note 5)	4,511	2,753
Restricted cash	60	60
Deferred tax assets	9	9
Total assets	60,191	27,017
Current liabilities:
Notes Payable, net of discount	4,489	4,216
Accounts payable	4,022	746
Accrued expenses	6,931	2,980
Total current liabilities	15,442	7,942
Warrant liability	1,234	780
Derivative liability	223	512
Contingent equity liability	22,313	18,938
Notes payable to related parties	602	595
Other long-term liabilities	19	13
Total liabilities	39,833	28,780
Commitments and contingencies (Note 14)
Series A convertible preferred shares, no par value; 11,242,172 shares authorized as of March 31, 2017 and December 31, 2016; 9,358,560 and 4,948,369 shares issued and outstanding as of March 31, 2017 and Dcember 31, 2016, respectively; aggregate liquidation preference of $86,951 and $45,976 as of March 31, 2017 and December 31, 2016, respectively	73,900	43,270
Shareholders' equity (deficit):
Common stock, no par value; 38,000,000 shares authorized as of March 31, 2017 and December 31, 2016; 13,121,000 and 13,088,500 shares issued and outstanding as of March 31, 2017 and December 31, 2016, respectively	20,296	19,944
Additional paid-in capital	20,371	10,479
Accumulated deficit	(94,209)	(75,456)
Total shareholders' equity (deficit)	(53,542)	(45,033)
Total liabilities, convertible preferred shares and shareholders' equity (deficit)	$ 60,191	$ 27,017

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
CONSOLIDATED BALANCE SHEETS
Preferred stock, par value (in dollars per share)	$ 0	$ 0
Preferred stock, shares authorized	11,242,172	11,242,172
Preferred stock, shares issued	9,358,560	4,948,369
Preferred stock, shares outstanding	9,358,560	4,948,369
Aggregate liquidation preference	$ 86,951	$ 45,976
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized	38,000,000	38,000,000
Common stock, shares issued	13,121,000	13,088,500
Common stock, shares outstanding	13,121,000	13,088,500

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating expenses:
Research and development	$ 10,740	$ 2,370
General and administrative	3,757	613
Total operating expenses	14,497	2,983
Loss from operations	(14,497)	(2,983)
Other income (expense):
Interest expense	(305)
Change in fair value of warrant liability	(454)
Change in fair value of derivative liability	289	(3)
Change in fair value of contingent equity liability	(3,375)
Loss from equity method investment	(218)
Total other income (expense), net	(4,063)	(3)
Loss before provision for income taxes	(18,560)	(2,986)
Provision for income taxes	193
Net loss and comprehensive loss	(18,753)	(2,986)
Net loss attributable to non-controlling interests		35
Accretion of beneficial conversion feature on series A preferred shares	(4,000)
Net loss attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd.	$ (22,753)	$ (2,951)
Net loss per share attributable to common share holders of Biohaven Pharmaceutical Holding Company Ltd.-basic and diluted	$ (1.74)	$ (0.25)
Weighted average common shares outstanding-basic and diluted	13,088,861	11,776,429

CONSOLIDATED STATEMENT OF CONVE

CONSOLIDATED STATEMENT OF CONVERTIBLE PREFERRED SHARES AND SHAREHOLDERS' EQUITY (DEFICIT) - 3 months ended Mar. 31, 2017 - USD ($) $ in Thousands	Series A Convertible Preferred Shares	Common Shares	Additional Paid-in Capital	Accumulated Deficit	Total
Balance, beginning of period at Dec. 31, 2016	$ 43,270				$ 43,270
Balance, beginning of period (in shares) at Dec. 31, 2016	4,948,369
Increase (decrease) in temporary equity
Issuance of Series A preferred shares, net offering costs of $1364	$ 38,636
Issuance of Series A preferred shares, net offering costs of $1364 (in shares)	4,305,182
Issuance of Series A preferred shares as payment of offering costs	105,009
Beneficial conversion feature on Series A preferred shares	$ (12,006)
Accretion of beneficial conversion feature on Series A preferred shares	4,000
Balance, end of period at Mar. 31, 2017	$ 73,900				73,900
Balance, end of period (in shares) at Mar. 31, 2017	9,358,560
Balances at Dec. 31, 2016		$ 19,944	$ 10,479	$ (75,456)	(45,033)
Balances (in shares) at Dec. 31, 2016		13,088,500
Increase (Decrease) in Stockholders' Equity
Issuance of common shares as payment for equity investment (Note 5)		$ 352			352
Issuance of common shares as payment for equity investment (Note 5) (in shares)		32,500
Beneficial conversion feature on Series A preferred shares			12,006		12,006
Accretion of beneficial conversion feature on series A preferred shares	$ 4,000		(4,000)		(4,000)
Share-based compensation expense			1,886		1,886
Net Loss				(18,753)	(18,753)
Balances at Mar. 31, 2017		$ 20,296	$ 20,371	$ (94,209)	$ (53,542)
Balances (in shares) at Mar. 31, 2017		13,121,000

CONSOLIDATED STATEMENT OF CONV6

CONSOLIDATED STATEMENT OF CONVERTIBLE PREFERRED SHARES AND SHAREHOLDERS' EQUITY (DEFICIT) (PARENTHETICAL) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended
	Feb. 28, 2017	Oct. 31, 2016	Mar. 31, 2017
Series A Convertible Preferred Shares
Issuance of common stock, issuance costs	$ 1,364	$ 1,730	$ 1,364

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net Loss	$ (18,753)	$ (2,986)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	1,886	687
Depreciation expense	4	1
Non-cash interest expense	280
Change in fair value of warrant liability	454
Change in fair value of derivative liability	(289)	3
Change in fair value of contingent equity liability	3,375
Loss from equity method investment	218
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(480)	125
Accounts payable	2,656	63
Accrued expenses	2,991	562
Other long-term liabilities	6
Net cash used in operating activities	(7,652)	(1,545)
Cash flows from investing activities:
Purchases of property and equipment	(21)
Purchase of equity method investment	(1,624)
Decrease in restricted cash	67
Net cash used in investing activities	(1,578)
Cash flows from financing activities:
Proceeds from issuance of common shares		3,003
Proceeds from issuance of Series A preferred shares	40,000
Payments of offering costs	(2,049)	(23)
Net cash provided by financing activities	37,951	2,980
Net increase in cash	28,721	1,435
Cash at beginning of period	23,565	1,460
Cash at end of period	52,286	$ 2,895
Supplemental disclosure of cash flow information:
Cash paid for interest	25
Supplemental disclosure of non-cash investing and financing activities:
Deferred offering costs included in accounts payable and accrued expenses	1,515
Deferred Series A offering costs included in accrued expenses	65
Beneficial conversion feature on Series A preferred shares	12,006
Accretion of beneficial conversion feature on series A preferred shares	(4,000)
Issuance of Series A preferred shares as payment of offering costs	1,242
Issuance of common shares as payment for equity investment (Note 5)	$ 352

Nature of the Business and Basi

Nature of the Business and Basis of Presentation	3 Months Ended
	Mar. 31, 2017
Nature of the Business and Basis of Presentation
Nature of the Business and Basis of Presentation	1. Nature of the Business and Basis of Presentation Biohaven Pharmaceutical Holding Company Ltd. (the “Company”) was incorporated in Tortola, British Virgin Islands in September 2013. The Company is a clinical-stage biopharmaceutical company with a portfolio of innovative, late-stage product candidates targeting neurologic diseases, including rare disorders. The Company’s product candidates are small molecules based on two distinct mechanistic platforms—calcitonin gene-related peptide (“CGRP”) receptor antagonists and glutamate modulators—which the Company believes have the potential to significantly alter existing treatment approaches across a diverse set of neurological indications with high unmet need in both large markets and orphan indications. The most advanced product candidate from the Company’s CGRP receptor antagonist platform is rimegepant, which the Company is developing for the acute treatment of migraine and for which it intends to initiate two Phase 3 clinical trials in the second half of 2017. The most advanced product candidate from the Company’s glutamate modulation platform is trigriluzole, which the Company is developing for the treatment of ataxias with an initial focus on spinocerebellar ataxia (“SCA”). The Company has received both orphan drug designation and fast track designation from the U.S. Food and Drug Administration (“FDA”) for trigriluzole in SCA, and the Company began a Phase 2/3 clinical trial in SCA in December 2016. The Company’s second most advanced product candidate from its glutamate modulation platform is BHV-0223, which the Company is developing for the treatment of amyotrophic lateral sclerosis (“ALS”), a neurodegenerative disease that affects nerve cells in the brain and spinal cord. The Company has received orphan drug designation from the FDA for BHV-0223 in ALS. The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations and the ability to secure additional capital to fund operations. Product candidates currently under development will require significant additional research and development efforts, including preclinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. The Company has historically outsourced all of the research and clinical development for its programs under a master services agreement (the “MSA”) with Biohaven Pharmaceuticals, Inc. (“BPI”). BPI was incorporated in the state of Delaware in July 2013. The three founders of BPI, each of whom beneficially owned one-third of the equity of BPI prior to the Company’s acquisition of BPI on December 31, 2016 (see Note 15), are shareholders of the Company and also serve as the Company’s Chairman of the board of directors, Chief Executive Officer, and Chief Medical Officer, respectively (see Note 15). BPI is a contract research organization (“CRO”) whose only customer is the Company. Since its incorporation, substantially all of the operations of BPI have been performed in service to the Company under the terms of the MSA, and substantially all of the funding for the operations of BPI was provided by the Company. The Company has determined that (i) it has the authority to direct the activities of BPI that most significantly impact the economics of the entity and (ii) the equity at risk in BPI is insufficient to finance its operations. As a result, the Company is deemed to have had a variable interest in BPI, and BPI is deemed to be a variable interest entity (“VIE”) of which the Company is the primary beneficiary. Accordingly, since the date of the Company’s incorporation in September 2013, the Company has consolidated the results of BPI. Upon original consolidation, the Company applied purchase accounting by recording the fair values of BPI’s assets acquired and liabilities assumed, which were determined to be zero because BPI had not yet commenced any operations. For the three months ended March 2016, 100% of the equity in BPI was reflected as a net loss attributable to non-controlling interest on the consolidated statement of operations and comprehensive loss. On December 31, 2016, the Company acquired 100% of the issued and outstanding shares of BPI (see Note 16), and as a result, for periods subsequent to the acquisition, the Company no longer reports any non-controlling interest related to BPI. The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (‘‘GAAP’’) and include the accounts of the Company and its subsidiaries after elimination of all significant intercompany accounts and transactions. Stock Split In October 2016, the Company effected a 500-for-one stock split of its issued and outstanding common shares. Accordingly, all share and per share amounts for all periods presented in the accompanying consolidated financial statements and notes thereto have been adjusted retroactively, where applicable, to reflect this stock split. Initial Public Offering On May 3, 2017, the Company’s registration statement on Form S-1 relating to its initial public offering of its common shares (the “IPO”) was declared effective by the Securities and Exchange Commission (“SEC”). The IPO closed on May 9, 2017 and the Company issued and sold 9,900,000 common shares at a public offering price of $17.00 per share (see note 17) for net proceeds of $152,889 after deducting underwriting discounts and commissions of $11,781 and other offering expenses of approximately $3,630. Upon the closing of the IPO, all convertible preferred shares then outstanding converted into an aggregate of 9,358,560 common shares. In addition, on May 9, 2017, the underwriters of the IPO fully exercised their option to purchase additional shares, and on May 11, 2017, the Company issued and sold 1,485,000 additional common shares for additional net proceeds of $23,478 after deducting underwriting discounts and commissions of $1,767. Thus, the aggregate net proceeds to the Company from the IPO, after deducting underwriting discounts and commissions and other offering costs, were $176,367. In connection with the completion of its IPO, the Company issued an additional aggregate of 1,883,523 common shares to BMS and AstraZeneca in satisfaction of obligations to contingently issue equity securities pursuant to the license agreements (see Note 12) for no additional consideration. Also in connection with the completion of its IPO in May 2017, the Company amended its memorandum and articles of association to authorize the issuance of up to 200,000,000 no par value common shares and 10,000,000 no par value undesignated preferred shares. Going Concern In accordance with Accounting Standards Update (“ASU”) 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (Subtopic 205-40), management must evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the financial statements are issued. This evaluation initially does not take into consideration the potential mitigating effect of management’s plans that have not been fully implemented as of the date the financial statements are issued. When substantial doubt exists under this methodology, management evaluates whether the mitigating effect of its plans sufficiently alleviates substantial doubt about the Company’s ability to continue as a going concern. The mitigating effect of management’s plans, however, is only considered if both (1) it is probable that the plans will be effectively implemented within one year after the date that the financial statements are issued, and (2) it is probable that the plans, when implemented, will mitigate the relevant conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued. Generally, to be considered probable of being effectively implemented, the plans must have been approved before the date that the financial statements are issued. Through March 31, 2017, the Company has funded its operations primarily with proceeds from sales of preferred and common shares and borrowings under a credit agreement. The Company has incurred recurring losses since its inception, including net losses of $18,753 and $2,986 during the three months ended March 31, 2017 and 2016, respectively. In addition, as of March 31, 2017, the Company had an accumulated deficit of $94,209. The Company expects to continue to generate operating losses for the foreseeable future. As of June 16, 2017, the issuance date of these consolidated financial statements, the Company expects that its cash of $52,286 as of March 31, 2017, together with the $176,367 of net cash proceeds received from the Company’s IPO, will be sufficient to fund its operating expenses, capital expenditure requirements and debt service payments for at least 15 months from the date of issuance of these consolidated financial statements, and as a result, there is not substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the financial statements are issued. The future viability of the Company beyond that point is dependent on its ability to raise additional capital to finance its operations. To execute its business plans, the Company will need substantial funding to support its continuing operations and pursue its growth strategy. Until such time as the Company can generate significant revenue from product sales, if ever, it expects to finance its operations through the sale of public or private equity, debt financings or other capital sources, including collaborations with other companies or other strategic transactions. The Company may not be able to obtain financing on acceptable terms, or at all. The terms of any financing may adversely affect the holdings or the rights of the Company’s shareholders. If the Company is unable to obtain funding, the Company could be forced to delay, reduce or eliminate some or all of its research and development programs, product portfolio expansion or commercialization efforts, which could adversely affect its business prospects.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2017
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of income and expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the accrual for research and development expenses and the valuation of common shares, stock options, warrants, derivative instruments and contingent equity instruments. In addition, management’s assessment of the Company’s ability to continue as a going concern involves the estimation of the amount and timing of future cash inflows and outflows. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates. Unaudited Interim Consolidated Financial Information The accompanying consolidated balance sheet as of March 31, 2017, the consolidated statements of operations and comprehensive loss and of cash flows for the three months ended March 31, 2017 and 2016, and the consolidated statement of convertible preferred shares and shareholders’ equity (deficit) as of March 31, 2017 are unaudited. The unaudited interim consolidated financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of March 31, 2017 and the results of its operations and its cash flows for the three months ended March 31, 2017 and 2016. The financial data and other information disclosed in these consolidated notes related to the three months ended March 31, 2017 and 2016 are unaudited. The results for the three months ended March 31, 2017 are not necessarily indicative of results to be expected for the year ending December 31, 2017, any other interim periods or any future year or period. Restricted Cash As of December 31, 2016, current restricted cash consisted of $67 of cash received from investors as an advance payment for their participation in the second closing of the Company’s sale of Series A preferred shares. The Company closed the second and final tranche of its Series A preferred financing in February 2017. As a result, there was no current restricted cash as of March 31, 2017. As of March 31, 2017 and December 31, 2016, the Company’s non-current restricted cash consisted of a $60 certificate of deposit held as a security deposit in connection with the Company’s corporate credit card. Deferred Offering Costs The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such equity financings are consummated. After consummation of the equity financing, these costs are recorded in shareholders’ equity (deficit) as a reduction of proceeds generated as a result of the offering. Should the planned equity financing be abandoned, the deferred offering costs will be expensed immediately as a charge to operating expenses in the consolidated statement of operations and comprehensive loss. As of March 31, 2017 and December 31, 2016, the Company recorded deferred offering costs relating to its IPO of $2,399 and $134, respectively. The Company’s IPO was completed in May 2017 and these costs were recorded as a reduction to shareholders’ equity. Equity Method Investments Investments in non-public companies in which the Company owns less than a 50% equity interest and where it exercises significant influence over the operating and financial policies of the investee are accounted for using the equity method of accounting. The Company’s proportionate share of the net income or loss of the equity method investment is included in other income (expense), net in the consolidated statement of operations and comprehensive loss and results in a corresponding adjustment to the carrying value of the investment on the consolidated balance sheet. Dividends received reduce the carrying value of the investment. The Company periodically reviews the carrying value of its investment to determine if there has been an other-than-temporary decline in carrying value. A variety of factors are considered when determining if a decline in carrying value is other than temporary, including, among other factors, the financial condition and business prospects of the investee as well as the Company’s intent with regard to the investment. Fair Value Measurements Certain assets of the Company are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: · Level 1— Quoted prices in active markets for identical assets or liabilities. · Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. · Level 3—Unobservable inputs that are supported by little or no market activity that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. The Company’s warrant liability, derivative liability and contingent equity liability are carried at fair value, determined according to the fair value hierarchy described above (see Note 3). The carrying values of other current assets, accounts payable, accrued expenses and notes payable under a credit agreement approximate their fair values due to the short-term nature of these assets and liabilities. Research and Development Costs Research and development costs are expensed as incurred. Research and development expenses consist of costs incurred in performing research and development activities, including salaries, share-based compensation and benefits, facilities costs, depreciation, third-party license fees, and external costs of outside vendors engaged to conduct clinical development activities and clinical trials as well as to manufacture clinical trial materials. Non-refundable prepayments for goods or services that will be used or rendered for future research and development activities are deferred and capitalized. Such amounts are recognized as an expense as the goods are delivered or the related services are performed, or until it is no longer expected that the goods will be delivered or the services rendered. Research Contract Costs and Accruals The Company has entered into various research and development-related contracts with companies both inside and outside of the United States. These agreements are cancelable, and related payments are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies or clinical trials, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical accrual estimates have not been materially different from the actual costs. Share-Based Compensation The Company measures stock options granted to employees and directors based on the fair value on the date of the grant and recognizes compensation expense of those awards, over the requisite service period, which is generally the vesting period of the respective award. Forfeitures are accounted for as they occur. Generally, the Company issues stock options with only service-based vesting conditions and records the expense for these awards using the straight-line method. The Company has not issued any stock options with performance-based vesting conditions. For share-based awards granted to consultants and non-employees, compensation expense is recognized over the period during which services are rendered by such consultants and non-employees until completed. At the end of each financial reporting period prior to completion of the service, the fair value of these awards is remeasured using the then-current fair value of the Company’s common shares and updated assumption inputs in the Black-Scholes option-pricing model. The Company classifies share-based compensation expense in its consolidated statement of operations and comprehensive loss in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified. The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model. Prior to May 2017, the Company was a private company and, accordingly, lacks company-specific historical and implied volatility information for its shares. Therefore, it estimates its expected share price volatility based on the historical volatility of publicly traded peer companies and expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded share price. The expected term of the Company’s stock options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The expected term of stock options granted to non-employees is equal to the contractual term of the option award. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that the Company has never paid cash dividends on common shares and does not expect to pay any cash dividends in the foreseeable future. Warrant Liability In connection with entering into a credit agreement (see Note 7), the Company agreed to issue warrants to purchase common shares to two of the Company’s directors in connection with a guarantee of its obligations under the agreement (see Note 7). The Company classifies the warrants as a liability on its consolidated balance sheet because each warrant represents a freestanding financial instrument that is not indexed to the Company’s own shares. The warrant liability was initially recorded at fair value upon entering into the credit agreement and is subsequently remeasured to fair value at each reporting date. Changes in the fair value of the warrant liability are recognized as a component of other income (expense), net in the consolidated statement of operations and comprehensive loss. Changes in the fair value of the warrant liability will continue to be recognized until the warrants are exercised, expire or qualify for equity classification. Derivative Liability The Company’s license agreement with Yale University (“Yale”) (see Note 12) provides for a change-of-control payment to Yale upon the occurrence of a change-of-control event, as defined in the agreement, including an IPO. The Company classifies the change-of-control payment obligation as a liability on its consolidated balance sheet because it represents a contingent obligation to pay a variable amount of cash that may be based, in part, on the value of the Company’s own shares. The derivative liability was initially recorded at fair value upon entering into the license agreement and is subsequently remeasured to fair value at each reporting date. Changes in the fair value of the derivative liability are recognized as a component of other income (expense), net in the consolidated statement of operations and comprehensive loss. In April 2017, the agreement with Yale was amended such that if the change-of-control event is an IPO, the change-of-control payment shall be due to Yale on the first trading day when Yale is free to sell its equity interest in the Company and the change-of-control fee shall be reduced by the dollar value of Yale’s equity interest in the Company on the first trading day when Yale is free to sell its equity interest in the Company. Yale’s equity interest in the Company is subject to a lock-up agreement, which generally restricts Yale’s shares from being traded until October 31, 2017 and accordingly, the amount due to Yale in connection with the change-of-control provision of the agreement, if any, will be determined upon expiration of the lock-up period. The Company will continue to remeasure the derivative liability to fair value at each reporting date and will recognize changes in the fair value of the derivative liability until the expiration of the lock-up agreement in October 2017 (see Note 17). Contingent Equity Liability The Company’s license agreements with AstraZeneca and BMS (see Note 12) require the Company to issue shares of capital stock upon the occurrence of specified financing or change-of-control events or development milestones, as defined in the agreements. In each agreement, the class and number of shares to be issued upon a triggering event were not known upon entering into the license agreements; however, the dollar amount of the shares to be issued upon a triggering event is fixed. The Company classifies these contingent obligations to issue shares as a liability on its consolidated balance sheet because each represents an obligation to issue a variable number of shares for a fixed dollar amount. Each contingent equity liability was initially recorded at fair value upon entering into each respective agreement and is subsequently remeasured to fair value at each reporting date. Changes in the fair values of the contingent equity liabilities are recognized as a component of other income (expense), net in the consolidated statement of operations and comprehensive loss. Changes in the fair value of the contingent equity liabilities will continue to be recognized until the occurrence of a respective triggering event. In May 2017, upon closing of the IPO, the conditions for issuing shares to BMS and AstraZeneca under the terms of the respective license agreements were satisfied, and accordingly, the Company issued 1,345,374 and 538,149 common shares, respectively, to BMS and AstraZeneca. The contingent equity liabilities were remeasured to fair value in the aggregate amount of $32,020 immediately prior to the completion of the IPO, and upon issuance of the common shares, the contingent equity liabilities were reclassified to shareholders’ equity (see Note 17). Net Loss per Share Attributable to Common Shareholders of Biohaven Pharmaceutical Holding Company Ltd. The Company follows the two-class method when computing net income (loss) per share as the Company has issued shares that meet the definition of participating securities. The two-class method determines net income (loss) per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires income available to common shareholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. Net income (loss) per share attributable to common shareholders is calculated based on net income (loss) attributable to Biohaven Pharmaceutical Holding Company Ltd. and excludes net income (loss) attributable to non-controlling interests for relevant periods. Basic net income (loss) per share attributable to common shareholders is computed by dividing the net income (loss) attributable to common shareholders by the weighted average number of common shares outstanding for the period. Diluted net income (loss) attributable to common shareholders is computed by adjusting net income (loss) attributable to common shareholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net income (loss) per share attributable to common shareholders is computed by dividing the diluted net income (loss) attributable to common shareholders by the weighted average number of common shares outstanding for the period, including potential dilutive common shares. For purpose of this calculation, outstanding options, warrants to purchase common shares, convertible preferred shares and contingently issuable equity are considered potential dilutive common shares. The Company’s convertible preferred shares contractually entitle the holders of such shares to participate in dividends but contractually do not require the holders of such shares to participate in losses of the Company. Accordingly, in periods in which the Company reports a net loss attributable to common shareholders, diluted net loss per share attributable to common shareholders is the same as basic net loss per share attributable to common shareholders, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. Recently Issued Accounting Pronouncements In January 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805) — Clarifying the Definition of a Business (“ASU 2017-01”). ASU 2017-01 finalizes previous proposals regarding shareholder concerns that the definition of a business is applied too broadly. The guidance assists entities with evaluating whether transactions should be accounted for as acquisitions of assets or of businesses. The amendments are effective for annual periods beginning after December 15, 2017, including interim periods within those periods. The Company is currently evaluating the impact that the adoption of ASU 2017-01 will have on its consolidated financial statements. In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfer of Assets Other than Inventory (“ASU 2016-16”), which requires the recognition of the income tax consequences of an intra-entity transfer of an asset, other than inventory, when the transfer occurs. The standard is effective for annual periods beginning after December 15, 2017, including interim periods within those fiscal years. The Company is currently evaluating the impact that the adoption of ASU 2016-16 will have on its consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments (“ASU 2016-15”), to address diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The standard is effective for annual periods beginning after December 15, 2017, including interim periods within those fiscal years. The Company is currently evaluating the impact that the adoption of ASU 2016-15 will have on its consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (“ASU 2016-02”), which sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e., lessees and lessors). The new standard requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee. This classification will determine whether lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease, respectively. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. Leases with a term of 12 months or less will be accounted for similar to existing guidance for operating leases today. ASU 2016-02 (Accounting Standards Codification (“ASC”) Topic 842) supersedes the previous leases standard, ASC 840, Leases . The standard is effective for public entities for annual periods beginning after December 15, 2018 and for interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the impact that the adoption of ASU 2016-02 will have on its consolidated financial statements. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”), which supersedes existing revenue recognition guidance under GAAP. The standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those goods or services. The standard defines a five-step process to achieve this principle, and will require companies to use more judgment and make more estimates than under the current guidance. The Company expects that these judgments and estimates will include identifying performance obligations in the customer contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. ASU 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date , which delays the effective date of ASU 2014-09 such that the standard is effective for public entities for annual periods beginning after December 15, 2017 and for interim periods within those fiscal years. Early adoption of the standard is permitted for annual periods beginning after December 15, 2016. In March 2016, the FASB issued ASU No. 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (“ASU 2016-08”), which further clarifies the implementation guidance on principal versus agent considerations in ASU 2014-09. In April 2016, the FASB issued ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing , clarifying the implementation guidance on identifying performance obligations and licensing. Specifically, the amendments in this update reduce the cost and complexity of identifying promised goods or services and improve the guidance for determining whether promises are separately identifiable. The amendments in this update also provide implementation guidance on determining whether an entity’s promise to grant a license provides a customer with either a right to use the entity’s intellectual property (which is satisfied at a point in time) or a right to access the entity’s intellectual property (which is satisfied over time). In May 2016, the FASB issued ASU No. 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients (“ASU 2016-12”), which clarifies the objective of the collectability criterion, presentation of taxes collected from customers, non-cash consideration, contract modifications at transition, completed contracts at transition and how guidance in ASU 2014-09 is retrospectively applied. ASU 2016-08, ASU 2016-10 and ASU 2016-12 have the same effective dates and transition requirements as ASU 2014-09. The Company is currently evaluating the impact that the adoption that these standards will have on its consolidated financial statements, if and when it generates revenue.

Fair Value of Financial Assets

Fair Value of Financial Assets and Liabilities	3 Months Ended
	Mar. 31, 2017
Fair Value of Financial Assets and Liabilities
Fair Value of Financial Assets and Liabilities	3. Fair Value of Financial Assets and Liabilities The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values: Fair Value Measurements as of March 31, 2017 Using: Level 1 Level 2 Level 3 Total Liabilities: Warrant liability $ — $ — $ $ Derivative liability — — Contingent equity liability — — $ — $ — $ $ Fair Value Measurements as of December 31, 2016 Using: Level 1 Level 2 Level 3 Total Liabilities: Warrant liability $ — $ — $ $ Derivative liability — — Contingent equity liability — — $ — $ — $ $ During the periods ended March 31, 2017 and December 31, 2016 there were no transfers between Level 1, Level 2 and Level 3. Valuation of Warrant Liability The warrant liability in the table above is composed of the fair value of warrants to purchase common shares that the Company agreed to issue to two of its directors in connection with a guarantee of its obligations under a credit agreement (see Note 7). The fair value of the warrant liability was determined based on significant inputs not observable in the market, which represents a Level 3 measurement within the fair value hierarchy. The Company utilized a Monte Carlo simulation, which is a statistical method used to generate a defined number of share price paths to develop a reasonable estimate of the range of the future expected share prices, to value the warrant liability. The Monte Carlo simulation incorporated assumptions and estimates to value the warrant liability. Estimates and assumptions impacting the fair value measurement included the estimated probability of adjusting the exercise price of the warrants, the number of shares for which the warrants will be exercisable, the fair value per share of the underlying common shares issuable upon exercise of the warrants, the remaining contractual term of the warrants, the risk-free interest rate, the expected dividend yield, and the expected volatility of the price of the underlying common shares. The Company estimated the fair value per share of its common shares by taking into consideration the most recent arm’s length sale of its common shares or third-party valuation of its common shares as well as additional factors that the Company deemed relevant. The Company historically has been a private company and lacks company-specific historical and implied volatility information of its shares. Therefore, it estimated its expected share volatility based on the historical volatility of publicly traded peer companies for a term equal to the remaining contractual term of the warrants. The risk-free interest rate was determined by reference to the U.S. Treasury yield curve for time periods approximately equal to the remaining contractual term of the warrants. The Company estimated a 0% expected dividend yield based on the fact that the Company has never paid or declared dividends and does not intend to do so in the foreseeable future. Valuation of Derivative Liability The fair value of the derivative liability recognized in connection with the Company’s license agreement with Yale (see Note 12) was determined based on significant inputs not observable in the market, which represents a Level 3 measurement within the fair value hierarchy. The fair value of the derivative liability was determined using the probability-weighted expected return method (“PWERM”), which considered as inputs the type and probability of occurrence of a change-of-control event, the amount of the payment, the expected timing of a change-of-control event and a risk-adjusted discount rate. In April 2017, the agreement with Yale was amended such that if the change-of-control event is an IPO, the change-of-control payment shall be due to Yale on the first trading day Yale is free to sell its equity interest in the Company and the change-of-control fee shall be reduced by the dollar value of Yale’s equity interest in the Company on the first trading day when Yale is free to sell its equity interest in the Company. Yale’s equity interest in the Company is subject to a lock-up agreement which generally restricts Yale’s shares from being traded until October 31, 2017, and accordingly, the amount due to Yale in connection with the change-of-control provision of the agreement, if any, will be determined upon expiration of the lock-up period in October 2017. Valuation of Contingent Equity Liability BMS. The fair value of the contingent equity liability recognized in connection with the Company’s license agreement with BMS (see Note 12) was determined based on significant inputs not observable in the market, which represents a Level 3 measurement within the fair value hierarchy. The fair value of the contingent equity liability was determined using the PWERM, which considered as inputs the probability of occurrence of events that would trigger the issuance of shares, the expected timing of such events, the value of the contingently issuable equity and a risk-adjusted discount rate. As of December 31, 2016, the assumed probability of occurrence of the event that was most probable of triggering the issuance of shares was 75%, the expected timing of such an event was estimated to be less than one year, the value of the contingently issuable equity was $18,750 and the discount rate was assessed to be 0%. As of March 31, 2017, the assumed probability of occurrence of the event that was most probable of triggering the issuance of shares was 85%, the expected timing of such an event was estimated to be less than one year, the value of the contingently issuable equity was $18,750 and the discount rate was assessed to be 0%. Based on these inputs, the Company determined that the fair value of the contingent equity liability was $14,063 as of December 31, 2016 and $15,938 as of March 31, 2017. AstraZeneca. The fair value of the contingent equity liability recognized in connection with the Company’s license agreement with AstraZeneca (see Note 12) was determined based on significant inputs not observable in the market, which represents a Level 3 measurement within the fair value hierarchy. The fair value of the contingent equity liability was determined using the PWERM, which considered as inputs the probability of occurrence of events that would trigger the issuance of shares, the expected timing of such events, the value of the contingently issuable equity and a risk-adjusted discount rate. The contingently issuable equity is issuable in two tranches, each for a fixed dollar amount of $5,000, for a total amount of $10,000. Using the PWERM, the Company assessed the fair value of each tranche of the contingent equity liability separately. In October 2016, upon completion of the Series A First Closing (see Note 9), the first tranche of contingently issuable equity became issuable to AstraZeneca. As a result, the Company issued to AstraZeneca 538,150 Series A preferred shares with an aggregate fair value of $5,000, or $9.2911 per share, in satisfaction of the obligation to issue the first tranche of equity under the agreement. Upon the issuance of the 538,150 Series A preferred shares to AstraZeneca in October 2016, the Company reclassified the carrying value of the first tranche contingent equity liability, equal to the then-current fair value of $5,000, to the carrying value of Series A preferred shares. The shares related to the second tranche become issuable upon the earlier of (i) the initiation of a Phase 2b or equivalent clinical trial of a product candidate based on the licensed patent rights and (ii) any liquidity event, including an IPO, any change of control or any assignment of the Company’s rights or obligations under the license agreement. As of December 31, 2016, the Company determined that the fair value of the second tranche contingent equity liability was $4,875. In determining this fair value, the assumed probability of occurrence of the event that was most probable of triggering the issuance of shares was 65%, the expected timing of such an event was estimated to be less than one year, the value of the contingently issuable equity was $7,500 and the discount rate was assessed to be 0%. As of March 31, 2017, the Company determined that the fair value of the second tranche contingent equity liability was $6,375. In determining this fair value, the assumed probability of occurrence of the event that was most probable of triggering the issuance of shares was 85%, the expected timing of such an event was estimated to be less than three months, the value of the contingently issuable equity was $7,500 and the discount rate was assessed to be 0%. The following table provides a roll forward of the aggregate fair values of the Company’s warrant liability, derivative liability and contingent equity liability, for which fair value is determined by Level 3 inputs: Warrant Derivative Contingent Liability Liability Equity Liability Balance at December 31, 2016 $ $ $ Change in fair value ) Balance at March 31, 2017 $ $ $ In connection with the closing of the IPO in May 2017, the conditions for issuing shares in connection with the contingent equity liabilities were satisfied, and accordingly, the Company issued 1,345,374 and 538,149 common shares, respectively, to BMS and AstraZeneca. The contingent equity liabilities were adjusted to fair value immediately prior to the completion of the IPO, and upon issuance of the common shares, the contingent equity liabilities were reclassified to equity (see Note 17). Beneficial Conversion Feature In connection with the second tranche closing of Series A preferred shares on February 17, 2017, the Company determined that the conversion option associated with the shares sold met the definition of a beneficial conversion feature (“BCF”) as the fair value of the underlying common shares exceeded the adjusted conversion price. The BCF was recognized at its fair value of $12,006 as a reduction to the carrying value of the Series A preferred shares and a corresponding adjustment to additional paid-in capital. The fair value was determined using Level 3 inputs, equal to the product of the number of shares sold in the second tranche closing multiplied by the difference between the adjusted conversion price and the per share value of common shares at the commitment date (see Note 9).

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	3 Months Ended
	Mar. 31, 2017
Prepaid Expenses and Other Current Assets
Prepaid Expenses and Other Current Assets	4. Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consisted of the following: March 31, December 31, 2017 2016 Prepaid clinical trial costs $ $ Other $ $

Equity Method Investment

Equity Method Investment	3 Months Ended
	Mar. 31, 2017
Equity Method Investment
Equity Method Investment	5. Equity Method Investment On August 29, 2016, the Company executed a stock purchase agreement with Kleo Pharmaceuticals, Inc. (“Kleo”), a privately held Delaware corporation, to purchase 3,000,000 shares of Kleo’s common stock at an initial closing, with a commitment to purchase an aggregate of 5,500,000 additional shares of common stock, in each case at a share price of $1.00 per share (the “Kleo SPA”). Kleo is a development-stage biopharmaceutical company focused on advancing the field of immunotherapy by developing small molecules that emulate biologics. Under the terms of the Kleo SPA, the Company purchased 3,000,000 shares upon the initial closing on August 31, 2016, and the remaining 5,500,000 shares are to be purchased in four equal tranches of 1,375,000 shares beginning six months from the initial closing and then every three months thereafter. In March 2017, the Company completed the first tranche purchase of 1,375,000 shares for cash consideration of $1,375. In connection with the Kleo SPA, the Company agreed to purchase an additional 500,000 shares of Kleo common stock from an officer and stockholder of Kleo. On March 30, 2017, the Company completed the purchase of these shares. The consideration paid for these shares consisted of a cash payment of $250 and the Company’s issuance of 32,500 common shares with a fair value of $10.82 per share on the date of issuance, or $352. The Company has a variable interest in Kleo through its equity investment. Kleo is a variable interest entity due to the equity investment at risk being insufficient to finance its activities. An assessment of whether or not the Company has the power to direct activities that most significantly impact Kleo’s economic performance and to identify the party that obtains the majority of the benefits of the investment was performed as of March 31, 2017 and December 31, 2016, and will be performed as of each subsequent reporting date. After each of these assessments, the Company concluded that the activities that most significantly impact Kleo’s economic performance are the ability to direct the research activities, the ability to select vendors to perform the research, the ability to maintain research staff and the ability to raise additional funds. Based on the outcome of these assessments, the Company concluded that consolidation of Kleo is not appropriate, and has therefore accounted for the investment under the equity method. The Company’s purchase of 3,000,000 shares of Kleo’s common stock during the year ended December 31, 2016 and the additional 1,875,000 shares of Kleo’s common stock during the three months ended March 31, 2017 represented an 18.6% and a 27.9% interest in the outstanding shares of Kleo as of December 31, 2016 and March 31, 2017, respectively. In connection with the initial investment, the Company also received the right to designate two of the five members of Kleo’s board of directors. The Company accounts for its investment in Kleo under the equity method of accounting. The Company has recorded its investments in Kleo to date based on the costs of those investments, as adjusted for the Company’s proportional share of Kleo’s net income or loss in each period. The difference between the cost of the Company’s investments in Kleo and its proportionate share of the net assets of Kleo was allocated to goodwill and indefinite-lived intangible assets. The Company will record future adjustments to the carrying value of its investment at each reporting date equal to its proportionate share of Kleo’s net income or loss for the corresponding period. The Company recorded other expense and a corresponding reduction in the carrying value of its investment in Kleo of $218 for its proportionate share of Kleo’s net loss for the three months ended March 31, 2017. The carrying value of the Company’s investment in Kleo was $4,511 and $2,753 as of March 31, 2017 and December 31, 2016, respectively, and is reported as equity method investment on the consolidated balance sheet. The carrying value of the investment represents the Company’s maximum loss exposure as of March 31, 2017. The following table provides a roll forward of the carrying value of the Company’s equity method investment: Carrying Value Balance at December 31, 2016 $ Purchases of Kleo common stock Loss recognized in connection with equity method investment ) Balance at March 31, 2017 $ Summarized financial information for Kleo was as follows: March 31, December 31, 2017 2016 Current assets $ $ Total assets $ $ Current liabilities $ $ Total liabilities $ $ Three Months Ended March 31, 2017 Revenue $ — Loss from Operations $ ) Net loss $ )

Accrued Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2017
Accrued Expenses
Accrued Expenses	6. Accrued Expenses Accrued expenses consisted of the following: March 31, December 31, 2017 2016 Accrued employee compensation and benefits $ $ Accrued clinical trial costs Accrued professional fees Accrued income taxes Other — $ $

Notes Payable

Notes Payable	3 Months Ended
	Mar. 31, 2017
Notes Payable
Notes Payable	7. Notes Payable Credit Agreement On August 30, 2016, the Company entered into a one-year credit agreement (the “Credit Agreement”) with Wells Fargo Bank, National Association (“Wells Fargo”) providing for a term loan in the principal amount of $5,000 (the “Loan”) and borrowed the full $5,000 available under the Credit Agreement. Borrowings under the Credit Agreement bear interest at a rate equal to monthly LIBOR plus 1.50% per annum, and the Credit Agreement requires monthly, interest-only payments beginning on September 30, 2016 and continuing through August 30, 2017 (the “Maturity Date”), when all amounts of unpaid principal and interest become due. The monthly LIBOR rate is reset each month (“LIBOR Period”). As of March 31, 2017, the interest rate applicable to the Loan was 2.48% per annum. In the event of a default, the interest rate applicable is equal to the monthly LIBOR rate then in effect, increased by 4.0% per annum. The Company’s obligations under the Credit Agreement are guaranteed by an outside director and shareholder of the Company (the “Guarantor”). A second outside director and shareholder of the Company entered into an agreement with the Guarantor under which the second director agreed to reimburse the Guarantor for one-half of any guaranty obligations that the Guarantor pays to Wells Fargo. The Credit Agreement also provides that the Company may voluntarily prepay the Loan at any time; however, if the Company elects to prepay the Loan or the Loan otherwise is accelerated and becomes payable prior to the Maturity Date, the Company will pay a prepayment premium, which will be the additional interest that would have accrued if the Loan remained outstanding through the end of the current monthly LIBOR Period. The Credit Agreement contains affirmative and negative covenants, but does not contain any financial covenants. There were no principal payments due or paid under the Credit Agreement during the three months ended March 31, 2017. In connection with entering into the Credit Agreement on August 30, 2016, the Company agreed to issue warrants to purchase $1,000 of common shares to each of the Guarantor and Co-Guarantor. The number of common shares issuable upon exercise of each warrant is determined by dividing $1,000 by the price per share paid by investors in the Series A First Closing (see Note 9). On January 26, 2017, the Company issued the warrants to the Guarantor and Co-Guarantor (see Note 8). The Company determined that the obligation to issue the warrants represented a liability that was considered outstanding for accounting purposes on August 30, 2016, the date of the Credit Agreement (see Note 8). The fair value of the warrant liability upon issuance represented a premium paid for the guaranty of the Loan, and, accordingly, the Company recorded the issuance-date fair value of the warrant liability of $934 as a debt discount and as a warrant liability in the Company’s consolidated balance sheet. In addition, the Company paid an arrangement fee of $150 to the lender and incurred legal costs of $47, both of which were recorded as a debt discount. The debt discount is reflected as a reduction of the carrying value of the notes payable on the Company’s consolidated balance sheet and is being amortized to interest expense over the term of the note using the effective interest method. The Company recognized interest expense of $298 during the three months ended March 31, 2017. The Company recognized $273 related to the accretion of the debt discount during the three months ended March 31, 2017. As of March 31, 2017, the unamortized debt discount was $511. Notes Payable to Related Parties On December 31, 2016, the Company entered into stock purchase agreements with each of the stockholders of BPI, acquiring 100% of the issued and outstanding shares of BPI for aggregate purchase consideration of $595. The Company funded the acquisition through the issuance of promissory notes to each of the former stockholders of BPI. The former stockholders of BPI are shareholders of the Company and also serve as the Company’s Chairman of the board of directors, Chief Executive Officer, and Chief Medical Officer, respectively. As of March 31, 2017, the notes were payable in five annual payments, the first four of which are interest only, with the final payment to include the principal balance outstanding plus any accrued and unpaid interest. The notes bear interest at a rate of 4.5% per annum and mature on December 31, 2021. The notes became immediately due and payable upon specified events, including immediately prior to the consummation of an initial public offering of the Company’s common shares or upon the occurrence of a change of control of the Company. There are no affirmative, negative or financial covenants associated with the notes. In connection with the closing of the Company’s IPO in May 2017, the notes were paid in full, including principal of $595, and accrued and unpaid interest of $9 (see Note 17).

Warrants

Warrants	3 Months Ended
	Mar. 31, 2017
Warrants
Warrants	8. Warrants ALS Biopharma Warrants On August 10, 2015, as partial consideration issued in connection with a license agreement with ALS Biopharma LLC (“ALS Biopharma”) (see Note 12), the Company issued to ALS Biopharma a warrant to purchase 275,000 common shares at an exercise price of $5.60 per share. The warrant was immediately exercisable upon issuance and expires 10 years from the issuance date. The warrant was classified as equity and recorded at its fair value on the date of issuance. On August 10, 2015, in connection with the same license agreement, the Company issued to ALS Biopharma a warrant to purchase 325,000 common shares at an exercise price of $5.60 per share. The warrant became exercisable upon the Company’s filing of an investigational new drug application (“IND”) for a patented product under the license agreement, and expires 10 years from the issuance date. On May 31, 2016, the Company filed an IND for a patented product under the license agreement. The warrant was classified as equity and recorded at its fair value on May 31, 2016. Guarantor and Co-Guarantor Warrants The Company agreed to issue warrants to purchase $1,000 of common shares to each of the Guarantor and Co-Guarantor of the Credit Agreement (see Note 7), who are members of the Company’s board of directors (see Note 15). The number of common shares issuable upon exercise of each warrant is determined by dividing $1,000 by the price per share paid by investors in the Series A First Closing (see Note 9). On January 26, 2017, the Company issued the warrants to the Guarantor and Co-Guarantor, pursuant to which each director received a warrant to purchase 107,500 common shares at an exercise price of $9.2911 per share. The warrants were immediately exercisable and expire upon the earlier to occur of (i) the fifth anniversary of the issuance date of the warrants and (ii) the second anniversary of the Company’s IPO. As of December 31, 2016, the Company determined that the obligation to issue the warrants represented a liability that was considered outstanding for accounting purposes on August 30, 2016, the date the Company entered into the Credit Agreement. The Company classified the warrants as a liability on its consolidated balance sheet because each warrant represents a freestanding financial instrument that is not indexed to the Company’s own shares. As of March 31, 2017, the Company continued to classify these warrants as a liability on the consolidated balance sheet because the warrants contain anti-dilution price protection provisions through January 26, 2018. As a result, changes in the fair value of the warrant liability will continue to be recognized as a component of other income (expense), net until the earliest of (i) the exercise of the warrants, (ii) the expiration of the warrants or (iii) January 26, 2018. The warrant liability was initially recorded at fair value upon entering into the Credit Agreement and is subsequently remeasured to fair value at each reporting date. Changes in the fair value of the warrant liability are recognized as a component of other income (expense), net in the Company’s consolidated statement of operations and comprehensive loss. The fair value of the warrant liability was determined to be $934 on the date of issuance. The Company remeasured the liability as of March 31, 2017 and December 31, 2016 and determined that the fair value of the warrant liability was $1,234 and $780, respectively. The Company recorded a gain of $454 recorded within other income (expense), net in the consolidated statements of operations for the three months ended March 31, 2017.

Convertible Preferred Shares

Convertible Preferred Shares	3 Months Ended
	Mar. 31, 2017
Convertible Preferred Shares
Convertible Preferred Shares	9. Convertible Preferred Shares As of March 31, 2017, the Company’s memorandum and articles of association, as amended and restated, authorized the Company to issue 11,242,172 Series A preferred shares. The holders of Series A preferred shares have liquidation rights in the event of a deemed liquidation that, in certain situations, is not solely within the control of the Company. Therefore, the Series A preferred shares are classified outside of shareholders’ equity (deficit). In October 2016, the Company issued and sold an aggregate of 4,305,209 Series A preferred shares, at an issuance price of $9.2911 per share, for proceeds of $37,295, net of offering costs of $2,705 (the “Series A First Closing”). The $2,705 of offering costs consisted of $1,730 payable in cash and 105,010 shares of the Company’s Series A preferred shares valued at $975, or $9.2911 per share, which were issued directly to the two placement agents involved in the Series A financing. The preferred share purchase agreement provided for the issuance of additional Series A preferred shares in a second and final tranche (the “Series A Second Closing”). Also, in October 2016, the Company issued to AstraZeneca 538,150 Series A preferred shares with an aggregate fair value of $5,000, or $9.2911 per share, in satisfaction of the obligation to issue the first tranche of contingently issuable equity under the Company’s license agreement with AstraZeneca (see Note 12). In February 2017, the Company completed the Series A Second Closing through the issuance and sale of an aggregate of 4,305,182 Series A preferred shares at an issuance price of $9.2911 per share for cash proceeds of $38,636, net of offering costs of $2,606. The $2,606 of offering costs for the second tranche consisted of $1,364 payable in cash and 105,009 shares of the Company’s Series A preferred shares valued at $1,242, or $11.83 per share, which were issued directly to the two placement agents involved in the Series A financing. The conversion option associated with the Series A preferred shares sold in the second closing met the definition of a BCF as the fair value of the underlying common shares of $9.85 per share exceeded the stated conversion price of $9.2911 (or $7.0613, as adjusted, as described below under Conversion). Upon the sale and issuance of the Series A preferred shares, $2,406 of the BCF was immediately accreted, as this represented the difference between the stated conversion price and per share value of the common shares. The remaining portion of the BCF is being amortized using the effective interest method over the period from the date of issuance to the date of the earliest possible conversion, October 1, 2017. For the three months ended March 31, 2017, the Company recorded accretion of the BCF of $4,000. In May 2017, upon the completion of the Company’s IPO, all of the outstanding Series A preferred shares were automatically converted into an aggregate of 9,358,560 common shares pursuant to the related agreements (see Note 17). Upon conversion of the Series A preferred shares, the remaining unamortized BCF was reclassified to additional paid-in capital as a deemed dividend (see Note 17). The holders of the Series A preferred shares had the following rights and preferences prior to the conversion to common shares: Voting The holders of Series A preferred shares were entitled to vote, together with the holders of common shares, on all matters submitted to shareholders for a vote. The holders of Series A preferred shares were entitled to the number of votes equal to the number of common shares into which their Series A preferred shares could convert. Conversion Each Series A preferred share was convertible into common shares at the option of the shareholder at any time after the date of issuance. In addition, pursuant to the Company’s memorandum and articles of association, as amended and restated, each Series A preferred share would be automatically converted into common shares, at the applicable conversion ratio then in effect, upon the earlier of (i) a firm commitment public offering with proceeds to the Company of at least $50,000, before deducting underwriting discounts and commissions or (ii) the date specified by the vote or written consent of the holders of a majority of the then outstanding Series A preferred shares. The conversion ratio of Series A preferred shares was determined by dividing the Original Issue Price by the Conversion Price. The Original Issue Price of the Series A preferred shares was $9.2911 per share. The Conversion Price of the Series A preferred shares was $9.2911 per share, subject to appropriate adjustment in the event of any stock split, stock dividend, combination or other similar recapitalization and other adjustments as set forth in the Company’s memorandum and articles of association, as amended and restated. On the date of issuance, each Series A preferred share was convertible into one common share. In the event that any Series A preferred share investor did not participate in the second and final tranche of the Series A preferred financing, that investor’s shares would have been convertible into common shares at a ratio of one common share for every 1,000 Series A preferred shares. In addition, if the Company decided not to move forward with a Phase 3 clinical trial on its product candidate, rimegepant, or if the Company failed to initiate a Phase 3 clinical trial prior to October 1, 2017, the Conversion Price of the Series A preferred shares would have been reduced to $7.0613 per share. Dividends The holders of Series A preferred shares were entitled to receive dividends in preference to any dividend on common shares at the rate of 8.0% per year of the Original Issue Price. Dividends accrued daily and compounded annually, whether or not declared, would be payable when, as and if declared by the board or directors of the Company and were noncumulative. The Company was not permitted to declare, pay or set aside any dividends on shares of any other class or series of capital stock of the Company unless the holders of Series A preferred shares then outstanding first received, or simultaneously received, dividends on each outstanding Series A preferred share. Accruing dividends, whether or not declared, were payable upon any liquidation event. Declared but unpaid dividends would have been payable upon the conversion of the Series A preferred shares into common shares. Liquidation In the event of any voluntary or involuntary liquidation, dissolution or winding-up of the Company or a Deemed Liquidation Event (as described below), the holders of Series A preferred shares then outstanding were entitled to receive, in preference to holders of common shares, an amount equal to the greater of (i) the Original Issue Price per share, plus all dividends declared but unpaid on such shares or (ii) the amount such holders would have received had all of their Series A preferred shares been converted into common shares immediately prior to such liquidation event. If upon any such liquidation event, the assets of the Company available for distribution were insufficient to permit payment in full to the holders of Series A preferred shares, the proceeds would be ratably distributed among the holders of Series A preferred shares in proportion to the respective amounts that they would have received if they were paid in full. After payments have been made in full to the holders of Series A preferred shares, the remaining assets of the Company available for distribution would be distributed among the holders of common shares ratably in proportion to the number of shares held by each such holder. Unless a majority of the holders of the then outstanding Series A preferred shares elected otherwise, a Deemed Liquidation Event would include a merger or consolidation (other than one in which shareholders of the Company own a majority by voting power of the outstanding shares of the surviving or acquiring corporation) or a sale, lease, transfer, exclusive license or other disposition of all or substantially all of the assets of the Company. Redemption The Company’s memorandum and articles of association, as amended and restated, did not provide redemption rights to the holders of Series A preferred shares.

Common Shares

Common Shares	3 Months Ended
	Mar. 31, 2017
Common Shares
Common Shares	10. Common Shares As of December 31, 2016 and March 31, 2017, the Company’s memorandum and articles of association, as amended and restated, authorized the Company to issue 38,000,000 no par value common shares. Each common share entitles the holder to one vote on all matters submitted to a vote of the Company’s shareholders. Common shareholders are entitled to receive dividends, as may be declared by the board of directors, if any. Through March 31, 2017, no dividends had been declared. In February 2016, the Company issued 429,000 common shares at an issuance price of $7.00 per share for proceeds of $2,980, net of issuance costs of $23. In May 2016 and July 2016, the Company issued an aggregate of 1,090,500 common shares at an issuance price of $7.70 per share for proceeds of $8,299, net of issuance costs of $97. In July 2016, concurrently with the issuance of the Company’s common shares to Connecticut Innovations Incorporated (“CII”), the Company and CII entered into a put agreement (the “Put Agreement”). The Put Agreement grants CII the right to sell (the “Put Option”) to the Company all or any part of CII’s warrant rights (if any), shares (if any) or notes (if any). The Put Option becomes exercisable upon the Company’s breach of the covenant to maintain a presence in Connecticut, as defined in the Put Agreement. Upon CII’s exercise of the Put Option, the Company would be obligated to purchase CII’s shares for a price that is the greater of (i) the current market price of such share and (ii) the original purchase price of such share. The right to put the shares will terminate at such time that the shares may be sold (i) pursuant to an effective registration statement under the Securities Act of 1933 (the “Securities Act”), (ii) pursuant to Rule 144 promulgated under the Securities Act, but in each case, only after the termination of any applicable “lock-up” restrictions and, in the case of (ii), only if the common shares are then listed for trading on a national securities exchange. The fair value of the Put Option was determined to be $0 upon execution of the Put Agreement and as of March 31, 2017 because the ability to maintain a presence in Connecticut is within the Company’s control. In April 2017, the Company effected an increase in the number of authorized common shares from 38,000,000 shares to 50,000,000 shares (see Note 17). On May 3, 2017, the Company’s registration statement on Form S-1 relating to the IPO was declared effective by the SEC. The IPO closed on May 9, 2017 and the Company issued and sold 9,900,000 common shares at a public offering price of $17.00 per share for net proceeds of $152,889 after deducting underwriting discounts and commissions of $11,781 and other offering expenses of approximately $3,630. Upon the closing of the IPO, all convertible preferred shares then outstanding converted into an aggregate of 9,358,560 common shares. In addition, on May 9, 2017, the underwriters of the IPO fully exercised their option to purchase additional shares, and on May 11, 2017, the Company issued and sold 1,485,000 additional common shares for additional net proceeds of $23,478 after deducting underwriting discounts and commissions of $1,767. Thus, the aggregate net proceeds to the Company from the IPO, after deducting underwriting discounts and commissions and offering expenses, were $176,367. In connection with the completion of its IPO, the Company issued an additional aggregate of 1,883,523 common shares to BMS and AstraZeneca in satisfaction of obligations to contingently issue equity securities pursuant to the license agreements (see Note 12), for no additional consideration. Also in connection with the completion of its IPO in May 2017, the Company amended its memorandum and articles of association to authorize the issuance of up to 200,000,000 no par value common shares and 10,000,000 no par value undesignated preferred shares.

Share-Based Compensation

Share-Based Compensation	3 Months Ended
	Mar. 31, 2017
Share-Based Compensation
Share-Based Compensation	11. Share-Based Compensation 2014 Equity Incentive Plan The Company’s 2014 Equity Incentive Plan, as amended, (the “2014 Plan”) provides for the Company to sell or issue common shares or restricted common shares, or to grant incentive stock options or nonqualified stock options for the purchase of common shares, to employees, members of the board of directors and consultants of the Company. The 2014 Plan is administered by the board of directors, or at the discretion of the board of directors, by a committee of the board. The exercise prices, vesting and other restrictions are determined at the discretion of the board of directors, or their committee if so delegated, except that the exercise price per share of stock options may not be less than 100% of the fair market value of the common share on the date of grant and the term of stock option may not be greater than ten years. The total number of common shares that may be issued under the 2014 Plan was 4,000,000 shares as of December 31, 2016. In January 2017, the Company effected an increase, effective October 28, 2016, in the number of common shares reserved for issuance under the 2014 Plan from 4,000,000 to 4,899,230 shares. The total number of common shares that may be issued under the 2014 Plan was 4,899,230 shares as of March 31, 2017. As of March 31, 2017 and December 31, 2016, 553,886 and 1,034,805 shares remained available for future grant under the 2014 Plan, respectively. Vesting periods are determined at the discretion of the board of directors. Stock options granted to employees and directors typically vest over three years. Stock options granted to non-employees typically vest over three years. The Company measures and records the value of these options over the period of time services are provided and, as such, unvested portions are subject to remeasurement at subsequent reporting periods. During the three months ended March 31, 2017, the Company granted options to purchase 422,382 common shares to employees and directors, and there were no options granted during the three months ended March 31, 2016. The Company recorded share-based compensation expense for options granted to employees and directors of $1,153 and $432 during the three months ended March 31, 2017 and 2016, respectively. During the three months ended March 31, 2017, the Company granted options to purchase 58,537 common shares to non-employees, and there were no options granted during the three months ended March 31, 2016. The Company recorded share-based compensation expense for options granted to non-employees of $733 and $255 during the three months ended March 31, 2017 and 2016, respectively. In May 2017, the Company’s shareholders approved the 2017 Equity Incentive Plan (the “2017 Plan”). The 2017 Plan became effective on May 3, 2017 in connection with the Company’s IPO. Upon the effectiveness of the 2017 Plan, no further grants will be made under the 2014 Plan (see Note 17). Stock Option Valuation The assumptions that the Company used to determine the grant-date fair value of stock options granted to employees and directors under the 2014 Plan during the three months ended March 31, 2017 were as follows, presented on a weighted average basis, noting there were no stock options granted to employees and directors during the three months ended March 31, 2016: Three Months Ended Risk-free interest rate % Expected term (in years) Expected volatility % Expected dividend yield % Exercise price $ Fair value of common share $ The assumptions that the Company used to determine the grant-date fair value of stock options granted to non-employees under the 2014 Plan during the three months ended March 31, 2017 were as follows, presented on a weighted average basis, noting there were no stock options granted to non-employees during the three months ended March 31, 2016: Three Months Ended Risk-free interest rate % Expected term (in years) Expected volatility % Expected dividend yield % Exercise price $ Fair value of common share $ Stock Options Stock option activity under the 2014 Plan is summarized as follows: Weighted Weighted Average Average Remaining Aggregate Number of Exercise Contractual Intrinsic Shares Price Term Value (in years) Outstanding as of December 31, 2016 $ $ Granted Exercised — — Forfeited — — Outstanding as of March 31, 2017 $ $ $ Options exercisable as of March 31, 2017 $ $ $ Options unvested as of March 31, 2017 $ $ $ The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common shares for those stock options that had exercise prices lower than the fair value of the Company’s common shares. There have been no exercises as of March 31, 2017. The weighted average grant-date fair value per share of stock options granted for the three months ended March 31, 2017 was $5.57. There were no stock options granted during the three months ended March 31, 2016. The total fair value of options vested for the three months ended March 31, 2017 and 2016 was $1,034 and $0, respectively. Share-Based Compensation Share-based compensation expense was classified in the consolidated statements of operations and comprehensive loss as follows: Three Months Ended March 31, 2017 2016 Research and development expenses $ $ General and administrative expenses $ $ As of March 31, 2017, total unrecognized compensation cost related to the unvested share-based awards was $7,685, which is expected to be recognized over a weighted average period of 2.01 years. 2017 Employee Share Purchase Plan In May 2017, the Company’s shareholders approved the 2017 Employee Share Purchase Plan (the “2017 ESPP”). The 2017 ESPP became effective on May 3, 2017 in connection with the Company’s IPO (see Note 17).

License Agreements

License Agreements	3 Months Ended
	Mar. 31, 2017
License Agreements
License Agreements	12. License Agreements Yale Agreement In September 2013, the Company entered into an exclusive license agreement with Yale (the “Yale Agreement”) to obtain a license to certain patent rights for the commercial development, manufacture, distribution, use and sale of products and processes resulting from the development of those patent rights, related to the use of riluzole in treating various neurological conditions, such as general anxiety disorder, post-traumatic stress disorder and depression. As part of the consideration for this license, the Company issued Yale 250,000 common shares and granted Yale the right to purchase up to 10% of the securities issued in specified future equity offerings by the Company. In the event that Yale’s fully diluted ownership position following the closing of the Company’s first two financings with institutional investors resulting in an investment of at least $3,500 fell below 1% of the Company’s fully diluted common shares outstanding, the Company would be required to issue to Yale an additional number of shares of common shares such that Yale’s ownership position is restored to no less than 1%. The obligation to contingently issue equity to Yale was determined to be a liability, which was accounted for at fair value and remeasured at each reporting date. The fair value of the obligation at inception of the Yale Agreement was $0 based on the Company’s assessment that the probability of issuing additional shares that would reduce Yale’s ownership percentage below 1% was remote. The fair value of the liability remained at $0 through the completion of the Company’s common share issuances in January 2014 and July 2015, at which time the contingent obligation terminated, as Yale’s ownership position remained above 1%. The Yale Agreement provides for a change-of-control payment to Yale upon the occurrence of a change-of-control event, as defined in the agreement, including an IPO. Upon the occurrence of a change-of-control event, the Company is obligated to pay to Yale the lesser of (i) 5% of the dollar value of all initial and future potential consideration paid or payable by the acquirer and (ii) $1,500. If the change-of-control event is as an IPO, the amount the Company will be obligated to pay to Yale will be reduced by the value of Yale’s equity investment in the Company on the first day that Yale is free to sell its equity interest. The Company classifies the change-of-control payment obligation as a liability on its consolidated balance sheet because it represents a contingent obligation to pay a variable amount of cash that may be based, in part, on the value of the Company’s own shares. The issuance-date fair value of the derivative liability was recognized as research and development expense in the consolidated statement of operations and comprehensive loss upon entering into the agreement with Yale. The derivative liability is remeasured to fair value at each reporting date. Changes in the fair value of the derivative liability are recognized as a component of other income (expense), net in the consolidated statement of operations and comprehensive loss. In April 2017, the agreement with Yale was amended such that if the change-of-control event is an IPO, the change-of-control payment shall be due to Yale on the first trading day when Yale is free to sell its equity interest in the Company and the change-of-control fee shall be reduced by the dollar value of Yale’s equity interest in the Company on the first trading day when Yale is free to sell its equity interest in the Company. Yale’s equity interest in the Company is subject to a lock-up agreement which generally restricts Yale’s shares from being traded until October 31, 2017, and accordingly, the amount due to Yale in connection with the change-of-control provision of the agreement, if any, will be determined upon expiration of the lock-up period. The Company will continue to remeasure the derivative liability to fair value at each reporting date and will recognize changes in the fair value of the derivative liability until the expiration of the lock-up in October 2017 (see Note 17). During the three months ended March 31, 2017 and 2016, the Company recorded other expense of $289 and $3, respectively, for the change in the fair value of the derivative liability. The fair value of the derivative liability was $223 and $512 as of March 31, 2017 and December 31, 2016, respectively. In addition, the Company agreed to pay Yale up to $2,000 upon the achievement of specified regulatory milestones and annual royalty payments of a low single-digit percentage based on net sales of products from the licensed patents, subject to a minimum amount of up to $1,000 per year. If the Company grants any sublicense rights under the Yale Agreement, it must pay Yale a low single-digit percentage of sublicense income that it receives. The Yale Agreement also requires the Company to meet certain due diligence requirements based upon specified milestones. The Company can elect to extend the deadline for its compliance with the due diligence requirements by a maximum of one year upon the payment to Yale of up to $150. The Company is also required to reimburse Yale for any fees that Yale incurs related to the filing, prosecution, defending and maintenance of patent rights licensed under the Yale Agreement. In the event that the Company fails to make any payments, commits a material breach, fails to maintain adequate insurance or challenges the patent rights of Yale, Yale can terminate the Yale Agreement. The Company can terminate the Yale Agreement (i) upon 90 days’ notice to Yale, (ii) if Yale commits a material breach of the Yale Agreement or (iii) as to a specific country if there are no valid patent rights in such country. The Yale Agreement expires on a country-by-country basis upon the later of the date on which the last patent rights expire in such country or ten years from the date of the first sale of a product incorporating the licensed patents. The Company recorded research and development expenses of $3 during the three months ended March 31, 2017, for reimbursement of patent fees in connection with the Yale Agreement. MGH Agreement In September 2014, the Company entered into a license agreement (the “MGH Agreement”) with The General Hospital Corporation d/b/a Massachusetts General Hospital (“MGH”), pursuant to which MGH granted the Company a license to certain patent rights for the commercial development, manufacture, distribution and use of any products or processes resulting from development of those patent rights, related to treating depression with a combination of ketamine and scopolamine. The Company is also obligated to pay MGH annual license maintenance fees of between $30 and $50, beginning in 2017, future milestone payments of up to $750 upon the achievement of specified clinical and regulatory milestones and up to $2,500 upon the achievement of specified commercial milestones. The Company has also agreed to pay MGH royalties of a low single-digit percentage based on net sales of products licensed under the agreement. If the Company receives revenue from sublicensing any of its rights under the agreement, the Company is also obligated to pay a portion of that revenue to MGH. The MGH Agreement also requires the Company to meet certain due diligence requirements based upon specified milestones. The Company can elect to extend the deadline for its compliance with the due diligence requirements by a maximum of one year by making payments to MGH of up to $300 in the aggregate. The Company is required to reimburse MGH for any fees that MGH incurs related to the filing, prosecution, defending, and maintenance of patent rights licensed under the agreement. The MGH Agreement expires upon expiration of the patent rights under the MGH Agreement, unless earlier terminated by either party. The Company did not recognize any research and development expense associated with the MGH Agreement during the three months ended March 31, 2017 and 2016. ALS Biopharma Agreement In August 2015, the Company entered into an agreement (the “ALS Biopharma Agreement”) with ALS Biopharma and Fox Chase Chemical Diversity Center Inc. (“FCCDC”), pursuant to which ALS Biopharma and FCCDC assigned the Company their worldwide patent rights to a family of over 300 prodrugs of glutamate modulating agents, including trigriluzole, as well as other innovative technologies. Under the ALS Biopharma Agreement, the Company is obligated to use commercially reasonable efforts to commercialize and develop markets for the patent products. The Company is obligated to pay $3,000 upon the achievement of specified regulatory milestones with respect to the first licensed product and $1,000 upon the achievement of specified regulatory milestones with respect to subsequently developed products, as well as royalty payments of a low single-digit percentage based on net sales of products licensed under the agreement, payable on a quarterly basis. In connection with the ALS Biopharma Agreement, the Company also issued to ALS Biopharma (i) 50,000 common shares; (ii) an immediately exercisable warrant to purchase 275,000 common shares at an exercise price of $5.60 per share; and (iii) a warrant to purchase 325,000 common shares at an exercise price of $5.60 per share, which warrant would become exercisable upon the Company’s achievement of a specified regulatory milestone (see Note 8). The ALS Biopharma Agreement terminates on a country-by-country basis as the last patent rights expire in each such country. If the Company abandons its development, research, licensing or sale of all products covered by one or more claims of any patent or patent application assigned under the ALS Biopharma Agreement, or if the Company ceases operations, it has agreed to reassign the applicable patent rights back to ALS Biopharma. The Company recorded research and development expenses of $0 and $375 during the three months ended March 31, 2017 and 2016, respectively, as a result of the ALS Biopharma Agreement, which amounts consist of the fair value of the shares and warrants upon their issuance to ALS Biopharma. Rutgers Agreement In June 2016, the Company entered into an exclusive license agreement (the “Rutgers Agreement”) with Rutgers, The State University of New Jersey (“Rutgers”), licensing several patents and patent applications related to the use of riluzole to treat various cancers. Under the Rutgers Agreement, the Company is required to pay Rutgers annual license maintenance fees in the aggregate of $75 for the first five years following execution of the agreement, then $25 per year thereafter until the first commercial sale of a licensed product, at which point the Company will pay Rutgers minimum annual royalties totaling in the low six-digits. The Company is also obligated to pay Rutgers up to $825 in the aggregate upon the achievement of specified clinical and regulatory milestones. The Company also agreed to pay Rutgers royalties of a low single-digit percentage of net sales of licensed products sold by the Company, its affiliates or its sublicensees, subject to a minimum amount of up to $100 per year. If the Company grants any sublicense rights under the Rutgers Agreement, the Company must pay Rutgers a low double-digit percentage of sublicense income it receives. Under the Rutgers Agreement, in the event that the Company experiences a change of control or sale of substantially all of its assets prior to the initiation of a Phase 3 clinical trial related to products licensed under the agreement, and such change of control or sale results in a full liquidation of the Company, the Company will be obligated to pay Rutgers a change-of-control fee equal to 0.3% of the total value of the transaction, but not less than $100. The Company determined that the change-of-control payment should be accounted for as a liability because it represents a contingent obligation to pay a variable amount of cash that may be based, in part, on the value of the Company’s own shares. The fair value of the obligation upon execution of the Rutgers Agreement was $0 based on the Company’s assessment that the probability of a change-in-control event occurring prior to the initiation of a Phase 3 clinical trial related to products licensed under the agreement was remote. The fair value of the liability remained at $0 through March 31, 2017. The Rutgers Agreement also requires the Company to meet certain due diligence requirements based upon specified milestones. The Company can elect to extend the deadline for its compliance with the due diligence requirements by a maximum of one year upon payments to Rutgers of up to $500 in the aggregate. Under the Rutgers Agreement, the Company is required to reimburse Rutgers for any fees that Rutgers incurs related to the filing, prosecution, defending, and maintenance of patent rights licensed under the agreement. The Rutgers Agreement expires upon expiration of the patent rights under the agreement or ten years from the date of first commercial sale of a licensed product, whichever is later, unless terminated by either party. The Company recorded no research and development expense during the three months ended March 31, 2017 related to the Rutgers Agreement. BMS Agreement In July 2016, the Company entered into an exclusive, worldwide license agreement (the “BMS Agreement”) with BMS for the development and commercialization rights to rimegepant and BHV-3500, as well as other CGRP-related intellectual property. In exchange for these rights, the Company agreed to pay BMS initial payments, milestone payments and royalties on net sales of licensed products under the agreement. The Company is obligated to make milestone payments to BMS upon the achievement of specified development and commercialization milestones. The development milestone payments due under the agreement depend on the licensed product being developed. With respect to rimegepant, the Company is obligated to pay up to $127,500 in the aggregate upon the achievement of the development milestones. For any product other than rimegepant, the Company is obligated to pay up to $74,500 in the aggregate upon the achievement of the development milestones. In addition, the Company is obligated to pay up to $150,000 for each licensed product upon the achievement of commercial milestones. If the Company receives revenue from sublicensing any of its rights under the agreement, it is also obligated to pay a portion of that revenue to BMS. The Company is also obligated to make tiered royalty payments to BMS based on annual worldwide net sales, with percentages in the low to mid teens. Under the BMS Agreement, the Company is obligated to use commercially reasonable efforts to develop licensed products and to commercialize at least one licensed product using the patent rights licensed from BMS and is solely responsible for all development, regulatory and commercial activities and costs. The Company is also required to reimburse BMS for any fees that BMS incurs related to the filing, prosecution, defending, and maintenance of patent rights licensed under the BMS Agreement. Under the BMS Agreement, BMS transferred to the Company manufactured licensed products, including certain materials that will be used by the Company to conduct clinical trials. The BMS Agreement will terminate on a licensed product-by-licensed product and country-by-country basis upon the expiration of the royalty term with respect to each licensed product in each country. BMS has the right to terminate the agreement upon the Company’s insolvency or bankruptcy, the Company’s uncured material breach of the agreement, including the failure to meet its development and commercialization obligations, or if the Company challenges any of BMS’s patent rights. The Company has the right to terminate the BMS Agreement if BMS materially breaches the agreement or if, after the Company provides notice, it chooses not to move forward with development and commercialization in a specific country. The BMS Agreement required the Company to complete a financing transaction with gross proceeds of at least $30,000, of which a minimum of $22,000 was to be from investment in equity prior to October 17, 2016, unless extended by mutual agreement of the Company and BMS. The BMS Agreement was amended, effective October 14, 2016, to extend the deadline for completing the financing transaction to October 31, 2016, on which date the Series A First Closing was completed (see Note 9). Under the BMS Agreement, the Company also agreed to issue BMS common shares in the amount of $12,500, which shares are contingently issuable upon the earliest to occur of (i) the initiation of a Phase 3 trial for the first licensed compound to reach such milestone, (ii) the Company’s IPO or (iii) an event resulting in the change of control of the Company. Under the terms of the BMS Agreement, if the qualifying financing transaction involves the issuance of preferred shares, BMS is entitled to receive preferred shares instead of common shares, at its option. BMS also had the right to purchase up to 8%, on a fully diluted basis, of shares issued in a qualifying financing transaction (as defined in the BMS Agreement) on the same terms and rights as all other investors involved in the financing. The number of shares issuable to BMS under the agreement will be determined by dividing $12,500 by a price per share equal to the lower of (i) the price per share paid by investors in the Series A First Closing, or $9.2911 (see Note 9), or (ii) the price per share paid by investors in any subsequent financing event that occurs prior to the events specified above. The obligation to contingently issue equity to BMS is classified as a liability on the consolidated balance sheet because it represents an obligation to issue a variable number of shares for a fixed dollar amount. Upon entering into the BMS Agreement, the issuance-date fair value of the contingent equity liability was recognized as research and development expense in the consolidated statement of operations and comprehensive loss. The Company remeasured the fair value of the contingent equity liability as of March 31, 2017 and recognized expense of $1,875 for the increase in the fair value of the liability to $15,938. Changes in the fair value of the contingent equity liability are recognized as a component of other income (expense), net in the consolidated statement of operations and comprehensive loss. Changes in the fair value of the contingent equity liability continued to be recognized until the occurrence of a triggering event, which occurred in May 2017 with the completion of the IPO. In May 2017, in connection with the completion of its IPO, the Company issued 1,345,374 common shares to BMS in satisfaction of its obligation to contingently issue equity securities pursuant to the license agreement (see Note 17) and remeasured the contingent equity liability to fair value. The Company recorded no research and development expense related to the BMS Agreement during the three months ended March 31, 2017. AstraZeneca Agreement In October 2016, the Company entered into an exclusive license agreement (the “AstraZeneca Agreement”) with AstraZeneca, pursuant to which AstraZeneca granted the Company a license to certain patent rights for the commercial development, manufacture, distribution and use of any products or processes resulting from development of those patent rights, including BHV-5000 and BHV-5500. In exchange for these rights, the Company agreed to pay AstraZeneca an upfront payment, milestone payments and royalties on net sales of licensed products under the agreement. The regulatory milestones due under the agreement depend on the indication of the licensed product being developed as well as the territory where regulatory approval is obtained. Development milestones due under the agreement with respect to Rett syndrome total up to $30,000, and, for any indication other than Rett syndrome, total up to $60,000. Commercial milestones are based on net sales of all products licensed under the agreement and total up to $120,000. The Company has also agreed to pay tiered royalties based on net sales of all products licensed under the agreement of mid single-digit to low double-digit percentages. If the Company receives revenue from sublicensing any of its rights under the AstraZeneca Agreement, the Company is also obligated to pay a portion of that revenue to AstraZeneca. The Company is also required to reimburse AstraZeneca for any fees that AstraZeneca incurs related to the filing, prosecution, defending, and maintenance of patent rights licensed under the AstraZeneca Agreement. The AstraZeneca Agreement expires upon the expiration of the patent rights under the agreement, unless earlier terminated by either party, or on a country-by-country basis ten years after the first commercial sale. As part of the consideration under the AstraZeneca Agreement, the Company agreed to issue to AstraZeneca common shares in the amount of $10,000 if the Company completed a qualifying equity financing resulting in proceeds of at least $30,000 prior to December 29, 2016. Under the terms of the AstraZeneca Agreement, if the qualifying financing transaction involved the issuance of preferred shares, AstraZeneca would be entitled to receive preferred shares instead of common shares, at its option. The number of shares issued would be determined based on the price per share paid by investors in the qualifying financing transaction. Upon the occurrence of the qualifying financing transaction, 50% of the shares would be issuable upon the closing of the transaction (the “First Tranche”) and the other 50% would become issuable upon the earlier of (i) the initiation of a Phase 2b or equivalent clinical trial of a product candidate based on the licensed patent rights or (ii) any liquidity event, including an IPO of the Company, any change of control of the Company or any assignment of the Company’s rights and obligations under the AstraZeneca Agreement (the “Second Tranche”). The number of shares issuable to AstraZeneca in each of the First Tranche and the Second Tranche is determined by dividing $5,000 by the price per share paid by investors in the Company’s Series A First Closing, or $9.2911 (see Note 9). In addition, AstraZeneca had the right to purchase up to 8%, on a fully diluted basis, of shares issued in such qualifying financing transaction, on the same terms and rights as all other investors involved in the financing. In October 2016, upon completion of the Series A First Closing (see Note 9), the contingency associated with the First Tranche of contingently issuable equity related to the occurrence of a qualified financing was satisfied. As a result, the Company issued to AstraZeneca 538,150 Series A preferred shares with an aggregate fair value of $5,000, or $9.2911 per share. Upon issuance of the 538,150 Series A preferred shares to AstraZeneca, the Company reclassified the contingent equity liability associated with the First Tranche of $5,000 to the carrying value of Series A preferred shares. As of March 31, 2017, the Company determined that the fair value of the contingent equity liability associated with the Second Tranche was $6,375, which resulted in the recognition of other expense of $1,500 during the three months ended March 31, 2017. Changes in the fair value of the contingent equity liability is recognized as a component of other income (expense), net in the consolidated statement of operations and comprehensive loss. Changes in the fair value of the contingent equity liability continued to be recognized until the occurrence of a triggering event, which occurred in May 2017 with the completion of the IPO. In May 2017, in connection with the completion of its IPO, the Company issued 538,149 common shares to AstraZeneca in satisfaction of its obligation to contingently issue the Second Tranche of equity securities pursuant to the license agreement (see Note 17) and remeasured the contingent equity liability to fair value. The Company recorded no research and development expense related to the AstraZeneca Agreement for the three months ended March 31, 2017. Agreement with Catalent In March 2015, the Company entered into a development and license agreement with Catalent U.K. Swindon Zydis Limited (“Catalent”) pursuant to which the Company obtained license rights to the Zydis technology in BHV-0223. BHV-0223 was developed under this agreement, and Catalent has manufactured BHV-0223 for clinical testing. Upon entering the agreement, the Company is obligated to pay Catalent up to $1,575 upon the achievement of specified regulatory and commercial milestones. The Company is also obligated to make royalty payments of a low single-digit percentage based on net sales of products licensed under the agreement. Under the agreement, the Company is responsible for conducting clinical trials and for preparing and filing regulatory submissions. The Company has the right to sublicense its rights under the Catalent 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 BHV-0223, infringes a third party’s patent. The development and license 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. The 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 the agreement on a country-by-country basis if the Company fails to meet specified development timelines, which it may extend in certain circumstances. The Company recorded no research and development expense related to the Catalent agreement during the three months ended March 31, 2017 and 2016.

Net Loss per Share

Net Loss per Share	3 Months Ended
	Mar. 31, 2017
Net Loss per Share
Net Loss per Share	13. Net Loss per Share Net Loss per Share Attributable to Common Shareholders of Biohaven Pharmaceutical Holding Company Ltd. Basic and diluted net loss per share attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd. was calculated as follows: Three Months Ended March 31, 2017 2016 Numerator: Net loss $ ) $ ) Net loss attributable to non-controlling interests — Accretion of beneficial conversion feature on Series A preferred shares ) — Net loss attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd. $ ) $ ) Denominator: Weighted average common shares outstanding—basic and diluted Net loss per share attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd.—basic and diluted $ ) $ ) The Company’s potential dilutive securities, which include stock options and warrants to purchase common shares, have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd. is the same. The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common shareholders for the periods indicated because including them would have had an anti-dilutive effect: Three Months Ended March 31, 2017 2016 Options to purchase common shares Warrants to purchase common shares The Company has agreed under its agreements with AstraZeneca and BMS to issue common shares upon the achievement of specified milestones or upon the occurrence of specified events (see Note 12). Because the necessary conditions for issuance of the shares had not been met as of March 31, 2017, the Company excluded these shares from the table above and from the calculation of diluted net loss per share for the three months ended March 31, 2017.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies
Commitments and Contingencies	14. Commitments and Contingencies Lease Agreement In December 2016, the Company entered into an assignment agreement to assume an operating lease for its office space in New Haven, Connecticut. The lease agreement expires in October 2018, and the Company has the option to extend the term through October 2021. During the three months ended March 31, 2017, the Company recorded rent expense of $16. The agreement requires future minimum lease payments for the years ending December 31, 2017 (remaining nine months) and 2018 of $30 and $35, respectively. License Agreements The Company has entered into license agreements with various parties under which it is obligated to make contingent and non-contingent payments (see Note 12). Research Commitments The Company has entered into agreements with several CROs to provide services in connection with its preclinical studies and clinical trials. As of March 31, 2017, the Company had committed to minimum payments under these arrangements totaling $12,473. Indemnification Agreements In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its board of directors that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. The Company’s amended and restated memorandum and article of association also provide for indemnification of directors and officers and officers in specific circumstances. To date, the Company has not incurred any material costs as a result of such indemnification provisions. The Company does not believe that the outcome of any claims under indemnification arrangements will have a material effect on its financial position, results of operations or cash flows, and it has not accrued any liabilities related to such obligations in its consolidated financial statements as of March 31, 2017 or December 31, 2016. Legal Proceedings The Company is not a party to any litigation and does not have contingency reserves established for any litigation liabilities.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2017
Related Party Transactions
Related Party Transactions	15. Related Party Transactions License Agreement with Yale On September 30, 2013, the Company entered into the Yale Agreement with Yale (see Note 12). Yale is a related party because the Company’s Chief Executive Officer is one of the inventors of the patents that the Company has licensed from Yale and, as such, is entitled to a specified share of the glutamate product-related royalty revenues that may be received by Yale under the Yale Agreement. As partial consideration for the license under the Yale Agreement, on September 30, 2013, the Company issued to Yale 250,000 common shares, representing 5.1% of the Company’s then outstanding equity on a fully diluted basis. The fair value of the shares, totaling $152, was recognized as research and development expense at the time of issuance of the shares. During the three months ended March 31, 2017 and 2016, the Company recognized research and development expense under the Yale Agreement of $0 and $8, respectively. As of March 31, 2017 and December 31, 2016, the Company owed no amounts to Yale. Guarantor and Co-Guarantor Warrants The Guarantor and Co-Guarantor of the Credit Agreement with Wells Fargo are each shareholders and members of the board of directors of the Company. The Company agreed to issue warrants to Guarantor and Co-Guarantor in exchange for their respective guaranties (see Notes 7 and 8). The warrants were issued on January 26, 2017, pursuant to which each director received a warrant to purchase 107,500 common shares at an exercise price of $9.2911 per share. Kleo Pharmaceuticals, Inc. On August 29, 2016, the Company executed a stock purchase agreement with Kleo to purchase 3,000,000 shares of Kleo common stock at a purchase price of $1.00 per share in an initial closing, which was completed on August 31, 2016, and committed to purchase an aggregate 5,500,000 additional shares of Kleo common stock at a purchase price of $1.00 per share (see Note 5). Kleo is a related party because the Company has determined that it exercises significant influence over the operating and financial policies of Kleo. In connection with its investment in Kleo, the Company received the right to designate two members of Kleo’s board of directors, who are the Chairman of the Company’s board of directors and another outside director of the Company. Also, the Chief Executive Officer and controlling stockholder of Kleo is a shareholder of the Company. In addition to the purchases under the stock purchase agreement described above, on August 29, 2016, the Company entered into an agreement with the Chief Executive Officer of Kleo to purchase 500,000 shares of Kleo common stock from him, which purchase was completed in March 2017 (see Note 5). As of March 31, 2017, the Company owned 27.9% of Kleo’s outstanding capital stock. The Company has also entered into a clinical development master services agreement with Kleo to assist Kleo with clinical development. As of March 31, 2017, the Company had not performed any services or received any payments under this agreement. Biohaven Pharmaceuticals, Inc. BPI is a related party because its three founders, each of whom beneficially owned one-third of the equity of BPI prior to the Company’s acquisition of BPI on December 31, 2016 (see Note 16), are shareholders of the Company and also serve as the Company’s Chairman of the board of directors, Chief Executive Officer and Chief Medical Officer, respectively. Since the Company’s incorporation in September 2013, the Company is deemed to have had a variable interest in BPI, and BPI is deemed to have been a VIE, of which the Company is the primary beneficiary. Accordingly, the Company has consolidated the results of BPI since September 2013. All transactions between the Company and BPI have been eliminated in consolidation. On December 31, 2016, the Company acquired 100% of the capital stock of BPI for aggregate purchase consideration of $595 in the form of promissory notes to each of the former stockholders of BPI. In May 2017, the promissory notes were paid in full (see Note 17).

Acquisition of Biohaven Pharmac

Acquisition of Biohaven Pharmaceuticals, Inc.	3 Months Ended
	Mar. 31, 2017
Acquisition of Biohaven Pharmaceuticals, Inc.
Acquisition of Biohaven Pharmaceuticals, Inc.	16. Acquisition of Biohaven Pharmaceuticals, Inc. On December 31, 2016, the Company entered into stock purchase agreements with each of the stockholders of BPI, acquiring 100% of the issued and outstanding shares of BPI for aggregate purchase consideration of $595. Prior to the acquisition, the Company was deemed to have had a variable interest in BPI, and BPI was deemed to be a VIE of which the Company was the primary beneficiary. As a result, the Company has consolidated the results of BPI since the Company’s incorporation in September 2013, and, prior to the acquisition of BPI, recognized a non-controlling interest in its consolidated balance sheet representing 100% of the capital stock of BPI not owned by the Company. The three founders of BPI, each of whom beneficially owned one-third of the equity of BPI, also serve as the Company’s Chairman of the board of directors, Chief Executive Officer, and Chief Medical Officer, respectively (see Note 15). The Company funded the acquisition through the issuance of promissory notes to each of the former stockholders of BPI. The notes are payable in five annual payments, the first four of which are interest only, with the final payment to include the principal balance outstanding plus any accrued and unpaid interest. The notes bear interest at a rate of 4.5% per annum and mature on December 31, 2021. The notes would become immediately due and payable upon specified events, including immediately prior to the consummation of the IPO of the Company’s common shares or upon the occurrence of a change of control of the Company. There are no affirmative, negative or financial covenants associated with the notes. In May 2017, in connection with the completion of the IPO, the notes became immediately due and payable, and the Company paid the notes, including principal and unpaid interest, in full (see Note 17). Because the Company consolidated BPI as a VIE prior to the acquisition, the acquisition of all of the capital stock of BPI did not result in a change of control for accounting purposes and was accounted for as an equity transaction. Accordingly, as of the acquisition date, the $86 carrying value of the non-controlling interest on December 31, 2016 was derecognized and the difference between the carrying value of the non-controlling interest of $86 and the purchase price of $595 was recorded as a $509 reduction to additional paid-in capital. There were no changes during the three months ended March 31, 2017. For the three months ended March 31, 2016, the Company recorded a net loss attributable to non-controlling interests of $35 when the Company consolidated BPI as a VIE.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2017
Subsequent Events
Subsequent Events	17. Subsequent Events For its unaudited consolidated financial statements as of March 31, 2017 and for the three months then ended, the Company evaluated subsequent events through June 16, 2017, the date on which those financial statements were issued. Increase in Authorized Common Shares On April 21, 2017, the Company effected an increase in the number of authorized common shares from 38,000,000 shares to 50,000,000 shares. Additionally, in connection with the completion of its IPO in May 2017, the Company amended its memorandum and articles of association to authorize the issuance of up to 200,000,000 no par value common shares and 10,000,000 no par value undesignated preferred shares. 2017 Equity Incentive Plan In April 2017, the Company’s shareholders approved the 2017 Plan, which became effective on May 3, 2017 in connection with the Company’s IPO. The 2017 Plan provides for the grant of incentive share options, nonstatutory share options, share appreciation rights, restricted share awards, restricted share unit awards, performance-based share awards and other share-based awards. Additionally, the 2017 Plan provides for the grant of performance cash awards. The number of common shares potentially issuable under the 2017 Plan is 7,611,971 shares, which is the sum of (i) 2,712,741 newly reserved shares, (ii) 372 shares which remained available for issuance under the 2014 Plan upon the effectiveness of the 2017 Plan and (iii) the maximum number of common shares subject to outstanding awards under the 2014 Plan that could potentially expire or terminate for any reason prior to exercise or settlement; be forfeited because of the failure to meet a contingency or condition required to vest such shares or otherwise return to the Company; or be reacquired or withheld (or not issued) to satisfy a tax withholding obligation in connection with an award or to satisfy the exercise price of an award. The number of common shares that may be issued under the 2017 Plan may be increased by the Company’s board of directors on January 1 of each year, beginning on January 1, 2018 and continuing through and including January 1, 2027, by a number of common shares determined by the Company’s board of directors in an amount not to exceed 4% of the total number of common shares outstanding on December 31 of the preceding calendar year. The common shares underlying any awards that expire or are otherwise terminated, are settled in cash, are repurchased by the Company, or are reacquired in satisfaction of tax withholding obligations or as consideration for the exercise price of an award under the 2017 Plan will be added back to the common shares available for issuance under the 2017 Plan. 2017 Employee Share Purchase Plan In April 2017, the Company’s shareholders approved the 2017 ESPP, which became effective on May 3, 2017 in connection with the Company’s IPO. A total of 339,139 common shares were initially reserved for issuance under this plan. The number of common shares that may be issued under the 2017 ESPP will automatically increase on January 1 of each year, beginning on January 1, 2018 and continuing through and including January 1, 2027, by the least of (i) 600,000 common shares, (ii) 1% of the total number of common shares outstanding on December 31 of the preceding calendar year and (iii) a number of shares determined by the Company’s board of directors. Initial Public Offering On May 3, 2017, the Company’s registration statement on Form S-1 relating to its IPO was declared effective by the SEC. The IPO closed on May 9, 2017 and the Company issued and sold 9,900,000 common shares at a public offering price of $17.00 per share for net proceeds of $152,889 after deducting underwriting discounts and commissions of $11,781 and other offering expenses of approximately $3,630. Upon the closing of the IPO, all convertible preferred shares then outstanding converted into an aggregate of 9,358,560 common shares. Upon the conversion of the preferred shares, the remaining unamortized portion of the BCF of $8,006 was reclassified to additional paid-in-capital as a deemed dividend. In addition on May 9, 2017, the underwriters of the IPO fully exercised their option to purchase addition shares, and on May 11, 2017, the Company issued and sold 1,485,000 additional common shares for additional net proceeds of $23,478 after deducting underwriting discounts, commissions, and other offering costs. Thus, the aggregate net proceeds to the Company from the IPO, after deducting underwriting discounts and commissions and other offering costs, were $176,367. In connection with the completion of its IPO, the Company issued an additional aggregate of 1,883,523 common shares to BMS and AstraZeneca in satisfaction of the obligation to contingently issue equity securities pursuant to the license agreements (see Note 12) for no additional consideration. The contingent equity liabilities were adjusted to fair value of $32,020 immediately prior to the completion of the IPO, and upon issuance of the common shares, the contingent equity liabilities were reclassified to equity. Payment of Notes Payable to Related Parties In connection with the closing of the Company’s IPO in May 2017, the notes payable to related parties were paid in full, including principal of $595. Accrued and unpaid interest of $9 was paid in June of 2017. Yale Agreement The Yale Agreement provides for a change-of-control payment to Yale upon the occurrence of a change-of-control event, as defined in the agreement, including an IPO. In April 2017, the agreement with Yale was amended such that if the change-of-control event is an IPO, the change-of-control payment shall be due to Yale on the first trading day when Yale is free to sell its equity interest in the Company and the change-of-control fee shall be reduced by the dollar value of Yale’s equity interest in the Company on the first trading day when Yale is free to sell its equity interest in the Company. Yale’s equity interest in the Company is subject to a lock-up agreement which generally restricts Yale’s shares from being traded until October 31, 2017, and accordingly, the amount due to Yale in connection with the change-of-control provision of the agreement, if any, will be determined upon expiration of the lock-up period. The Company will continue to remeasure the derivative liability to fair value at each reporting date and will recognize changes in the fair value of the derivative liability until the expiration of the lock-up period in October 2017 (see Note 17). Purchases of Kleo Common Stock In June 2017, the Company purchased 1,375,000 shares of Kleo common stock for cash consideration of $1,375 pursuant to its commitment under the Kleo SPA (see Note 5).

Summary of Significant Accoun25

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2017
Summary of Significant Accounting Policies
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of income and expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the accrual for research and development expenses and the valuation of common shares, stock options, warrants, derivative instruments and contingent equity instruments. In addition, management’s assessment of the Company’s ability to continue as a going concern involves the estimation of the amount and timing of future cash inflows and outflows. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates.
Unaudited Interim Consolidated Financial Information	Unaudited Interim Consolidated Financial Information The accompanying consolidated balance sheet as of March 31, 2017, the consolidated statements of operations and comprehensive loss and of cash flows for the three months ended March 31, 2017 and 2016, and the consolidated statement of convertible preferred shares and shareholders’ equity (deficit) as of March 31, 2017 are unaudited. The unaudited interim consolidated financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of March 31, 2017 and the results of its operations and its cash flows for the three months ended March 31, 2017 and 2016. The financial data and other information disclosed in these consolidated notes related to the three months ended March 31, 2017 and 2016 are unaudited. The results for the three months ended March 31, 2017 are not necessarily indicative of results to be expected for the year ending December 31, 2017, any other interim periods or any future year or period.
Restricted Cash	Restricted Cash As of December 31, 2016, current restricted cash consisted of $67 of cash received from investors as an advance payment for their participation in the second closing of the Company’s sale of Series A preferred shares. The Company closed the second and final tranche of its Series A preferred financing in February 2017. As a result, there was no current restricted cash as of March 31, 2017. As of March 31, 2017 and December 31, 2016, the Company’s non-current restricted cash consisted of a $60 certificate of deposit held as a security deposit in connection with the Company’s corporate credit card.
Deferred Offering Costs	Deferred Offering Costs The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such equity financings are consummated. After consummation of the equity financing, these costs are recorded in shareholders’ equity (deficit) as a reduction of proceeds generated as a result of the offering. Should the planned equity financing be abandoned, the deferred offering costs will be expensed immediately as a charge to operating expenses in the consolidated statement of operations and comprehensive loss. As of March 31, 2017 and December 31, 2016, the Company recorded deferred offering costs relating to its IPO of $2,399 and $134, respectively. The Company’s IPO was completed in May 2017 and these costs were recorded as a reduction to shareholders’ equity.
Equity Method Investments	Equity Method Investments Investments in non-public companies in which the Company owns less than a 50% equity interest and where it exercises significant influence over the operating and financial policies of the investee are accounted for using the equity method of accounting. The Company’s proportionate share of the net income or loss of the equity method investment is included in other income (expense), net in the consolidated statement of operations and comprehensive loss and results in a corresponding adjustment to the carrying value of the investment on the consolidated balance sheet. Dividends received reduce the carrying value of the investment. The Company periodically reviews the carrying value of its investment to determine if there has been an other-than-temporary decline in carrying value. A variety of factors are considered when determining if a decline in carrying value is other than temporary, including, among other factors, the financial condition and business prospects of the investee as well as the Company’s intent with regard to the investment.
Fair Value Measurements	Fair Value Measurements Certain assets of the Company are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: · Level 1— Quoted prices in active markets for identical assets or liabilities. · Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. · Level 3—Unobservable inputs that are supported by little or no market activity that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. The Company’s warrant liability, derivative liability and contingent equity liability are carried at fair value, determined according to the fair value hierarchy described above (see Note 3). The carrying values of other current assets, accounts payable, accrued expenses and notes payable under a credit agreement approximate their fair values due to the short-term nature of these assets and liabilities.
Research and Development Costs	Research and Development Costs Research and development costs are expensed as incurred. Research and development expenses consist of costs incurred in performing research and development activities, including salaries, share-based compensation and benefits, facilities costs, depreciation, third-party license fees, and external costs of outside vendors engaged to conduct clinical development activities and clinical trials as well as to manufacture clinical trial materials. Non-refundable prepayments for goods or services that will be used or rendered for future research and development activities are deferred and capitalized. Such amounts are recognized as an expense as the goods are delivered or the related services are performed, or until it is no longer expected that the goods will be delivered or the services rendered.
Research Contract Costs and Accruals	Research Contract Costs and Accruals The Company has entered into various research and development-related contracts with companies both inside and outside of the United States. These agreements are cancelable, and related payments are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies or clinical trials, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical accrual estimates have not been materially different from the actual costs.
Share-Based Compensation	Share-Based Compensation The Company measures stock options granted to employees and directors based on the fair value on the date of the grant and recognizes compensation expense of those awards, over the requisite service period, which is generally the vesting period of the respective award. Forfeitures are accounted for as they occur. Generally, the Company issues stock options with only service-based vesting conditions and records the expense for these awards using the straight-line method. The Company has not issued any stock options with performance-based vesting conditions. For share-based awards granted to consultants and non-employees, compensation expense is recognized over the period during which services are rendered by such consultants and non-employees until completed. At the end of each financial reporting period prior to completion of the service, the fair value of these awards is remeasured using the then-current fair value of the Company’s common shares and updated assumption inputs in the Black-Scholes option-pricing model. The Company classifies share-based compensation expense in its consolidated statement of operations and comprehensive loss in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified. The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model. Prior to May 2017, the Company was a private company and, accordingly, lacks company-specific historical and implied volatility information for its shares. Therefore, it estimates its expected share price volatility based on the historical volatility of publicly traded peer companies and expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded share price. The expected term of the Company’s stock options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The expected term of stock options granted to non-employees is equal to the contractual term of the option award. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that the Company has never paid cash dividends on common shares and does not expect to pay any cash dividends in the foreseeable future.
Warrant Liability	Warrant Liability In connection with entering into a credit agreement (see Note 7), the Company agreed to issue warrants to purchase common shares to two of the Company’s directors in connection with a guarantee of its obligations under the agreement (see Note 7). The Company classifies the warrants as a liability on its consolidated balance sheet because each warrant represents a freestanding financial instrument that is not indexed to the Company’s own shares. The warrant liability was initially recorded at fair value upon entering into the credit agreement and is subsequently remeasured to fair value at each reporting date. Changes in the fair value of the warrant liability are recognized as a component of other income (expense), net in the consolidated statement of operations and comprehensive loss. Changes in the fair value of the warrant liability will continue to be recognized until the warrants are exercised, expire or qualify for equity classification.
Derivative Liability	Derivative Liability The Company’s license agreement with Yale University (“Yale”) (see Note 12) provides for a change-of-control payment to Yale upon the occurrence of a change-of-control event, as defined in the agreement, including an IPO. The Company classifies the change-of-control payment obligation as a liability on its consolidated balance sheet because it represents a contingent obligation to pay a variable amount of cash that may be based, in part, on the value of the Company’s own shares. The derivative liability was initially recorded at fair value upon entering into the license agreement and is subsequently remeasured to fair value at each reporting date. Changes in the fair value of the derivative liability are recognized as a component of other income (expense), net in the consolidated statement of operations and comprehensive loss. In April 2017, the agreement with Yale was amended such that if the change-of-control event is an IPO, the change-of-control payment shall be due to Yale on the first trading day when Yale is free to sell its equity interest in the Company and the change-of-control fee shall be reduced by the dollar value of Yale’s equity interest in the Company on the first trading day when Yale is free to sell its equity interest in the Company. Yale’s equity interest in the Company is subject to a lock-up agreement, which generally restricts Yale’s shares from being traded until October 31, 2017 and accordingly, the amount due to Yale in connection with the change-of-control provision of the agreement, if any, will be determined upon expiration of the lock-up period. The Company will continue to remeasure the derivative liability to fair value at each reporting date and will recognize changes in the fair value of the derivative liability until the expiration of the lock-up agreement in October 2017 (see Note 17).
Contingent Equity Liability	Contingent Equity Liability The Company’s license agreements with AstraZeneca and BMS (see Note 12) require the Company to issue shares of capital stock upon the occurrence of specified financing or change-of-control events or development milestones, as defined in the agreements. In each agreement, the class and number of shares to be issued upon a triggering event were not known upon entering into the license agreements; however, the dollar amount of the shares to be issued upon a triggering event is fixed. The Company classifies these contingent obligations to issue shares as a liability on its consolidated balance sheet because each represents an obligation to issue a variable number of shares for a fixed dollar amount. Each contingent equity liability was initially recorded at fair value upon entering into each respective agreement and is subsequently remeasured to fair value at each reporting date. Changes in the fair values of the contingent equity liabilities are recognized as a component of other income (expense), net in the consolidated statement of operations and comprehensive loss. Changes in the fair value of the contingent equity liabilities will continue to be recognized until the occurrence of a respective triggering event. In May 2017, upon closing of the IPO, the conditions for issuing shares to BMS and AstraZeneca under the terms of the respective license agreements were satisfied, and accordingly, the Company issued 1,345,374 and 538,149 common shares, respectively, to BMS and AstraZeneca. The contingent equity liabilities were remeasured to fair value in the aggregate amount of $32,020 immediately prior to the completion of the IPO, and upon issuance of the common shares, the contingent equity liabilities were reclassified to shareholders’ equity (see Note 17).
Net Loss per Share Attributable to Common Shareholders of Biohaven Pharmaceutical Holding Company Ltd.	Net Loss per Share Attributable to Common Shareholders of Biohaven Pharmaceutical Holding Company Ltd. The Company follows the two-class method when computing net income (loss) per share as the Company has issued shares that meet the definition of participating securities. The two-class method determines net income (loss) per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires income available to common shareholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. Net income (loss) per share attributable to common shareholders is calculated based on net income (loss) attributable to Biohaven Pharmaceutical Holding Company Ltd. and excludes net income (loss) attributable to non-controlling interests for relevant periods. Basic net income (loss) per share attributable to common shareholders is computed by dividing the net income (loss) attributable to common shareholders by the weighted average number of common shares outstanding for the period. Diluted net income (loss) attributable to common shareholders is computed by adjusting net income (loss) attributable to common shareholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net income (loss) per share attributable to common shareholders is computed by dividing the diluted net income (loss) attributable to common shareholders by the weighted average number of common shares outstanding for the period, including potential dilutive common shares. For purpose of this calculation, outstanding options, warrants to purchase common shares, convertible preferred shares and contingently issuable equity are considered potential dilutive common shares. The Company’s convertible preferred shares contractually entitle the holders of such shares to participate in dividends but contractually do not require the holders of such shares to participate in losses of the Company. Accordingly, in periods in which the Company reports a net loss attributable to common shareholders, diluted net loss per share attributable to common shareholders is the same as basic net loss per share attributable to common shareholders, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In January 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805) — Clarifying the Definition of a Business (“ASU 2017-01”). ASU 2017-01 finalizes previous proposals regarding shareholder concerns that the definition of a business is applied too broadly. The guidance assists entities with evaluating whether transactions should be accounted for as acquisitions of assets or of businesses. The amendments are effective for annual periods beginning after December 15, 2017, including interim periods within those periods. The Company is currently evaluating the impact that the adoption of ASU 2017-01 will have on its consolidated financial statements. In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfer of Assets Other than Inventory (“ASU 2016-16”), which requires the recognition of the income tax consequences of an intra-entity transfer of an asset, other than inventory, when the transfer occurs. The standard is effective for annual periods beginning after December 15, 2017, including interim periods within those fiscal years. The Company is currently evaluating the impact that the adoption of ASU 2016-16 will have on its consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments (“ASU 2016-15”), to address diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The standard is effective for annual periods beginning after December 15, 2017, including interim periods within those fiscal years. The Company is currently evaluating the impact that the adoption of ASU 2016-15 will have on its consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (“ASU 2016-02”), which sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e., lessees and lessors). The new standard requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee. This classification will determine whether lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease, respectively. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. Leases with a term of 12 months or less will be accounted for similar to existing guidance for operating leases today. ASU 2016-02 (Accounting Standards Codification (“ASC”) Topic 842) supersedes the previous leases standard, ASC 840, Leases . The standard is effective for public entities for annual periods beginning after December 15, 2018 and for interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the impact that the adoption of ASU 2016-02 will have on its consolidated financial statements. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”), which supersedes existing revenue recognition guidance under GAAP. The standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those goods or services. The standard defines a five-step process to achieve this principle, and will require companies to use more judgment and make more estimates than under the current guidance. The Company expects that these judgments and estimates will include identifying performance obligations in the customer contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. ASU 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date , which delays the effective date of ASU 2014-09 such that the standard is effective for public entities for annual periods beginning after December 15, 2017 and for interim periods within those fiscal years. Early adoption of the standard is permitted for annual periods beginning after December 15, 2016. In March 2016, the FASB issued ASU No. 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (“ASU 2016-08”), which further clarifies the implementation guidance on principal versus agent considerations in ASU 2014-09. In April 2016, the FASB issued ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing , clarifying the implementation guidance on identifying performance obligations and licensing. Specifically, the amendments in this update reduce the cost and complexity of identifying promised goods or services and improve the guidance for determining whether promises are separately identifiable. The amendments in this update also provide implementation guidance on determining whether an entity’s promise to grant a license provides a customer with either a right to use the entity’s intellectual property (which is satisfied at a point in time) or a right to access the entity’s intellectual property (which is satisfied over time). In May 2016, the FASB issued ASU No. 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients (“ASU 2016-12”), which clarifies the objective of the collectability criterion, presentation of taxes collected from customers, non-cash consideration, contract modifications at transition, completed contracts at transition and how guidance in ASU 2014-09 is retrospectively applied. ASU 2016-08, ASU 2016-10 and ASU 2016-12 have the same effective dates and transition requirements as ASU 2014-09. The Company is currently evaluating the impact that the adoption that these standards will have on its consolidated financial statements, if and when it generates revenue.

Fair Value of Financial Asset26

Fair Value of Financial Assets and Liabilities (Tables)	3 Months Ended
	Mar. 31, 2017
Fair Value of Financial Assets and Liabilities
Summary of the Company's financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy	Fair Value Measurements as of March 31, 2017 Using: Level 1 Level 2 Level 3 Total Liabilities: Warrant liability $ — $ — $ $ Derivative liability — — Contingent equity liability — — $ — $ — $ $ Fair Value Measurements as of December 31, 2016 Using: Level 1 Level 2 Level 3 Total Liabilities: Warrant liability $ — $ — $ $ Derivative liability — — Contingent equity liability — — $ — $ — $ $
Summary of roll forward of aggregate fair values of the Company's warrant liability, derivative liability and contingent equity liability	Warrant Derivative Contingent Liability Liability Equity Liability Balance at December 31, 2016 $ $ $ Change in fair value ) Balance at March 31, 2017 $ $ $

Prepaid Expenses and Other Cu27

Prepaid Expenses and Other Current Assets (Tables)	3 Months Ended
	Mar. 31, 2017
Prepaid Expenses and Other Current Assets
Schedule of prepaid expenses and other current	March 31, December 31, 2017 2016 Prepaid clinical trial costs $ $ Other $ $

Equity Method Investment (Table

Equity Method Investment (Tables)	3 Months Ended
	Mar. 31, 2017
Equity Method Investment
Schedule of carrying value of equity method investment	Carrying Value Balance at December 31, 2016 $ Purchases of Kleo common stock Loss recognized in connection with equity method investment ) Balance at March 31, 2017 $
Schedule of equity investments and summarized financial information for equity investees	March 31, December 31, 2017 2016 Current assets $ $ Total assets $ $ Current liabilities $ $ Total liabilities $ $ Three Months Ended March 31, 2017 Revenue $ — Loss from Operations $ ) Net loss $ )

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2017
Accrued Expenses
Schedule of accrued expenses	March 31, December 31, 2017 2016 Accrued employee compensation and benefits $ $ Accrued clinical trial costs Accrued professional fees Accrued income taxes Other — $ $

Share-Based Compensation (Table

Share-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2017
Schedule of assumptions that the Company used to determine the grant-date fair value of stock options granted	Three Months Ended Risk-free interest rate % Expected term (in years) Expected volatility % Expected dividend yield % Exercise price $ Fair value of common share $
Summary of stock option activity	Weighted Weighted Average Average Remaining Aggregate Number of Exercise Contractual Intrinsic Shares Price Term Value (in years) Outstanding as of December 31, 2016 $ $ Granted Exercised — — Forfeited — — Outstanding as of March 31, 2017 $ $ $ Options exercisable as of March 31, 2017 $ $ $ Options unvested as of March 31, 2017 $ $ $
Summary of classification of share-based compensation expense	Three Months Ended March 31, 2017 2016 Research and development expenses $ $ General and administrative expenses $ $
Non-employees
Schedule of assumptions that the Company used to determine the grant-date fair value of stock options granted	Three Months Ended Risk-free interest rate % Expected term (in years) Expected volatility % Expected dividend yield % Exercise price $ Fair value of common share $

Net Loss per Share (Tables)

Net Loss per Share (Tables)	3 Months Ended
	Mar. 31, 2017
Net Loss per Share
Schedule of basic and diluted net loss per share	Three Months Ended March 31, 2017 2016 Numerator: Net loss $ ) $ ) Net loss attributable to non-controlling interests — Accretion of beneficial conversion feature on Series A preferred shares ) — Net loss attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd. $ ) $ ) Denominator: Weighted average common shares outstanding—basic and diluted Net loss per share attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd.—basic and diluted $ ) $ )
Schedule of potentially anti-dilutive securities excluded from calculation of diluted net loss per share	Three Months Ended March 31, 2017 2016 Options to purchase common shares Warrants to purchase common shares

Nature of the Business and Ba32

Nature of the Business and Basis of Presentation (Details) - Majority Shareholder - Biohaven Pharmaceuticals, Inc. $ in Thousands	12 Months Ended
	Dec. 31, 2016item	Mar. 31, 2017USD ($)	Mar. 31, 2016
Related Party Transactions
Number of founders | item	3
Equity share percentage owned by each founders	33.33%
Fair value of BPI | $		$ 0
Net loss attributable to non-controlling interest			100.00%
Ownership interest acquired	100.00%

Nature of the Business and Ba33

Nature of the Business and Basis of Presentation - Stock Split & Public Offering (Details) $ / shares in Units, $ in Thousands	May 11, 2017USD ($)$ / sharesshares	May 09, 2017USD ($)$ / sharesshares	May 31, 2017USD ($)	Oct. 31, 2016	Feb. 29, 2016USD ($)$ / sharesshares	Mar. 31, 2017USD ($)$ / sharesshares	Jul. 31, 2016USD ($)$ / sharesshares	Mar. 31, 2016USD ($)	Apr. 30, 2017shares	Apr. 21, 2017shares	Dec. 31, 2016$ / sharesshares
Stock Split
Stock Split				500
Public Offering
Issuance of common shares | shares					429,000		1,090,500
Fair value of common share | $ / shares					$ 7		$ 7.70
Net proceeds from issuance of shares, after deducting underwriting discounts and commissions and other offering expenses			$ 176,367
Other offering expenses					$ 23	$ 2,049	$ 97	$ 23
Common stock, shares authorized | shares						38,000,000					38,000,000
Common stock, par value (in dollars per share) | $ / shares						$ 0					$ 0
Preferred stock, shares authorized | shares						11,242,172					11,242,172
Preferred stock, par value (in dollars per share) | $ / shares						$ 0					$ 0
Subsequent Event
Public Offering
Aggregate net proceeds from the IPO and underwriters issuance	$ 176,367
Common stock, shares authorized | shares	200,000,000								50,000,000	50,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0
Preferred stock, shares authorized | shares	10,000,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 0
Subsequent Event | Initial public offering
Public Offering
Issuance of common shares | shares		9,900,000
Fair value of common share | $ / shares		$ 17
Net proceeds from issuance of shares, after deducting underwriting discounts and commissions and other offering expenses		$ 152,889
Underwriting discounts and commissions		11,781
Other offering expenses		$ 3,630
Convertible preferred stock converted into shares of common stock | shares		9,358,560
Subsequent Event | Over allotment option
Public Offering
Issuance of common shares | shares	1,485,000
Net proceeds from issuance of shares, after deducting underwriting discounts and commissions and other offering expenses	$ 23,478
Underwriting discounts and commissions	1,767
Aggregate net proceeds from the IPO and underwriters issuance	$ 176,367
Subsequent Event | Over allotment option | BMS and AstraZenca
Public Offering
Issuance of common shares | shares	1,883,523	1,883,523
Common shares value issued	$ 0

Nature of the Business and Ba34

Nature of the Business and Basis of Presentation - Going Concern(Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	May 31, 2017	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015
Going Concern
Net losses		$ 22,753	$ 2,951
Accumulated deficit		94,209		$ 75,456
Cash		$ 52,286	$ 2,895	$ 23,565	$ 1,460
Net proceeds from issuance of shares, after deducting underwriting discounts and commissions and other offering expenses	$ 176,367

Summary of Significant Accoun35

Summary of Significant Accounting Policies (Details) $ in Thousands	May 09, 2017shares	May 31, 2017USD ($)shares	Feb. 29, 2016shares	Sep. 30, 2013shares	Mar. 31, 2017USD ($)director	Jul. 31, 2016shares	Dec. 31, 2016USD ($)
Restricted Cash
Restricted Cash Current | $							$ 67
Restricted Cash Non Current | $					$ 60		60
Deferred Offering Costs
Deferred offering costs | $					$ 2,399		134
Warrant Liability
Number of directors to whom the Company agreed to issue warrants | director					2
Contingent Equity Liability
Issuance of common shares			429,000			1,090,500
Certificate of deposit
Restricted Cash
Restricted Cash Non Current | $					$ 60		60
Series A preferred shares
Restricted Cash
Restricted Cash Current | $					$ 0		$ 67
Initial public offering | Subsequent Event
Contingent Equity Liability
Issuance of common shares	9,900,000
Fair value of contingent equity liabilities | $		$ 32,020
Product related collaborative arrangements | BMS Agreement
Contingent Equity Liability
Issuance of common shares		1,345,374
Product related collaborative arrangements | BMS Agreement | Initial public offering | Subsequent Event
Contingent Equity Liability
Issuance of common shares		1,345,374
Product related collaborative arrangements | AstraZeneca
Contingent Equity Liability
Issuance of common shares		538,149
Product related collaborative arrangements | AstraZeneca | Initial public offering | Subsequent Event
Contingent Equity Liability
Issuance of common shares		538,149
Collaborative arrangement | Yale Agreement
Contingent Equity Liability
Issuance of common shares				250,000

Fair Value of Financial Asset36

Fair Value of Financial Assets and Liabilities (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017USD ($)director	Dec. 31, 2016USD ($)
Fair value of Financial Assets and Liabilities
Transfer between levels 1 to level 2	$ 0	$ 0
Transfer between levels 2 to level 1	0	0
Transfer in and out of level 3	$ 0	$ 0
Number of directors to whom the Company agreed to issue warrants | director	2
Expected dividend yield	0.00%
Probability of occurrence of event that was most probable of triggering the issuance of shares	85.00%	75.00%
Value of the contingently issuable equity	$ 18,750	$ 18,750
Discount assessed	0.00%	0.00%
Fair value of the contingent equity liability	$ 15,938	$ 14,063
Recurring
Fair value of Financial Assets and Liabilities
Fair value of liabilities	23,770	20,230
Level 3 | Recurring
Fair value of Financial Assets and Liabilities
Fair value of liabilities	23,770	20,230
Warrants to purchase common shares | Recurring
Fair value of Financial Assets and Liabilities
Fair value of liabilities	1,234	780
Warrants to purchase common shares | Level 3 | Recurring
Fair value of Financial Assets and Liabilities
Fair value of liabilities	1,234	780
Derivative liability | Recurring
Fair value of Financial Assets and Liabilities
Fair value of liabilities	223	512
Derivative liability | Level 3 | Recurring
Fair value of Financial Assets and Liabilities
Fair value of liabilities	223	512
Contingent equity liability | Recurring
Fair value of Financial Assets and Liabilities
Fair value of liabilities	22,313	18,938
Contingent equity liability | Level 3 | Recurring
Fair value of Financial Assets and Liabilities
Fair value of liabilities	$ 22,313	$ 18,938
Maximum
Fair value of Financial Assets and Liabilities
Expected timing of event that was most probable of triggering the issuance of shares	1 year	1 year

Fair Value of Financial Asset37

Fair Value of Financial Assets and Liabilities - Valuation of Contingent Equity Liability (Details) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended	12 Months Ended
	Feb. 28, 2017USD ($)$ / sharesshares	Oct. 31, 2016USD ($)tranche$ / sharesshares	Mar. 31, 2017USD ($)shares	Dec. 31, 2016USD ($)	Jul. 31, 2016$ / shares	Feb. 29, 2016$ / shares
Net proceeds			$ 40,000
Fair value of the contingent equity liability			$ 15,938	$ 14,063
Probability of occurrence of event that was most probable of triggering the issuance of shares			85.00%	75.00%
Value of the contingently issuable equity			$ 18,750	$ 18,750
Discount assessed			0.00%	0.00%
Issuance price per share | $ / shares					$ 7.70	$ 7
Maximum
Expected timing of event that was most probable of triggering the issuance of shares			1 year	1 year
AstraZeneca
Number of tranches in which contingently issuable equity is issuable | tranche		2
Fixed dollar amount of tranches		$ 5,000
Total amount of tranches		10,000
AstraZeneca | Second tranche
Fair value of the contingent equity liability			$ 6,375	$ 4,875
Probability of occurrence of event that was most probable of triggering the issuance of shares			85.00%	65.00%
Value of the contingently issuable equity			$ 7,500	$ 7,500
Discount assessed			0.00%	0.00%
AstraZeneca | Second tranche | Maximum
Expected timing of event that was most probable of triggering the issuance of shares			3 months	1 year
Series A Convertible Preferred Shares
Net proceeds	$ 38,636	$ 37,295
Preferred stock issued and sold | shares	4,305,182	4,305,209	4,305,182
Aggregate fair value			$ 38,636
Issuance price per share | $ / shares	$ 9.2911	$ 9.2911
Series A Convertible Preferred Shares | AstraZeneca
Preferred stock issued and sold | shares		538,150
Issuance price per share | $ / shares		$ 9.2911
Series A Convertible Preferred Shares | AstraZeneca | First tranche
Preferred stock issued and sold | shares		538,150
Aggregate fair value		$ 5,000
Issuance price per share | $ / shares		$ 9.2911

Fair Value of Financial Asset38

Fair Value of Financial Assets and Liabilities - Fair values of the company's liabilities (Details) - USD ($) $ in Thousands	May 09, 2017	Feb. 17, 2017	May 31, 2017	Feb. 29, 2016	Mar. 31, 2017	Jul. 31, 2016
Fair values of the company's liabilities
Stock Issued During Period, Shares, New Issues				429,000		1,090,500
Recognized fair value of BCF as a reduction to series A preferred shares and corresponding adjustment to additional paid in capital		$ 12,006			$ (12,006)
Warrants to purchase common shares
Fair values of the company's liabilities
Balance at the beginning					780
Change in fair value					454
Balance at the end					1,234
Derivative liability
Fair values of the company's liabilities
Balance at the beginning					512
Change in fair value					(289)
Balance at the end					223
Contingent equity liability
Fair values of the company's liabilities
Change in fair value					$ 3,375
Initial public offering | Subsequent Event
Fair values of the company's liabilities
Stock Issued During Period, Shares, New Issues	9,900,000
Product related collaborative arrangements | BMS Agreement
Fair values of the company's liabilities
Stock Issued During Period, Shares, New Issues			1,345,374
Product related collaborative arrangements | BMS Agreement | Initial public offering | Subsequent Event
Fair values of the company's liabilities
Stock Issued During Period, Shares, New Issues			1,345,374
Product related collaborative arrangements | AstraZeneca
Fair values of the company's liabilities
Stock Issued During Period, Shares, New Issues			538,149
Product related collaborative arrangements | AstraZeneca | Initial public offering | Subsequent Event
Fair values of the company's liabilities
Stock Issued During Period, Shares, New Issues			538,149

Prepaid Expenses and Other Cu39

Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Prepaid Expenses and Other Current Assets
Prepaid clinical trial costs	$ 860	$ 388
Other	23	15
Total prepaid expenses and other current assets	$ 883	$ 403

Equity Method Investment - Stoc

Equity Method Investment - Stock purchase agreement with Kleo (Details) $ / shares in Units, $ in Thousands	Mar. 30, 2017USD ($)$ / sharesshares	Aug. 29, 2016directortranche$ / sharesshares	Mar. 31, 2017USD ($)shares	Dec. 31, 2016
Equity Method Investment
Cash payment for purchase of equity method investment			$ 1,624
Common stock value for purchase of kleo office stock holder stock			352
Proportionate share of net loss in Kleo			$ 218
Common Shares
Equity Method Investment
Stock Issued During the Period Shares Equity Method Investments | shares			32,500
Common stock value for purchase of kleo office stock holder stock			$ 352
Kleo
Equity Method Investment
Shares of Kleo common stock purchased | shares		3,000,000
Additional shares of Kleo common stock purchased | shares		5,500,000	1,875,000
Price per share | $ / shares		$ 1
Number of equal tranches of shares to be purchased | tranche		4
Shares purchased in equal tranches | shares		1,375,000	1,375,000
Period of time shares begin to be purchased in equal tranches after the initial closing		6 months
Period of time shares are purchased after the initial purchase		3 months
Cash payment for purchase of equity method investment			$ 1,976
Shares of Kleo common stock purchased from Chief Executive Officer | shares		500,000
Cash payment for purchase of Kleo officer and stockholder shares	$ 250
Issuance of common shares for purchase of Kleo office and stockholder shares (in shares) | shares	32,500
Fair value of share price | $ / shares	$ 10.82
Common stock value for purchase of kleo office stock holder stock	$ 352
Number to designate to Kleo's board of directors | director		2
Ownership percentage			27.90%	18.60%
Total number of directors on Kleo's board of directors | director		5
Proportionate share of net loss in Kleo			$ 218

Equity Method Investment - Carr

Equity Method Investment - Carrying value and Summarized financial information for Kleo (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Equity Method Investment
Carrying value of investment in Kleo	$ 2,753	$ 4,511	$ 2,753
Carrying value of equity method investment
Beginning balance	2,753
Purchases of Kleo common stock	1,624
Loss recognized in connection with equity method investment	(218)
Ending balance	4,511
Kleo
Equity Method Investment
Carrying value of investment in Kleo	2,753	4,511	2,753
Carrying value of equity method investment
Beginning balance	2,753
Purchases of Kleo common stock	1,976
Loss recognized in connection with equity method investment	(218)
Ending balance	4,511
Assets
Current assets		4,243	4,269
Total assets		4,657	4,317
Liabilities
Current liabilities		601	413
Total liabilities		$ 1,600	$ 656
Profit/loss
Loss from Operations	(1,174)
Net loss	$ (1,169)

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Accrued expenses
Accrued employee compensation and benefits	$ 311	$ 27
Accrued clinical trial costs	4,639	2,204
Accrued professional fees	1,689	516
Accrued income taxes	292	99
Other		134
Total accrued expenses	$ 6,931	$ 2,980

Notes Payable - Credit Agreemen

Notes Payable - Credit Agreement (Details) $ in Thousands	Aug. 30, 2016USD ($)	Mar. 31, 2017USD ($)	Jan. 26, 2017USD ($)	Dec. 31, 2016USD ($)
Guarantor And Co-Guarantor Warrants
Fair Value Of Warrant Liabilities		$ 1,234		$ 780
Interest expense		305
Accretion of debt discount		273
Unamortized debt discount		511
Credit Agreement | Common stock warrants issued in connection with the Credit Agreement | Common Shares
Guarantor And Co-Guarantor Warrants
Fair Value Of Warrant Liabilities	$ 934	$ 1,234	$ 934	$ 780
Credit Agreement | Common stock warrants issued in connection with the Credit Agreement | Notes Payable | Common Shares
Guarantor And Co-Guarantor Warrants
Arrangement fee	150
Incurred legal costs	47
Credit Agreement | Common stock warrants issued to Guarantor in connection with the Credit Agreement | Common Shares
Guarantor And Co-Guarantor Warrants
Value of shares into which the warrant may be converted	1,000
Credit Agreement | Common stock warrants issued to Co-Guarantor in connection with the Credit Agreement | Common Shares
Guarantor And Co-Guarantor Warrants
Value of shares into which the warrant may be converted	$ 1,000
Credit Agreement | Wells Fargo Term Loan
Credit Agreement
Credit agreement term	1 year
Principal Amount	$ 5,000
Amount borrowed	$ 5,000
Line of credit interest rate (as a percent)		2.48%
Reimbursement to Guarantor (as a percent)	0.5
Principal payments due		$ 0
Repayments of principal		$ 0
Credit Agreement | Wells Fargo Term Loan | LIBOR
Credit Agreement
Margin added to the reference rate to compute the variable rate (as a percent)	1.50%
Margin added to the reference rate in the event of a default (as a percent)		4.00%

Notes Payable - Notes Payable t

Notes Payable - Notes Payable to Related Parties (Details)	Dec. 31, 2016USD ($)	May 31, 2017USD ($)	Mar. 31, 2017installment	Dec. 31, 2016USD ($)
Majority Shareholder | Biohaven Pharmaceuticals, Inc.
Notes Payable to Related Parties
Ownership interest acquired	100.00%			100.00%
Aggregate purchase consideration	$ 595,000			$ 595,000
Number of installments in which notes are payable | installment			5
Number of interest only related party notes payable installments | installment			4
Interest rate of notes			4.50%
Initial public offering | Subsequent Event
Notes Payable to Related Parties
Repayment of principal amount to related party		$ 595,000
Repayment of interest amount to related party		$ 9,000

Warrants - ALS Biopharma Warran

Warrants - ALS Biopharma Warrants (Details) - Common Shares	Aug. 10, 2015$ / sharesshares
Common stock warrants issued, immediately exercisable
ALS Biopharma Warrants
Shares that warrant can purchase | shares	275,000
Exercise price (in dollars per share) | $ / shares	$ 5.60
Exercise period from date of issuance	10 years
Common stock warrants issued, exercisable upon filing drug application
ALS Biopharma Warrants
Shares that warrant can purchase | shares	325,000
Exercise price (in dollars per share) | $ / shares	$ 5.60
Exercise period from date of issuance	10 years

Warrants -Guarantor and Co-Guar

Warrants -Guarantor and Co-Guarantor Warrants (Details) - USD ($) $ / shares in Units, $ in Thousands	Jan. 26, 2017	Mar. 31, 2017	Dec. 31, 2016	Aug. 30, 2016
Guarantor and Co-Guarantor Warrants [Abstract]
Fair Value Of Warrant Liabilities		$ 1,234	$ 780
Change in fair value of warrant liability		(454)
Credit Agreement | Common stock warrants issued in connection with the Credit Agreement | Common Shares
Guarantor and Co-Guarantor Warrants [Abstract]
Fair Value Of Warrant Liabilities	$ 934	1,234	$ 780	$ 934
Exercise price (in dollars per share)	$ 9.2911
Exercise period from date of issuance	5 years
Exercise period from date of initial public offering	2 years
Credit Agreement | Common stock warrants issued in connection with the Credit Agreement | Other income (expense)
Guarantor and Co-Guarantor Warrants [Abstract]
Change in fair value of warrant liability		$ 454
Credit Agreement | Common stock warrants issued to Guarantor in connection with the Credit Agreement | Common Shares
Guarantor and Co-Guarantor Warrants [Abstract]
Value of shares into which the warrant may be converted				1,000
Shares that warrant can purchase	107,500
Credit Agreement | Common stock warrants issued to Co-Guarantor in connection with the Credit Agreement | Common Shares
Guarantor and Co-Guarantor Warrants [Abstract]
Value of shares into which the warrant may be converted				$ 1,000
Shares that warrant can purchase	107,500

Convertible Preferred Shares (D

Convertible Preferred Shares (Details)	1 Months Ended			3 Months Ended
	May 31, 2017shares	Feb. 28, 2017USD ($)item$ / sharesshares	Oct. 31, 2016USD ($)item$ / sharesshares	Mar. 31, 2017USD ($)shares	Oct. 01, 2017$ / shares	Dec. 31, 2016shares	Jul. 31, 2016$ / shares	Feb. 29, 2016$ / shares
Preferred Shares
Preferred stock, shares authorized | shares				11,242,172		11,242,172
Net proceeds				$ 40,000,000
Fair value of common share | $ / shares							$ 7.70	$ 7
Accretion of beneficial conversion feature on series A preferred shares				$ (4,000,000)
Series A Convertible Preferred Shares
Preferred Shares
Preferred stock, shares authorized | shares				11,242,172
Preferred stock issued and sold | shares		4,305,182	4,305,209	4,305,182
Number of placement agents | item		2	2
Net proceeds		$ 38,636,000	$ 37,295,000
Fair value of common share | $ / shares		$ 9.2911	$ 9.2911
Offering costs		$ 2,606,000	$ 2,705,000
Issuance of common stock, issuance costs		1,364,000	1,730,000	$ 1,364,000
Issuance of Series A preferred shares as payment of offering costs		105,009	105,010
Value of Preferred Share		1,242,000	$ 975,000
Accretion of beneficial conversion feature on series A preferred shares		$ (2,406,000)		$ 4,000,000
Maximum price for fair value of the underlying common shares | shares		9.85
Shares issued on conversion of preferred stock | shares	9,358,560
Shares issued on conversion of preferred stock to common stock				1
Shares issued on conversion of preferred stock to common stock if company fails to initiate Phase 3				0.001
Share Price if company fails to initiate Phase 3 | $ / shares					7.0613
Dividend rate (as a percent)				8.00%
Series A Convertible Preferred Shares | Minimum
Preferred Shares
Net proceeds				$ 50,000,000
Series A Convertible Preferred Shares | AstraZeneca
Preferred Shares
Preferred stock issued and sold | shares			538,150
Fair value of common share | $ / shares			$ 9.2911
Aggregate fair value			$ 5,000,000

Common Shares (Details)

Common Shares (Details)	1 Months Ended	3 Months Ended
	Feb. 29, 2016USD ($)$ / sharesshares	Mar. 31, 2017USD ($)Vote$ / sharesshares	Jul. 31, 2016USD ($)$ / sharesshares	Mar. 31, 2016USD ($)	May 11, 2017shares	Apr. 30, 2017shares	Apr. 21, 2017shares	Dec. 31, 2016$ / sharesshares
Number of shares authorized | shares		38,000,000						38,000,000
Common stock, par value (in dollars per share) | $ / shares		$ 0						$ 0
Number of votes | Vote		1
Dividends declared		$ 0
Issuance of common shares | shares	429,000		1,090,500
Issuance price per share | $ / shares	$ 7		$ 7.70
Proceeds from issuance of common shares	$ 2,980,000		$ 8,299,000	$ 3,003,000
Issuance costs	$ 23,000	2,049,000	$ 97,000	$ 23,000
Put option
Fair value of put option		$ 0
Subsequent Event
Number of shares authorized | shares					200,000,000	50,000,000	50,000,000

Common Shares- Other Info (Deta

Common Shares- Other Info (Details) - USD ($) $ / shares in Units, $ in Thousands	May 11, 2017	May 09, 2017	May 31, 2017	Feb. 29, 2016	Mar. 31, 2017	Jul. 31, 2016	Mar. 31, 2016	Apr. 30, 2017	Apr. 21, 2017	Dec. 31, 2016
Issuance of common shares				429,000		1,090,500
Issuance price per share				$ 7		$ 7.70
Net proceeds from issuance of shares, after deducting underwriting discounts and commissions and other offering expenses			$ 176,367
Other offering expenses				$ 23	$ 2,049	$ 97	$ 23
Common stock, shares authorized					38,000,000					38,000,000
Common stock, par value (in dollars per share)					$ 0					$ 0
Preferred stock, shares authorized					11,242,172					11,242,172
Preferred stock, par value (in dollars per share)					$ 0					$ 0
Subsequent Event
Aggregate net proceeds from the IPO and underwriters issuance	$ 176,367
Common stock, shares authorized	200,000,000							50,000,000	50,000,000
Common stock, par value (in dollars per share)	$ 0
Preferred stock, shares authorized	10,000,000
Preferred stock, par value (in dollars per share)	$ 0
Subsequent Event | Initial public offering
Issuance of common shares		9,900,000
Issuance price per share		$ 17
Net proceeds from issuance of shares, after deducting underwriting discounts and commissions and other offering expenses		$ 152,889
Underwriting discounts and commissions		11,781
Other offering expenses		$ 3,630
Convertible preferred stock converted into shares of common stock		9,358,560
Subsequent Event | Over allotment option
Issuance of common shares	1,485,000
Net proceeds from issuance of shares, after deducting underwriting discounts and commissions and other offering expenses	$ 23,478
Net proceeds from underwriting	23,478
Underwriting discounts and commissions	1,767
Aggregate net proceeds from the IPO and underwriters issuance	$ 176,367
Subsequent Event | Over allotment option | BMS and AstraZenca
Issuance of common shares	1,883,523	1,883,523
Common shares value issued	$ 0

Share-Based Compensation - 2014

Share-Based Compensation - 2014 Equity Incentive Plan (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Jan. 31, 2017	Dec. 31, 2016
Share-Based Compensation
Stock option granted		0
Share-based compensation expense	$ 1,886	$ 687
2014 Equity Incentive Plan
Share-Based Compensation
Shares authorized	4,899,230		4,899,230	4,000,000
Number of shares remained available for future grant	553,886	1,034,805
Stock option granted	480,919
2014 Equity Incentive Plan | Minimum
Share-Based Compensation
Percentage of exercise price per share of stock options over fair market value of common share	100.00%
2014 Equity Incentive Plan | Maximum
Share-Based Compensation
Stock option term	P10Y
2014 Equity Incentive Plan | Employees and directors
Share-Based Compensation
Vesting period (in years)	3 years
Stock option granted	422,382	0
Share-based compensation expense	$ 1,153	$ 432
2014 Equity Incentive Plan | Non-employees
Share-Based Compensation
Vesting period (in years)	3 years
Stock option granted	58,537	0
Share-based compensation expense	$ 733	$ 255

Share-Based Compensation - Stoc

Share-Based Compensation - Stock Option Valuation (Details) - $ / shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Jul. 31, 2016	Feb. 29, 2016
Stock Option Valuation
Stock option granted		0
Fair value of common share			$ 7.70	$ 7
2014 Equity Incentive Plan
Stock Option Valuation
Stock option granted	480,919
2014 Equity Incentive Plan | Employees and directors
Stock Option Valuation
Stock option granted	422,382	0
Risk-free interest rate	1.96%
Expected term (in years)	5 years 6 months 4 days
Expected volatility	70.46%
Expected dividend yield	0.00%
Exercise price	$ 9.38
Fair value of common share	$ 8.68
2014 Equity Incentive Plan | Non-employees
Stock Option Valuation
Stock option granted	58,537	0
Risk-free interest rate	2.45%
Expected term (in years)	10 years
Expected volatility	69.98%
Expected dividend yield	0.00%
Exercise price	$ 9.29
Fair value of common share	$ 8.68

Share-Based Compensation - St52

Share-Based Compensation - Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Number of shares
Granted		0
Additional disclosure
Weighted average grant-date fair value per share	$ 5.57
Total fair value of options vested	$ 1,034	$ 0
2014 Equity Incentive Plan
Number of shares
Outstanding at the beginning	3,864,425
Granted	480,919
Outstanding at the end	4,345,344		3,864,425
Options exercisable as of March 31, 2017	2,442,114
Options unvested as of March 31, 2017	1,903,230
Weighted Average Exercise Price
Outstanding at the beginning (in dollars per share)	$ 3.61
Granted (in dollars per share)	9.37
Outstanding at the end (in dollars per share)	4.24		$ 3.61
Options exercisable as of March 31, 2017 (in dollars per share)	3.02
Options unvested as of March 31, 2017 (in dollars per share)	$ 5.81
Additional disclosure
Outstanding average remaining contractual term (in years)	9 years 2 months 5 days		9 years 2 months 16 days
Outstanding aggregate intrinsic value	$ 28,578		$ 15,991
Options exercisable as of March 31, 2017 (in years)	8 years 2 months 1 day
Options unvested as of March 31, 2017 ( in years)	8 years 9 months 26 days
Options exercisable as of March 31, 2017 (in dollars)	$ 19,051
Options unvested as of March 31, 2017 (in dollars)	$ 9,527

Share-Based Compensation (Detai

Share-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Share-Based Compensation
Share-based compensation expense	$ 1,886	$ 687
Total unrecognized compensation cost	$ 7,685
Weighted average period of unrecognized compensation cost	2 years 4 days
Research and development expenses
Share-Based Compensation
Share-based compensation expense	$ 999	335
General and administrative expenses
Share-Based Compensation
Share-based compensation expense	$ 887	$ 352

License Agreements - Yale Agree

License Agreements - Yale Agreement (Details) $ in Thousands	1 Months Ended		3 Months Ended
	Feb. 29, 2016USD ($)shares	Sep. 30, 2013USD ($)itemshares	Mar. 31, 2017USD ($)	Jul. 31, 2016USD ($)shares	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)	Jul. 31, 2015USD ($)	Jan. 31, 2014USD ($)
License agreements
Issuance of common shares | shares	429,000			1,090,500
Investment	$ 2,980			$ 8,299	$ 3,003
Research and development			$ 10,740		2,370
Yale Agreement | Collaborative arrangement
License agreements
Issuance of common shares | shares		250,000
Number of financings with institutional investors | item		2
Fair value of obligation		$ 0	223			$ 512	$ 0	$ 0
Percentage of dollar value of all initial and future consideration		5
Consideration payable upon change-of-control event		$ 1,500
Other expense for change in the fair value of the derivative liability			289		$ 3
Fair value of derivative liability		0	223			$ 512	$ 0	$ 0
Minimum milestone payment to be paid		$ 1,000
Notice period to Yale to terminate the Yale Agreement		90 days
Last patent right expiration period		10 years
Research and development			$ 3
Yale Agreement | Collaborative arrangement | Maximum
License agreements
Right to purchase securities in specified future equity offering (as a percent)		10
Company's fully diluted common shares outstanding (as a percent)		1
Milestone payment to be paid		$ 2,000
Extension of due diligence requirements		1 year
Amount of payment subject to due diligence extension		$ 150
Yale Agreement | Collaborative arrangement | Minimum
License agreements
Investment		$ 3,500
Yale's ownership percentage		1.00%					1.00%	1.00%

License Agreements - MGH Agreem

License Agreements - MGH Agreement (Details) - MGH Agreement - Collaborative arrangement $ in Thousands	1 Months Ended
	Sep. 30, 2014USD ($)
Maximum
License agreements
License maintenance fees	$ 50
Milestone payment to be paid	750
Commercial milestone payment to be paid	$ 2,500
Extension of due diligence requirements	1 year
Amount of payment subject to due diligence extension	$ 300
Minimum
License agreements
License maintenance fees	$ 30

License Agreements - ALS Biopha

License Agreements - ALS Biopharma Agreement (Details) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended			12 Months Ended
	Feb. 29, 2016shares	Aug. 31, 2015USD ($)item$ / sharesshares	Mar. 31, 2017USD ($)	Jul. 31, 2016shares	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)
License agreements
Issuance of common shares | shares	429,000			1,090,500
Research and development | $			$ 10,740		$ 2,370
ALS Biopharma Agreement | Product related collaborative arrangements
License agreements
Number of prodrugs of glutamate modulating agents | item		300
Milestone payment to be paid | $		$ 3,000
Milestone payment to be paid for subsequently developed products | $		$ 1,000
Issuance of common shares | shares		50,000
Number of claims | item		1
Research and development | $			$ 0			$ 375
Common stock warrants issued, immediately exercisable | ALS Biopharma Agreement | Product related collaborative arrangements
License agreements
Issuance of common shares | shares		275,000
Exercise price per share | $ / shares		$ 5.60
Common stock warrants issued, exercisable upon filing drug application | ALS Biopharma Agreement | Product related collaborative arrangements
License agreements
Issuance of common shares | shares		325,000
Exercise price per share | $ / shares		$ 5.60

License Agreements - Rutger Agr

License Agreements - Rutger Agreement (Details) $ in Thousands	1 Months Ended	3 Months Ended
	Jun. 30, 2016USD ($)	Mar. 31, 2017USD ($)	Mar. 31, 2016USD ($)
License agreements
Research and development		$ 10,740	$ 2,370
Rutgers Agreement | Collaborative arrangement
License agreements
License Costs	$ 75
Number of years the Company is required to pay Rutgers annual license maintenance fees	5 years
Annual license maintenance fees after execution of the agreement	$ 25
Change of control fee	0.3
Consideration payable upon change-of-control event	$ 100
Fair value of derivative liability	$ 0	0
Last patent right expiration period	10 years
Research and development		$ 0
Rutgers Agreement | Collaborative arrangement | Maximum
License agreements
Milestone payment to be paid	$ 825
Extension of due diligence requirements	1 year
Amount of payment subject to due diligence extension	$ 500
Rutgers Agreement | Collaborative arrangement | Minimum
License agreements
Guaranteed royalties	$ 100

License Agreements - BMS Agreem

License Agreements - BMS Agreement (Details) $ / shares in Units, $ in Thousands	1 Months Ended			3 Months Ended
	May 31, 2017shares	Jul. 31, 2016USD ($)item$ / shares	Feb. 29, 2016$ / sharesshares	Mar. 31, 2017USD ($)	Jul. 31, 2016USD ($)$ / sharesshares	Mar. 31, 2016USD ($)
License agreements
Net proceeds				$ 40,000
Fair value of common share | $ / shares		$ 7.70	$ 7		$ 7.70
Issuance of common shares | shares			429,000		1,090,500
Research and development				10,740		$ 2,370
BMS Agreement | Product related collaborative arrangements
License agreements
Common shares value issued		$ 12,500
Fair value of common share | $ / shares		$ 9.2911			$ 9.2911
Other expense for change in the fair value of the derivative liability				1,875
Increase in the fair value of the liability		$ 15,938			$ 15,938
Issuance of common shares | shares	1,345,374
Research and development				$ 0
BMS Agreement | Product related collaborative arrangements | Maximum
License agreements
Milestone payment to be paid		127,500
Milestone payment to be paid for any product other than rimegepant		74,500
Commercial milestone payment to be paid		$ 150,000
Right to purchase shares fully diluted (as a percent)		8			8
BMS Agreement | Product related collaborative arrangements | Minimum
License agreements
Number of licensed products | item		1
Net proceeds		$ 30,000
Minimum investment in equity		$ 22,000			$ 22,000

License Agreements - AstoZeneca

License Agreements - AstoZeneca Agreement (Details) $ / shares in Units, $ in Thousands	1 Months Ended			3 Months Ended
	May 31, 2017shares	Oct. 31, 2016USD ($)$ / sharesshares	Feb. 29, 2016$ / sharesshares	Mar. 31, 2017USD ($)	Jul. 31, 2016$ / sharesshares	Mar. 31, 2016USD ($)
License agreements
Expiration period based on country by country basis after first commercial sale (in years)		10 years
Fair value of common share | $ / shares			$ 7		$ 7.70
Issuance of common shares | shares			429,000		1,090,500
Research and development				$ 10,740		$ 2,370
AstraZeneca | Product related collaborative arrangements
License agreements
Common stock value agreed to issue		$ 10,000
Common shares value issued		$ 5,000
Percentage of shares to be issued upon closing of the transaction		50
Percentage of remaining shares to be issued after contractual events		50
Fair value of common share | $ / shares		$ 9.2911
Preferred stock issued and sold | shares		538,150
Aggregate fair value		$ 5
Other expense for change in the fair value of the derivative liability				1,500
Reclassification of contingent equity to the carrying value		5
Fair value of derivative liability				6,375
Issuance of common shares | shares	538,149
Research and development				$ 0
AstraZeneca | Product related collaborative arrangements | Maximum
License agreements
Milestone payment to be paid		30,000
Milestone payment to be paid for any product other than Rett syndrome		60,000
Commercial milestone payment to be paid		$ 120,000
Right to purchase shares fully diluted (as a percent)		8
AstraZeneca | Product related collaborative arrangements | Minimum
License agreements
Minimum investment in equity		$ 30,000

License Agreements - Catalent A

License Agreements - Catalent Agreement (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2017	Mar. 31, 2016
License agreements
Research and development		$ 10,740	$ 2,370
Catalent | Collaborative arrangement
License agreements
Last patent right expiration period	10 years
Automatic extension period	1 year
Research and development		$ 0	$ 0
Catalent | Collaborative arrangement | Maximum
License agreements
Milestone payment to be paid	$ 1,575

Net Loss per Share (Details)

Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Numerator:
Net Loss	$ (18,753)	$ (2,986)
Net loss attributable to non-controlling interests		35
Accretion of beneficial conversion feature on series A preferred shares	(4,000)
Net loss attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd.	$ (22,753)	$ (2,951)
Denominator:
Weighted average common shares outstanding-basic and diluted	13,088,861	11,776,429
Net loss per share attributable to common share holders of Biohaven Pharmaceutical Holding Company Ltd.-basic and diluted	$ (1.74)	$ (0.25)

Net Loss per Share - Antidiluti

Net Loss per Share - Antidilutive Securities Excluded from EPS (Details) - shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Securities excluded from computation of diluted net loss per share
Anti-dilutive securities excluded from calculation of diluted net loss per share	5,160,344	3,522,500
Options to purchase common shares | Common Shares
Securities excluded from computation of diluted net loss per share
Anti-dilutive securities excluded from calculation of diluted net loss per share	4,345,344	3,247,500
Warrants to purchase common shares
Securities excluded from computation of diluted net loss per share
Anti-dilutive securities excluded from calculation of diluted net loss per share	815,000	275,000

Commitments and Contingencies -

Commitments and Contingencies - Lease Agreement (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)
Future minimum payments under operating leases
Rent expense	$ 16
Future minimum lease payments due in 2017 (remaining nine months)	30
Future minimum lease payments due in 2018	$ 35

Commitments and Contingencies64

Commitments and Contingencies - Research Commitments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Contingencies and commitments
Minimum payments under CRO preclinical studies and clinical trials	$ 10,740	$ 2,370
Research Commitments with CROs | Minimum
Contingencies and commitments
Minimum payments under CRO preclinical studies and clinical trials	$ 12,473

Related Party Transactions (Det

Related Party Transactions (Details)	Jan. 26, 2017$ / sharesshares	Dec. 31, 2016USD ($)	Aug. 29, 2016director$ / sharesshares	Sep. 30, 2013USD ($)itemshares	Mar. 31, 2017USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)item
Related Party Transactions
Common stock value | $		$ 19,944,000			$ 20,296,000		$ 19,944,000
Chief Executive Officer | License Agreement with Yale
Related Party Transactions
Number of inventors of the patents licensed from Yale | item				1
Common shares issued | shares				250,000
Percent of Company's outstanding equity fully diluted				5.10%
Common stock value | $				$ 152,000
Payments to related party | $		$ 0			0		$ 0
Recognized research and development expenses | $					$ 0	$ 8,000
Shareholders and members of the Board of Directors | Guarantor and Co-Guarantor Warrants | Guarantor and Co-Guarantor Warrants
Related Party Transactions
Common shares issued | shares	107,500
Exercise price of warrants (per share) | $ / shares	$ 9.2911
Equity Investment | Kleo Pharmaceuticals, Inc.
Related Party Transactions
Shares of Kleo common stock purchased | shares			3,000,000
Price per share | $ / shares			$ 1
Additional shares of Kleo common stock purchased | shares			5,500,000
Number to designate to Kleo's board of directors | director			2
Shares of Kleo common stock purchased from Chief Executive Officer | shares			500,000
Ownership percentage					27.90%
Majority Shareholder | Biohaven Pharmaceuticals, Inc.
Related Party Transactions
Number of founders | item							3
Equity share percentage owned by each founders		33.33%					33.33%
Ownership interest acquired		100.00%					100.00%
Aggregate purchase consideration | $		$ 595,000					$ 595,000

Acquisition of Biohaven Pharm66

Acquisition of Biohaven Pharmaceuticals Inc (Details) $ in Thousands	Dec. 31, 2016USD ($)	Mar. 31, 2017installment	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)item
Acquisition of Biohaven Pharmaceuticals, Inc.
Net loss attributable to non-controlling interests			$ 35
Biohaven Pharmaceuticals, Inc. | Majority Shareholder
Acquisition of Biohaven Pharmaceuticals, Inc.
Ownership interest acquired	100.00%			100.00%
Aggregate purchase consideration	$ 595
Number of founders | item				3
Equity share percentage owned by each founders	33.33%			33.33%
Number of installments in which notes are payable | installment		5
Number of interest only related party notes payable installments | installment		4
Interest rate of notes		4.50%
Carrying value of non-controlling interest derecognized	$ 86			$ 86
Reduction to additional paid-in capital				$ 509
Net loss attributable to non-controlling interests			$ 35

Subsequent Events (Details)

Subsequent Events (Details) - USD ($)	May 11, 2017	May 09, 2017	May 03, 2017	Jun. 30, 2017	May 31, 2017	Oct. 31, 2016	Jul. 31, 2016	Feb. 29, 2016	Sep. 30, 2013	Mar. 31, 2017	Jul. 31, 2016	Mar. 31, 2016	Apr. 30, 2017	Apr. 21, 2017	Dec. 31, 2016	Aug. 29, 2016
Subsequent Events
Number of shares authorized										38,000,000					38,000,000
Common stock, par value (in dollars per share)										$ 0					$ 0
Preferred stock, shares authorized										11,242,172					11,242,172
Preferred stock, par value (in dollars per share)										$ 0					$ 0
Issuance of common shares								429,000			1,090,500
Issuance price per share							$ 7.70	$ 7			$ 7.70
Net proceeds from issuance of shares, after deducting underwriting discounts and commissions and other offering expenses					$ 176,367,000
Other offering expenses								$ 23,000		$ 2,049,000	$ 97,000	$ 23,000
Cash payment for purchase of equity method investment										$ 1,624,000
2014 Equity Incentive Plan
Subsequent Events
Number of shares granted										553,886		1,034,805
Subsequent Event
Subsequent Events
Number of shares authorized	200,000,000												50,000,000	50,000,000
Common stock, par value (in dollars per share)	$ 0
Preferred stock, shares authorized	10,000,000
Preferred stock, par value (in dollars per share)	$ 0
Aggregate net proceeds from the IPO and underwriters issuance	$ 176,367,000
Subsequent Event | Initial public offering
Subsequent Events
Issuance of common shares		9,900,000
Issuance price per share		$ 17
Net proceeds from issuance of shares, after deducting underwriting discounts and commissions and other offering expenses		$ 152,889,000
Other offering expenses		3,630,000
Underwriting discounts and commissions		$ 11,781,000
Convertible preferred stock converted into shares of common stock		9,358,560
Remaining unamortized portion of BCF reclassified to additional paid-in-capital		$ 8,006,000
Fair value of contingent equity liabilities					32,020,000
Repayment of principal amount to related party					595,000
Repayment of interest amount to related party					$ 9,000
Subsequent Event | Over allotment option
Subsequent Events
Issuance of common shares	1,485,000
Net proceeds from issuance of shares, after deducting underwriting discounts and commissions and other offering expenses	$ 23,478,000
Aggregate net proceeds from the IPO and underwriters issuance	176,367,000
Net proceeds from underwriting	23,478,000
Underwriting discounts and commissions	$ 1,767,000
Subsequent Event | Over allotment option | BMS and AstraZenca
Subsequent Events
Issuance of common shares	1,883,523	1,883,523
Common shares value issued	$ 0
Subsequent Event | 2017 Equity Incentive Plan
Subsequent Events
Number of shares reserved for issuance			7,611,971
Number of shares granted			2,712,741
Percentage of common stock issued that can be increased			4.00%
Subsequent Event | 2014 Equity Incentive Plan
Subsequent Events
Number of shares granted			372
Subsequent Event | 2017 Employee Share Purchase Plan
Subsequent Events
Number of shares reserved for issuance			339,139
Minimum number of issued shares that can be increased			600,000
Percentage of common stock issued that can be increased			1.00%
Product related collaborative arrangements | BMS Agreement
Subsequent Events
Issuance of common shares					1,345,374
Issuance price per share							$ 9.2911				$ 9.2911
Common shares value issued							$ 12,500,000
Product related collaborative arrangements | AstraZeneca
Subsequent Events
Issuance of common shares					538,149
Issuance price per share						$ 9.2911
Common shares value issued						$ 5,000,000
Product related collaborative arrangements | Subsequent Event | Initial public offering | BMS Agreement
Subsequent Events
Issuance of common shares					1,345,374
Product related collaborative arrangements | Subsequent Event | Initial public offering | AstraZeneca
Subsequent Events
Issuance of common shares					538,149
Collaborative arrangement | Yale Agreement
Subsequent Events
Issuance of common shares									250,000
Kleo
Subsequent Events
Shares purchased in equal tranches										1,375,000						1,375,000
Cash payment for purchase of equity method investment										$ 1,976,000
Kleo | Subsequent Event
Subsequent Events
Shares purchased in equal tranches				1,375,000
Cash payment for purchase of equity method investment				$ 1,375,000