Biohaven Pharmaceutical Holding 10-Q 9 Aug 21 2021 Q2 Quarterly report Financial data

COVER

COVER - shares	6 Months Ended
	Jun. 30, 2021	Aug. 05, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2021
Document Transition Report	false
Entity File Number	001-38080
Entity Registrant Name	Biohaven Pharmaceutical Holding Company Ltd.
Entity Incorporation, State or Country Code	D8
Entity Address, Address Line One	c/o Biohaven Pharmaceuticals, Inc.
Entity Address, Address Line Two	215 Church Street
Entity Address, City or Town	New Haven
Entity Address, State or Province	CT
Entity Address, Postal Zip Code	06510
City Area Code	203
Local Phone Number	404-0410
Title of 12(b) Security	Common Shares, no par value
Trading Symbol	BHVN
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		65,401,228
Entity Central Index Key	0001689813
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 306,267	$ 132,149
Marketable securities	59,840	223,185
Trade receivable, net	168,637	120,111
Inventory	64,058	39,563
Prepaid Expense, Current	48,871	76,682
Other prepaid expenses	18,907	11,716
Total current assets	666,580	603,406
Property and equipment, net	10,885	9,340
Equity method investment	0	1,176
Intangible assets, net	57,501	39,087
Other assets	110,927	33,966
Total assets	845,893	686,975
Current liabilities:
Accounts payable	60,002	48,476
Accrued expenses and other current liabilities	276,630	166,630
Current portion of mandatorily redeemable preferred shares	62,500	62,500
Total current liabilities	399,132	277,606
Long-term debt	274,138	267,458
Liability related to sale of future royalties, net	347,384	328,350
Mandatorily redeemable preferred shares, net	133,091	111,591
Derivative liability	15,890	14,190
Obligation to perform R&D services	55,353	932
Other long-term liabilities	17,501	19,037
Total liabilities	1,242,489	1,019,164
Commitments and contingencies
Contingently redeemable non-controlling interests	60,000	60,000
Shareholders’ deficit:
Common shares, no par value; 200,000,000 shares authorized as of June 30, 2021 and December 31, 2020; 65,240,458 and 60,436,876 shares issued and outstanding as of June 30, 2021 and December 31, 2020, respectively	1,618,194	1,249,547
Additional paid-in capital	142,405	98,938
Accumulated other comprehensive income	280	314
Accumulated deficit	(2,214,756)	(1,739,169)
Total shareholders’ deficit attributable to Biohaven Pharmaceutical Holding Company Ltd.	(453,877)	(390,370)
Non-controlling interests in consolidated subsidiaries	(2,719)	(1,819)
Total shareholders' deficit	(456,596)	(392,189)
Total liabilities and shareholders’ deficit	$ 845,893	$ 686,975

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Common shares, par value (in dollars per share)	$ 0	$ 0
Common shares, authorized (shares)	200,000,000	200,000,000
Common shares, issued (shares)	65,240,458	60,436,876
Common shares, outstanding (shares)	65,240,458	60,436,876

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
Product revenue, net	$ 92,933	$ 9,698	$ 136,756	$ 10,849
Product revenue, type	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Cost of goods sold	$ 17,339	$ 3,058	$ 30,201	$ 3,482
Cost of goods sold, type	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Gross profit	$ 75,594	$ 6,640	$ 106,555	$ 7,367
Operating expenses:
Research and development expense	77,428	42,425	184,539	98,495
Selling, general and administrative	170,057	124,802	329,580	220,403
Total operating expenses	247,485	167,227	514,119	318,898
Loss from operations	(171,891)	(160,587)	(407,564)	(311,531)
Other income (expense):
Interest expense	(7,836)	(172)	(15,567)	(227)
Interest expense on mandatorily redeemable preferred shares	(8,042)	(6,993)	(15,985)	(12,554)
Interest expense on liability related to sale of future royalties	(14,499)	(11,570)	(28,007)	(19,995)
Change in fair value of derivatives	(1,490)	650	(1,700)	(5,131)
Gain (loss) from equity method investment	0	(1,485)	5,261	(2,865)
Other expense, net	(3,051)	(119)	(4,751)	(216)
Total other income (expense), net	(34,918)	(19,689)	(60,749)	(40,988)
Loss before provision for income taxes	(206,809)	(180,276)	(468,313)	(352,519)
Provision for income taxes	4,350	658	8,174	1,352
Net loss	(211,159)	(180,934)	(476,487)	(353,871)
Less: Net loss attributable to non-controlling interests	(540)	0	(900)	0
Net loss attributable to Biohaven Pharmaceutical Holding Company Ltd.	$ (210,619)	$ (180,934)	$ (475,587)	$ (353,871)
Net loss per share attributable to Biohaven Pharmaceutical Holding Company Ltd - basic (in dollars per share)	$ (3.23)	$ (3.08)	$ (7.48)	$ (6.15)
Net loss per share attributable to Biohaven Pharmaceutical Holding Company Ltd - diluted (in dollars per share)	$ (3.23)	$ (3.08)	$ (7.48)	$ (6.15)
Weighted average common shares outstanding - basic (shares)	65,112,179	58,742,329	63,584,932	57,577,384
Weighted average common shares outstanding - diluted (shares)	65,112,179	58,742,329	63,584,932	57,577,384
Comprehensive loss:
Net loss	$ (211,159)	$ (180,934)	$ (476,487)	$ (353,871)
Other comprehensive loss, net of tax	(129)	0	(34)	0
Comprehensive loss	(211,288)	(180,934)	(476,521)	(353,871)
Less: comprehensive loss attributable to non-controlling interests	(540)	0	(900)	0
Comprehensive loss attributable to Biohaven Pharmaceutical Holding Company Ltd.	$ (210,748)	$ (180,934)	$ (475,621)	$ (353,871)

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities:
Net loss attributable to Biohaven Pharmaceutical Holding Company Ltd.	$ (475,587)	$ (353,871)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash share-based compensation expense	74,312	28,641
Interest expense on mandatorily redeemable preferred shares	15,985	12,554
Interest expense on liability related to sale of future royalties	28,007	19,995
Interest expense paid-in-kind on long-term debt	5,649	0
Issuance of common shares as payment for license and consulting agreements	4,243	0
Change in fair value of derivatives	1,700	5,131
(Gain) loss from equity method investment	(5,261)	2,865
Depreciation and amortization	11,278	1,551
Change in obligation to perform R&D services	(10,205)	0
Other non-cash items	2,093	150
Changes in operating assets and liabilities:
Trade receivables, net	(48,526)	(44,796)
Inventories	(19,046)	(6,931)
Prepaid expenses	28,710	(36,626)
Other current assets	(7,051)	2,246
Other assets	(79,832)	17
Accounts payable	5,085	934
Accrued expenses and other current liabilities	63,868	41,543
Other long-term liabilities	(28,138)	62
Net cash used in operating activities	(432,716)	(326,535)
Cash flows from investing activities:
Sales and maturities of marketable securities	162,293	0
Purchases of property and equipment	(1,657)	(1,381)
Payments for leasehold improvements	0	(1,600)
Payments for intangible assets	0	(21,500)
Net cash provided by (used in) investing activities	160,636	(24,481)
Cash flows from financing activities:
Proceeds from issuance of common shares	308,743	283,333
Proceeds from obligation to perform R&D services	100,000	0
Proceeds from the issuance of series B preferred shares	35,170	0
Proceeds from exercise of share options and employee share purchase plan	8,643	14,355
Payment of term loan commitment fee	(3,750)	0
Payment of principal for finance leases	(2,514)	(37)
Payment of term loan	(1,195)	0
Other	1,090	(500)
Net cash provided by financing activities	446,187	297,151
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(189)	0
Net increase (decrease) in cash, cash equivalents and restricted cash	173,918	(53,865)
Cash, cash equivalents and restricted cash at beginning of period	134,231	317,727
Cash, cash equivalents and restricted cash at end of period	$ 308,149	$ 263,862

Nature of the Business

Nature of the Business	6 Months Ended
	Jun. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business	Nature of the Business Biohaven Pharmaceutical Holding Company Ltd. (“we,” “us”, "our," "Biohaven" or the “Company”) was incorporated in Tortola, British Virgin Islands in September 2013. We are a biopharmaceutical company with a portfolio of innovative product candidates targeting neurological diseases, including rare disorders. The Company's lead product, NURTEC™ ODT (rimegepant), was approved by the U.S. Food and Drug Administration ("FDA") on February 27, 2020, which became available by prescription in U.S. pharmacies on March 12, 2020, and was approved for the preventive treatment of migraine on May 27, 2021. NURTEC ODT is the first and only calcitonin gene-related peptide ("CGRP") receptor antagonist available in a quick-dissolve orally dissolving tablet ("ODT") formulation that is approved by the FDA for both the acute and preventive treatment of migraine in adults. Our other late-stage product candidates are based on multiple mechanisms — CGRP receptor antagonists, glutamate modulators and myeloperoxidase inhibition—which we believe have the potential to significantly alter existing treatment approaches across a diverse set of neurological indications with high unmet need in both large and orphan indications. The Company is subject to risks and uncertainties common to companies in the biopharmaceutical industry, including, but not limited to, the risks associated with developing product candidates at each stage of non-clinical and clinical development; the challenges associated with gaining regulatory approval of such product candidates; the risks associated with commercializing pharmaceutical products for marketing and sale; the potential for development by third parties of new technological innovations that may compete with the Company’s products; the dependence on key personnel; the challenges of protecting proprietary technology; the need to comply with government regulations; the high costs of drug development; and the uncertainty of being able to secure additional capital when needed to fund operations. Subsequent to its May 2017 initial public offering, the Company has primarily raised funds through sales of equity in private placements and public offerings, sale of revenue participation rights related to future royalties, debt financing and funds received for a research and development obligation. The Company has incurred recurring losses since its inception, had an accumulated deficit as of June 30, 2021, and expects to continue to generate operating losses during the commercial launch of NURTEC ODT for the acute and preventive treatment of migraine. To execute its business plans, the Company will continue to require additional funding to support its continuing operations and pursue its growth strategy. As of August 9, 2021, the issuance date of our condensed consolidated financial statements, the Company expects that its cash, cash equivalents and marketable securities as of June 30, 2021, and the funds available from the Sixth Street Financing Agreement (see Note 14) and Series B Preferred Shares (see Note 8) will be sufficient to fund its current forecast for operating expenses, including commercialization of NURTEC ODT, financial commitments and other cash requirements for more than one year. The Company may need to raise additional capital until it is profitable. If no additional capital is raised through either public or private equity financings, debt financings, strategic relationships, alliances and licensing agreements, or a combination thereof, the Company may delay, limit or reduce discretionary spending in areas related to research and development activities and other general and administrative expenses in order to fund its operating costs and working capital needs.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Our significant accounting policies are described in Note 2 of the notes to the consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2020 (the "2020 Form 10-K"). Updates to our accounting policies, including impacts from the adoption of new accounting standards, are discussed below in this Note 2. Basis of Presentation The accompanying condensed 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 controlled subsidiaries after elimination of all significant intercompany accounts and transactions. Investments in 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 financial statements of our subsidiaries with functional currencies other than the U.S. dollar are translated into U.S. dollars using period-end exchange rates for assets and liabilities, historical exchange rates for shareholders' equity (deficit) and weighted average exchange rates for operating results. Translation gains and losses are included in accumulated other comprehensive income, net of tax, in shareholders' deficit. Foreign currency transaction gains and losses are included in other income (expense) in the condensed consolidated statement of operations and comprehensive loss. Reclassifications Certain items in the prior period’s condensed consolidated financial statements have been reclassified to conform to the current presentation. Use of Estimates The preparation of condensed 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 condensed consolidated financial statements and the reported amounts of income and expenses during the reporting periods. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, revenue recognition, interest expense on liability related to sale of future royalties, valuation of Series B preferred shares forward contracts and income taxes. 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. Inventory The Company values its inventories at the lower-of-cost or net realizable value. The Company determines the cost of its inventories, which includes costs related to products held for sale in the ordinary course of business, products in process of production for such sale and items to be currently consumed in the production of goods to be available for sale, on a first-in, first-out (FIFO) basis. Due to the nature of the Company’s supply chain process, inventory that is owned by the Company, is physically stored at third-party warehouses, logistics providers and contract manufacturers. The Company classifies inventory costs as noncurrent when we expect to utilize the inventory beyond our normal operating cycle and includes these costs in other assets in our condensed consolidated balance sheets. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period, and writes down any excess and obsolete inventories to their net realizable value in the period in which the impairment is first identified. If they occur, such impairment charges are recorded as a component of cost of goods sold in the consolidated statements of operations. The Company capitalizes inventory costs associated with products following regulatory approval when future commercialization is considered probable and the future economic benefit is expected to be realized. Products which may be used in clinical development programs are excluded from inventory and charged to research and development expense in the consolidated statement of operations as incurred. Prior to the initial date regulatory approval is received, costs related to the production of inventory are recorded as research and development expense on the Company’s consolidated statements of operations in the period incurred. Following FDA approval of NURTEC ODT on February 27, 2020, the Company subsequently began capitalizing costs related to inventory manufacturing. Acquisitions Our condensed consolidated financial statements include the operations of acquired businesses after the completion of the acquisitions. We account for acquired businesses using the acquisition method of accounting, which requires, among other things, that most assets acquired and liabilities assumed be recognized at their estimated fair values as of the acquisition date and that the fair value of acquired In-Process Research and Development ("IPR&D") be recorded on the balance sheet. Transaction costs are expensed as incurred. Any excess of the consideration transferred over the assigned values of the net assets acquired is recorded as goodwill. Contingent consideration in a business acquisition is included as part of the consideration transferred and is recognized at fair value as of the acquisition date. Fair value is generally estimated by using a probability-weighted discounted cash flow approach. Acquired In-Process Research and Development IPR&D that the Company acquires in conjunction with the acquisition of a business represents the fair value assigned to incomplete research projects which, at the time of acquisition, have not reached technological feasibility. The amounts are capitalized and are accounted for as indefinite-lived intangible assets, subject to impairment testing until completion or abandonment of the projects. Upon successful completion of each project, the Company will make a determination as to the then-useful life of the intangible asset, generally determined by the period in which the substantial majority of the cash flows are expected to be generated, and begin amortization. The Company evaluates IPR&D for impairment at least annually, or more frequently if impairment indicators exist, by performing a quantitative test that compares the fair value of the IPR&D intangible asset with its carrying value. If the fair value is less than the carrying amount, an impairment loss is recognized in operating results. Obligation to Perform Research and Development Services The Company accounts for obligations to perform Research and Development ("R&D") services by recording the consideration received as a liability, which then is recognized in the condensed consolidated statement of operations and comprehensive loss as an offset to R&D expense using the percentage completion method. The percentage complete is determined based on incurred R&D costs as a percent of the total forecasted costs of the contractual R&D commitment. Unaudited Interim Condensed Consolidated Financial Information The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America for interim financial information. The accompanying unaudited condensed consolidated financial statements do not include all of the information and footnotes required by accounting principles generally accepted in the United States of America for complete consolidated financial statements. The accompanying year-end condensed consolidated balance sheet was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America. The unaudited interim condensed 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 June 30, 2021 and the results of its operations for the three and six months ended June 30, 2021 and 2020 and its cash flows for the six months ended June 30, 2021 and 2020. The results for the three and six months ended June 30, 2021 are not necessarily indicative of results to be expected for the year ending December 31, 2021, any other interim periods or any future year or period. The financial information included herein should be read in conjunction with the financial statements and notes in the Company's Annual Report on Form 10-K for the year ended December 31, 2020. Recently Adopted Accounting Pronouncements Effective January 1, 2021, the Company adopted ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes ("ASU 2019-12"). This ASU simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740. The amendments also improve consistent application of and simplify GAAP for other areas of Topic 740 by clarifying and amending existing guidance. The adoption of ASU 2019-12 did not have a material impact on the Company's condensed consolidated financial statements. Future Adoption of New Accounting Pronouncements In August 2020 the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity . The update addresses issues identified as a result of the complexity associated with applying GAAP for certain financial instruments with characteristics of liabilities and equity. The amendments in ASU 2020-06 are effective for fiscal years beginning after December 15, 2021, with early adoption permitted, but no earlier than fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. Adoption of the standard requires changes to be made through either a modified retrospective method of transition or a fully retrospective method. In applying the modified retrospective method, the updated guidance is applied to transactions outstanding as of the beginning of the fiscal year in which the amendments are adopted. The Company is currently evaluating the impact that the adoption of ASU 2020-06 will have on its condensed consolidated financial statements. In January 2021 the FASB issued ASU No. 2021-01, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting, providing temporary guidance to ease the burden in accounting for reference rate reform primarily resulting from the discontinuation of LIBOR, which is currently expected to occur in mid-2023 for legacy contracts. The amendments in 2021-01 are elective immediately and apply to all entities that have contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued. The Company is currently evaluating the impact that the adoption of ASU 2021-01 will have on its condensed consolidated financial statements. In May 2021 the FASB issued ASU No. 2021-04, Earnings Per Share (Topic 260), Debt—Modifications and Extinguishments (Subtopic 470-50), Compensation—Stock Compensation (Topic 718), and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Issuer’s Accounting for Certain Modifications or Exchanges of Freestanding Equity-Classified Written Call Options (a consensus of the FASB Emerging Issues Task Force), which provides guidance on modifications or exchanges of a freestanding equity-classified written call option that is not within the scope of another topic. An entity should treat a modification of the terms or conditions or an exchange of a freestanding equity-classified written call option that remains equity classified after modification or exchange as an exchange of the original instrument for a new instrument, and provides further guidance on measuring the effect of a modification or an exchange of a freestanding equity-classified written call option that remains equity classified after modification or exchange. ASU 2021-04 also provides guidance on the recognition of the effect of a modification or an exchange of a freestanding equity-classified written call option that remains equity classified after modification or exchange on the basis of the substance of the transaction, in the same manner as if cash had been paid as consideration. The guidance is applied prospectively and is effective for all entities for fiscal years beginning after 15 December 2021, and interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the impact that the adoption of ASU 2021-04 will have on the condensed consolidated financial statements. The effect will largely depend on the terms of written call options or financings issued or modified in the future.

Marketable Securities

Marketable Securities	6 Months Ended
	Jun. 30, 2021
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	Marketable Securities The amortized cost, gross unrealized holding gains, gross unrealized holding losses and fair value of available-for-sale debt securities by type of security at June 30, 2021 was as follows: Amortized Cost Allowance for Credit Losses Net Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Corporate bonds U.S. $ 46,172 $ — $ 46,172 $ 35 $ (2) $ 46,205 Foreign 13,637 — 13,637 — (2) 13,635 Total $ 59,809 $ — $ 59,809 $ 35 $ (4) $ 59,840 The amortized cost, gross unrealized holding gains, gross unrealized holding losses and fair value of available-for-sale debt securities by type of security at December 31, 2020 was as follows: Amortized Cost Allowance for Credit Losses Net Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Corporate bonds U.S. $ 185,989 $ — $ 185,989 $ 1 $ (106) $ 185,884 Foreign 37,321 — 37,321 1 (21) 37,301 Total $ 223,310 $ — $ 223,310 $ 2 $ (127) $ 223,185 The Company had 9 and 47 available-for-sale debt securities in an unrealized loss position, with an aggregate fair value of $31,387 and $212,378, as of June 30, 2021 and December 31, 2020, respectively. As of June 30, 2021, the Company did not intend to sell these securities, and did not believe it was more likely than not that it would be required to sell these securities prior to the anticipated recovery of their amortized cost basis. We did not have any investments in a continuous unrealized loss position for more than twelve months as of June 30, 2021 and December 31, 2020. The fair values of debt securities available-for-sale by classification in the condensed consolidated balance sheets were as follows: June 30, 2021 December 31, 2020 Marketable securities $ 59,840 $ 223,185 The net amortized cost and fair value of debt securities available-for-sale at June 30, 2021 are shown below by contractual maturity. Actual maturities may differ from contractual maturities because securities may be restructured, called or prepaid, or the Company intends to sell a security prior to maturity. Net Amortized Cost Fair Value Due to mature: Less than one year $ 59,809 $ 59,840 Net Investment Income Sources of net investment income included in other income (expense) in the condensed consolidated statements of operations and comprehensive loss for the three and six months ended June 30, 2021 were as follows: Three Months Ended June 30, 2021 Six Months Ended June 30, 2021 Gross investment income from debt securities available-for-sale $ 89 $ 161 Investment expenses (24) (76) Net investment income (excluding net realized capital gains or losses) 65 85 Net realized capital gains (losses) — 19 Net investment income $ 65 $ 104 The Company had no net investment income during the three and six months ended June 30, 2020.

Fair Value of Financial Assets

Fair Value of Financial Assets and Liabilities	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value of Financial Assets and Liabilities	Fair Value of Financial Assets and Liabilities The preparation of the Company’s condensed consolidated financial statements in accordance with GAAP requires certain assets and liabilities to be reflected at their fair value and others to be reflected on another basis, such as an adjusted historical cost basis. In this note, the Company provides details on the fair value of financial assets and liabilities and how it determines those fair values. Financial Instruments Measured at Fair Value on the Condensed Consolidated Balance Sheets 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. For a description of the methods and assumptions that are used to estimate the fair value and determine the fair value hierarchy classification of each class of financial instrument, see (Note 4) “Fair Value of Financial Assets and Liabilities” in the 2020 Form 10-K. Financial assets and liabilities measured at fair value on a recurring basis on the condensed consolidated balance sheet at June 30, 2021 and December 31, 2020 were as follows: Fair Value Measurement as of June 30, 2021 Using: Balance Sheet Classification Type of Instrument Level 1 Level 2 Level 3 Total Assets: Cash equivalents Money market funds $ 145,462 $ — $ — $ 145,462 Marketable securities U.S. corporate bonds — 46,205 — 46,205 Marketable securities Foreign corporate bonds — 13,635 — 13,635 Total assets $ 145,462 $ 59,840 $ — $ 205,302 Liabilities: Series B preferred shares forward contracts $ — $ — $ 15,890 $ 15,890 Contingent value right liability — — 1,457 1,457 Total liabilities $ — $ — $ 17,347 $ 17,347 Fair Value Measurement as of December 31, 2020 Using: Balance Sheet Classification Type of Instrument Level 1 Level 2 Level 3 Total Assets: Cash equivalents Money market funds $ 6,858 $ — $ — $ 6,858 Marketable securities U.S. corporate bonds — 185,884 — 185,884 Marketable securities Foreign corporate bonds — 37,301 — 37,301 Total assets $ 6,858 $ 223,185 $ — $ 230,043 Liabilities: Series B preferred shares forward contracts $ — $ — $ 14,190 $ 14,190 Total liabilities $ — $ — $ 14,190 $ 14,190 There were no securities transferred between Level 1, 2 and 3 during the six months ended June 30, 2021 and 2020. • Series B Preferred Shares Forward Contracts The following table provides a roll forward of the aggregate fair value of the Company's Series B Preferred Shares Forward Contracts for which fair value is determined by Level 3 inputs for the six months ended June 30, 2021: Forward Contracts Balance at December 31, 2020 $ 14,190 Change in fair value 1,700 Balance at June 30, 2021 $ 15,890 The Company had no Series B Preferred Shares Forward Contracts for the six months ended June 30, 2020. • Contingent Value Right Liability On January 4, 2021, the Company acquired Kleo Pharmaceuticals, Inc. (“Kleo”) (see Note 6). Included in the purchase consideration transferred was a contingent value right to receive one dollar in cash for each Kleo share if certain specified Kleo biopharmaceutical products or product candidates receive the approval of the FDA prior to the expiration of 30 months following the effective time of the transaction. The maximum amount payable pursuant to the contingent value right is approximately $17,300, and the fair value of the contingent value right was $1,457 as of the acquisition date. The Company recorded the contingent value right in other long-term liabilities on the condensed consolidated balance sheets. The fair value of the contingent value right was determined based on significant inputs not observable in the market, which represents a Level 3 measurement within the fair value hierarchy. The Company used a discounted cash flow approach to value the contingent value right liability. As inputs into the valuation, the Company considered the probability of FDA approval within the 30 month period, which we estimated at approximately 10%, the amount of the payment, and a discount rate of approximately 7% determined using an implied credit spread adjusted based on companies with similar credit risk. There was no material change in fair value of the contingent value right liability during the three and six months ended June 30, 2021. • Series A Preferred Shares Derivative Liability The Company had no Series A preferred shares derivative liability for the six months ended June 30, 2021. The following table provides a roll forward of the aggregate fair value of the Company’s Series A preferred shares derivative liability for which fair value is determined by Level 3 inputs for the six months ended June 30, 2020: Series A Derivative Balance at December 31, 2019 $ 37,690 Change in fair value of derivative liability 5,131 Partial settlement of derivative liability (42,821) Balance at June 30, 2020 $ —

Balance Sheet Components

Balance Sheet Components	6 Months Ended
	Jun. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Components	Balance Sheet Components Restricted Cash Restricted cash included in other current assets in the condensed consolidated balance sheets is primarily employee contributions to the Company's employee share purchase plan held for future purchases of the Company's outstanding shares. Restricted cash included in other assets in the condensed consolidated balance sheets represents collateral held by a bank for a letter of credit ("LOC") issued in connection with the leased office space in Yardley, Pennsylvania. The following represents a reconciliation of cash and cash equivalents in the condensed consolidated balance sheets to total cash, cash equivalents and restricted cash as of June 30, 2021 and December 31, 2020, respectively, in the condensed consolidated statement of cash flows: June 30, 2021 December 31, 2020 Cash and cash equivalents $ 306,267 $ 132,149 Restricted cash (included in other current assets) 1,132 1,082 Restricted cash (included in other assets) 750 1,000 Cash, cash equivalents and restricted cash in the statement of cash flows $ 308,149 $ 134,231 Trade Receivables, Net The Company’s trade accounts receivable consists of amounts due from pharmacy wholesalers in the U.S. (collectively, its "Customers") related to sales of NURTEC ODT and have standard payment terms. For certain Customers, the trade accounts receivable for the Customer is net of distribution service fees, prompt pay discounts and other adjustments. The Company monitors the financial performance and creditworthiness of its Customers so that it can properly assess and respond to changes in their credit profile. The Company reserves against trade accounts receivable for estimated losses that may arise from a Customer’s inability to pay and any amounts determined to be uncollectible are written off against the reserve when it is probable that the receivable will not be collected. The allowance for doubtful accounts, including reserve amounts for estimated credit losses, was immaterial as of June 30, 2021 and December 31, 2020. Inventories Inventories consisted of the following: As of June 30, 2021 As of December 31, 2020 Raw materials $ — $ 931 Work-in-process 94,324 33,266 Finished goods 3,462 5,366 Total inventories $ 97,786 $ 39,563 Less noncurrent inventories (1) 33,728 — Total inventories classified as current $ 64,058 $ 39,563 (1) Included in other assets on the condensed consolidated balance sheets. There are no recoverability issues for these amounts. Prepaid Expenses Prepaid expenses consisted of the following: As of June 30, 2021 As of December 31, 2020 Prepaid clinical trial costs $ 24,108 $ 21,173 Prepaid manufacturing 2,919 36,040 Prepaid commercial costs 19,326 16,448 Other prepaid expenses 2,518 3,021 Prepaid expenses $ 48,871 $ 76,682 Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following: As of June 30, 2021 As of December 31, 2020 Accrued development milestones $ 500 $ 667 Accrued employee compensation and benefits 26,964 29,447 Accrued clinical trial costs 29,972 19,887 Accrued commercialization and other professional fees 27,273 6,336 Accrued sales discounts and allowances 104,668 73,155 Current obligation to perform R&D services 37,466 846 Other accrued expenses and other current liabilities 49,787 36,292 Accrued expenses and other current liabilities $ 276,630 $ 166,630

Business Acquisition

Business Acquisition	6 Months Ended
	Jun. 30, 2021
Business Combination and Asset Acquisition [Abstract]
Business Acquisition	Business Acquisition On January 4, 2021, the Company acquired Kleo Pharmaceuticals, Inc. (“Kleo”). Kleo is a development-stage biopharmaceutical company focused on advancing the field of immunotherapy by developing small molecules that emulate biologics. The transaction was accounted for as the acquisition of a business using the acquisition method of accounting. The total fair value of the consideration transferred was $20,043 which consisted of the issuance of a total of 115,836 common shares of the Company to Kleo stockholders and contingent consideration in the form of a contingent value right to receive one dollar in cash for each Kleo share if certain specified Kleo biopharmaceutical products or product candidates receive the approval of the FDA prior to the expiration of 30 months following the effective time of the transaction. The maximum amount payable pursuant to the contingent value right is approximately $17,300, and the fair value of the contingent value right is $1,457 as of the acquisition date. The transaction also provides for approximately $950 of cash holdbacks to provide for potential indemnification claims and other reserves. Any holdback amounts remaining after the holdback periods will be released to the Kleo stockholders in the form of cash consideration. Prior to the consummation of the transaction, the Company owned approximately 41.9% of the outstanding shares of Kleo and accounted for it as an equity method investment. As part of the transaction, the Company acquired the remainder of the shares of Kleo, and post-transaction the Company owns 100% of the outstanding shares of Kleo. The carrying value of the Company’s investment in Kleo was $1,176 immediately prior to the acquisition date. The Company determined the fair value of the existing interest was $6,437, and recognized a gain from our equity method investment of $5,261 for the six months ended June 30, 2021 on the condensed consolidated statement of operations and comprehensive loss as a result of remeasuring to fair value the existing equity interest in Kleo. In connection with the transaction, we recorded: net working capital of $573; property, plant and equipment of $1,257; intangible assets consisting of in progress research and development assets of $18,400 which include an oncology therapeutic candidate entering Phase I clinical trials, and a COVID-19 therapeutic candidate in the planning stage for clinical development; debt assumed of $1,577; and goodwill of $1,390.

Liability Related to Sale of Fu

Liability Related to Sale of Future Royalties, net	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Liability Related to Sale of Future Royalties, net	Liability Related to Sale of Future Royalties, net 2018 RPI Funding Agreement In June 2018, the Company entered into a funding agreement (the "2018 RPI Funding Agreement") to sell tiered, sales-based royalty rights on global net sales of pharmaceutical products containing the compounds rimegepant or zavegepant (previously known as BHV-3500 and vazegepant) and certain derivative compounds thereof ("Products") to RPI, a Delaware statutory trust. The Company issued to RPI the right to receive certain revenue participation payments, subject to certain reductions, based on the future global net sales of the Products for each calendar quarter during the royalty term contemplated by the 2018 RPI Funding Agreement, in exchange for $100,000 in cash. Concurrent with the 2018 RPI Funding Agreement, the Company entered into a common stock purchase agreement (the "Purchase Agreement") with RPI. Pursuant to the Purchase Agreement, the Company sold 1,111,111 common shares of the Company to RPI at a price of $45.00 per share, for gross proceeds of $50,000. The Company concluded that there were two units of account for the consideration received comprised of the liability related to sale of future royalties and the common shares. The Company allocated the $100,000 from the 2018 RPI Funding Agreement and $50,000 from the Purchase Agreement among the two units of account on a relative fair value basis at the time of the transaction. The Company allocated $106,047 in transaction consideration to the liability, and $43,953 to the common shares. The Company determined the fair value of the common shares based on the closing share price on the transaction date, adjusted for the trading restrictions. The transaction costs of $377 were allocated in proportion to the allocation of total consideration to the two units of account. The effective interest rate under the 2018 RPI Funding Agreement, including transaction costs, is approximately 27% as of June 30, 2021. 2020 RPI Funding Agreement In August 2020, the Company entered into a funding agreement with RPI 2019 Intermediate Finance Trust (“RPI 2019 IFT”) providing for up to $250,000 of funding in exchange for rights to participation payments based on global net sales of products containing zavegepant and rimegepant and certain payments based on success-based milestones relating to zavegepant (the "2020 RPI Funding Agreement"). Under the 2020 RPI Funding Agreement, RPI 2019 IFT will be entitled to receive tiered, sales based participation rights up to 3.0% of future global net sales of products containing zavegepant, 0.4% of future global net sales of products containing rimegepant, and payments tied to success-based milestones as described below. Pursuant to the 2020 RPI Funding Agreement, the Company received $150,000 on the transaction date in August 2020 and $100,000 in March 2021 upon the commencement of the oral zavegepant Phase 3 clinical program. If at any time during the 180 days following the closing of the 2020 RPI Funding Agreement, the Company enters into a definitive agreement to consummate a Change of Control (as defined in the Company's articles and memorandum of association), the Company will have the option to repurchase the participation rights and milestone payment rights for a purchase price of 2.0x of the amount received under the agreement at that date, contingent upon the closing of a Change of Control (the "Buy-Back Option"). The success-based milestone payments range from 0.6x to 2.95x of the funded amount depending on the number of regulatory approvals achieved for zavegepant (including 1.9x for the first zavegepant migraine regulatory approval) and would be paid over a 10-year period. If the Company consummates a Change of Control, and the Buy-Back Option has not previously been exercised, RPI 2019 IFT has the option to accelerate each unpaid milestone payment which has or thereafter occurs. The Company concluded that there were two units of account for the $150,000 in initial consideration received, which comprised of a liability related to sale of future royalties for products containing rimegepant and a research and development arrangement with RPI 2019 IFT for zavegepant. The Company allocated the $150,000 from the 2020 RPI Funding Agreement among the two units of account based on the present value of probability adjusted net sales at the time of the transaction. The Company allocated $147,876 in transaction consideration to the liability related to sale of future royalties and $2,124 to the obligation to perform contractual services in the condensed consolidated balance sheets. The transaction costs of $400 were allocated only to the liability related to sale of future royalties. The effective interest rate under the 2020 RPI Funding Agreement, including transaction costs, is approximately 6% as of June 30, 2021. In March 2021, the Company received $100,000 from RPI 2019 IFT for the commencement of the oral zavegepant Phase 3 clinical program. The Company allocated the proceeds to obligation to perform R&D services liability in the condensed consolidated balance sheets. Since there is a substantive and genuine transfer of risk to RPI 2019 IFT for the development of zavegepant, the $102,124 of consideration allocated to the development of zavegepant is being recognized by the Company as an obligation to perform contractual services and therefore is a reduction of research and development expenses as incurred. The reduction to research and development expenses related to the 2020 RPI Funding Agreement for the three and six months ended June 30, 2021 was $10,016 and $10,205. The following table shows the activity within the liability related to sales of future royalties account for the six months ended June 30, 2021 and 2020, respectively, related to the 2018 and 2020 RPI Funding Agreements. Six Months Ended June 30, 2021 2020 Liability related to sale of future royalties - beginning balance $ 335,282 $ 144,111 Royalty revenues payable to RPI (3,419) (228) Interest expense on liability related to sale of future royalties 28,007 19,995 Liability related to sale of future royalties - ending balance $ 359,870 $ 163,878

Mandatorily Redeemable Preferre

Mandatorily Redeemable Preferred Shares, net	6 Months Ended
	Jun. 30, 2021
Other Liabilities Disclosure [Abstract]
Mandatorily Redeemable Preferred Shares, net	Mandatorily Redeemable Preferred Shares, net In April 2019, the Company sold 2,495 Series A preferred shares (the "Series A Preferred Shares") to RPI at a price of $50,100 per preferred share pursuant to a Series A preferred share purchase agreement (the "Preferred Share Agreement"). The gross proceeds from the transaction with RPI were $125,000, with $105,000 of the proceeds used to purchase a priority review voucher ("PRV") issued by the United States Secretary of Health and Human Services to potentially expedite the regulatory review of the new drug application ("NDA") for the ODT formulation of rimegepant and the remainder of the proceeds to be used for other general corporate purposes. Pursuant to the Preferred Share Agreement, the Company had the option to issue additional Series A Preferred Shares to RPI in up to three additional closings for an aggregate amount of $75,000. The Company was not obligated to issue any additional Series A Preferred Shares, subject to a fee up to $3,000 if not all of the Series A Preferred Shares were issued. In the third quarter of 2020, the Company determined it will not exercise the option to issue additional Series A Preferred Shares and accordingly recognized the full $3,000 fee in other expense in the condensed consolidated statements of operations and comprehensive loss. The holders of the Company's outstanding Series A Preferred Shares will have the right to require redemption of the shares in certain circumstances. If a Change of Control, as defined in the Company's memorandum and article of association, occurs and the Series A Preferred Shares have not previously been redeemed, the Company must redeem the Series A Preferred Shares for two times (2x) the original purchase price of the Series A Preferred Shares payable in a lump sum at the closing of the Change of Control or in equal quarterly installments following the closing of the Change of Control through December 31, 2024. The Company may redeem the Series A Preferred Shares at its option at any time for two times (2x) the original purchase price, which redemption price may be paid in a lump sum or in equal quarterly installments through December 31, 2024. In the event that the Company defaults on any obligation to redeem Series A Preferred Shares when required, the redemption amount shall accrue interest at the rate of eighteen percent (18%) per annum. If any such default continues for at least one year, the holders of such shares shall be entitled to convert, subject to certain limitations, such Series A Preferred Shares into common shares, with no waiver of their redemption rights. The Company is required to redeem the Series A Preferred Shares for two times (2x) the original purchase price, payable beginning March 31, 2021 in equal quarterly installments through December 31, 2024. Accordingly, the Company has concluded the Series A Preferred Shares are mandatorily redeemable instruments and classified as a liability. The Company initially measured the liability at fair value, and will subsequently accrete the carrying value to the redemption value through interest expense using the effective interest rate method. The effective interest rate under the Preferred Share Agreement, including transaction costs, was determined to be approximately 20% as of June 30, 2021. The Company recognized $7,677 and $6,993 in interest expense for the three months ended June 30, 2021 and June 30, 2020, respectively. The Company recognized $15,620 and $12,554 in interest expense for the six months ended June 30, 2021 and June 30, 2020, respectively. The Company had 2,183 and 2,495 Series A Preferred Shares issued and outstanding as of June 30, 2021 and December 31, 2020, respectively. The following table shows the activity within the Series A preferred share liability for the six months ended June 30, 2021 and 2020, respectively: Carrying Value Gross balance at December 31, 2020 $ 174,264 Interest expense recognized, excluding transaction cost amortization 15,599 Redemption of Series A preferred shares (31,250) Gross balance at June 30, 2021 $ 158,613 Less: unamortized transaction costs (152) Net balance at June 30, 2021 $ 158,461 Gross balance at December 31, 2019 $ 103,864 Partial settlement of derivative liability 42,821 Interest expense recognized, excluding transaction cost amortization 12,532 Gross balance at June 30, 2020 $ 159,217 Less: unamortized transaction costs (196) Net balance at June 30, 2020 $ 159,021 Certain scenarios as described in the Preferred Share Agreement were determined by the Company to result in a derivative liability. The with-and-without valuation method was used to determine the fair value of the embedded derivatives within the agreement. As inputs into the valuation, the Company considered the type and probability of occurrence of certain events, the amount of the payments, the expected timing of certain events, and a risk-adjusted discount rate. In accordance with ASC 815, Derivatives and Hedging, the fair value of the derivative was recorded on the balance sheet as a Series A preferred shares derivative liability with changes in fair value recorded in other income (expense) in the condensed consolidated statements of operations and comprehensive loss (see Note 4 for details on the fair value measurement). Upon the FDA's approval of NURTEC ODT the Company remeasured the derivative using the inputs noted above. In the first quarter of 2020, the Company partially settled the Series A preferred shares derivative liability associated with this approval of $42,821, which modified the timing of the payment obligation related to the redeemable preferred share liability. On August 7, 2020, the Company entered into the RPI Series B Preferred Share Agreement, pursuant to which RPI agreed to invest in the Company through the purchase of up to 3,992 Series B Preferred Shares at a price of $50,100 per share. The shares will be issued in quarterly increments from March 31, 2021 to December 31, 2024. Upon issuance of the Series B Preferred Shares, they will qualify as mandatorily redeemable instruments and be classified as a mandatorily redeemable preferred shares liability on the condensed consolidated balance sheets. The Company will then measure the liability at fair value, and subsequently accrete the carrying value to the redemption value through interest expense using the effective interest rate method. The effective interest rate under the Series B Preferred Share Agreement was determined to be approximately 8%, and the Company recognized $365 in interest expense for the three and six months ended June 30, 2021. The Company had 702 and no Series B preferred shares issued and outstanding, as of June 30, 2021 and December 31, 2020, respectively. The following table shows the activity within the Series B preferred share liability for the six months ended June 30, 2021: Carrying Value Balance at December 31, 2020 $ — Interest expense recognized 365 Issuance of Series B preferred shares 36,765 Balance at June 30, 2021 $ 37,130

Shareholders' Equity (Deficit)

Shareholders' Equity (Deficit)	6 Months Ended
	Jun. 30, 2021
Stockholders' Equity Note [Abstract]
Shareholders' Equity (Deficit)	Shareholders' Equity (Deficit) Changes in shareholders’ deficit for the three and six months ended June 30, 2021 were as follows: Common Shares Shares Amount Additional Paid-in Capital Accumulated Deficit Accumulated Other Comprehensive Income Biohaven Shareholders' Equity (Deficit) Non-controlling Interests Total Shareholders' Equity (Deficit) Balances as of December 31, 2020 60,436,876 $ 1,249,547 $ 98,938 $ (1,739,169) $ 314 $ (390,370) $ (1,819) $ (392,189) Issuance of common shares as part of acquisition 115,836 10,673 — — — 10,673 — 10,673 Issuance of common shares as payment for license agreements 110,998 10,243 — — — 10,243 — 10,243 Issuance of common shares, net of offering costs 4,037,204 308,243 — — — 308,243 — 308,243 Issuance of common shares under equity incentive plan 365,554 25,315 (23,933) — — 1,382 — 1,382 Non-cash share-based compensation expense — — 48,726 — — 48,726 — 48,726 Net loss — — — (264,968) — (264,968) (360) (265,328) Other comprehensive income — — — — 95 95 — 95 Balances as of March 31, 2021 65,066,468 $ 1,604,021 $ 123,731 $ (2,004,137) $ 409 $ (275,976) $ (2,179) $ (278,155) Issuance of common shares under equity incentive plan and employee share purchase plan 173,990 14,173 (6,912) — — 7,261 — 7,261 Non-cash share-based compensation expense — — 25,586 — — 25,586 — 25,586 Net loss — — — (210,619) — (210,619) (540) (211,159) Other comprehensive loss — — — — (129) (129) — (129) Balances as of June 30, 2021 65,240,458 $ 1,618,194 $ 142,405 $ (2,214,756) $ 280 $ (453,877) $ (2,719) $ (456,596) Changes in shareholders’ equity (deficit) for the three and six months ended June 30, 2020 were as follows: Common Shares Shares Amount Additional Paid-in Capital Accumulated Deficit Accumulated Other Comprehensive Income Biohaven Shareholders' Equity (Deficit) Non-controlling Interests Total Shareholders' Equity (Deficit) Balance as of December 31, 2019 52,385,283 $ 881,426 $ 83,523 $ (972,373) $ — $ (7,424) $ — $ (7,424) Issuance of common shares, net of offering costs 5,555,554 282,833 — — — 282,833 — 282,833 Issuance of common shares under equity incentive plan 447,111 10,880 (8,273) — — 2,607 — 2,607 Non-cash share-based compensation expense — — 16,879 — — 16,879 — 16,879 Net loss — — — (172,937) — (172,937) — (172,937) Balance as of March 31, 2020 58,387,948 $ 1,175,139 $ 92,129 $ (1,145,310) $ — $ 121,958 $ — $ 121,958 Issuance of common shares under equity incentive plan 1,137,617 23,866 (12,118) — — 11,748 — 11,748 Non-cash share-based compensation expense — — 11,762 — — 11,762 — 11,762 Net loss — — — (180,934) — (180,934) — (180,934) Balance as of June 30, 2020 59,525,565 $ 1,199,005 $ 91,773 $ (1,326,244) $ — $ (35,466) $ — $ (35,466) Issuance of Common Shares for the March 2021 Offering In March 2021, the Company issued and sold 2,686,409 common shares at a public offering price of $76.00 per share for net proceeds of approximately $199,500 after deducting underwriting discounts and commissions of approximately $4,167 and other offering expenses of approximately $500. In addition, in March 2021, the underwriter of the March follow-on offering exercised its option to purchase additional shares, and the Company issued and sold 402,961 common shares for net proceeds of approximately $30,000 after deducting underwriting discounts and commissions of approximately $625. Thus, the aggregate net proceeds to the Company from the follow-on offering, after deducting underwriting discounts and commissions and other offering costs, were approximately $229,500. Acquisition of Kleo Pharmaceuticals, Inc. On January 4, 2021, the Company acquired Kleo Pharmaceuticals, Inc. (Note 6). In the merger, each share of Kleo common stock issued and outstanding immediately prior to the effective time of the merger was converted into the right to receive approximately 0.007 of a common share of the Company, rounded up to the nearest whole share. Prior to the consummation of the merger, the Company owned approximately 41.9% of the outstanding shares of Kleo through its subsidiary Therapeutics, resulting in 115,836 common shares of the Company being issued to Kleo stockholders in the merger. Yale MoDE Agreement On January 1, 2021, the Company entered into a worldwide, exclusive license agreement for the development and commercialization of a novel Molecular Degrader of Extracellular Protein (MoDEs) platform based on ground-breaking research conducted in the laboratory of Professor David Spiegel at Yale University (Note 13). Under the agreement, the Company paid Yale University an upfront cash payment of $1,000 and 11,668 shares valued at $1,000, both of which were included in research and development expense in the condensed consolidated statements of operations and comprehensive loss. Consulting Agreement with Moda Pharmaceuticals LLC On January 1, 2021, the Company entered into a consulting services agreement with Moda Pharmaceuticals LLC to further the scientific and commercial advancement of technology, drug discovery platforms, product candidates and related intellectual property owned or controlled by the Company (Note 13). Under the agreement, the Company paid Moda an upfront cash payment of $2,700 and 37,836 shares valued at $3,243, both of which were included in research and development expense in the condensed consolidated statements of operations and comprehensive loss. Equity Distribution Agreement In December 2020, the Company entered into an equity distribution agreement with Goldman Sachs & Co. LLC, Piper Sandler & Co., SVB Leerink LLC, Canaccord Genuity LLC, Mizuho Securities USA LLC, Wedbush Securities Inc., and William Blair & Company, L.L.C., as our sales agents (the "Equity Distribution Agreement"). In accordance with the terms of the Equity Distribution Agreement, we may offer and sell common shares having an aggregate offering price of up to $400,000 from time to time through or to the sales agents, acting as our agents or principals. Sales of our common shares will be made in sales deemed to be “at the market offerings” as defined in Rule 415 promulgated under the Securities Act of 1933, as amended, or the Securities Act, in ordinary brokers’ transactions, to or through a market maker, on or through the New York Stock Exchange or any other market venue where the securities may be traded, in the over-the-counter market, in privately negotiated transactions, or through a combination of any such methods of sale. The sales agents may also sell our common shares by any other method permitted by law. The sales agents are not required to sell any specific amount of securities but will act as our sales agents using commercially reasonable efforts consistent with their normal trading and sales practices, on mutually agreed terms between the sales agents and us. The Company issued and sold no shares in the three months ended June 30, 2021, and 939,328 common shares for net proceeds of approximately $78,743 during the six months ended June 30, 2021. Issuance of Series A Preferred Shares and Employee Share Options by Consolidated Subsidiary In September 2020, the Company's Asia-Pacific Subsidiary, BioShin Limited, authorized, issued and sold 15,384,613 BioShin Series A Preferred Shares at a price of $3.90 per share for a total of $60,000 to a group of investors led by OrbiMed, with participation from Cormorant Asset Management LLC, HBM Healthcare Investments Ltd, Surveyor Capital (a Citadel Company), and Suvretta Capital Management, LLC (the "BioShin Investors"). The BioShin Series A Preferred Shares contain both a call option by the Company and a put option held by the BioShin Investors. The call and put options have mirroring features that allow for the Company to buy, or the BioShin Investors to sell the preferred shares following a change of control of the Company at the greater of the fair market value of the BioShin preferred shares on execution of the options or a multiple of 2.5x to 3.5x dependent on when the change of control occurs, prior to an initial public offering of BioShin. Due to the contingently redeemable features, the Company has classified the BioShin Series A Preferred Shares in mezzanine equity since the redemption is out of the Company's control. In the event that a change of control becomes probable, the Company will accrete the carrying value of the BioShin Series A Preferred Shares to their redemption value. In connection with the BioShin Series A Preferred Shares issuance, BioShin Limited executed the 2020 Equity Incentive Plan ("BioShin 2020 Equity Incentive Plan") and granted options under the BioShin 2020 Equity Incentive Plan to certain employees. The compensation expense is measured at the grant date based on the fair value of the award and is recognized as expense over the requisite service period of the award (generally three years) using the straight-line method. The Company is accounting for the expense being recognized over the requisite service period as non-controlling interest in shareholder's equity. The Company recognized $540 and $900 in non-controlling interest relating to the options for the three and six months ended June 30, 2021, respectively. Artizan Biosciences Inc. In December 2020, the Company entered into a Series A-2 Preferred Stock Purchase Agreement with Artizan Biosciences Inc. ("Artizan") (Note 13). Under the agreement, the Company paid Artizan 61,494 shares valued at $6,000, which were issued in January 2021. In exchange, the Company acquired 34,472,031 shares of series A-2 preferred stock of Artizan. Issuance of Common Shares for the January 2020 Offering In January 2020, the Company issued and sold 4,830,917 common shares at a public offering price of $51.75 per share for net proceeds of approximately $245,877 after deducting underwriting discounts and commissions of approximately $3,623 and other offering expenses of approximately $500. In addition, in February 2020, the underwriter of the January follow-on offering exercised its option to purchase additional shares, and the Company issued and sold 724,637 common shares for net proceeds of approximately $36,956 after deducting underwriting discounts and commissions of approximately $543. Thus, the aggregate net proceeds to the Company from the follow-on offering, after deducting underwriting discounts and commissions and other offering costs, were approximately $282,833.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	6 Months Ended
	Jun. 30, 2021
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Shareholders’ deficit included the following activity in accumulated other comprehensive income for the three and six months ended June 30, 2021: Three Months Ended June 30, 2021 Six Months Ended June 30, 2021 Net unrealized investment gains (losses): Beginning of period balance $ (43) $ (125) Other comprehensive income (1) 73 136 Amounts reclassified from accumulated other comprehensive income (1) — 19 Other comprehensive income 73 155 End of period balance 30 30 Foreign currency translation adjustments: Beginning of period balance 452 439 Other comprehensive loss (1) (202) (189) End of period balance 250 250 Total beginning of period accumulated other comprehensive income 409 314 Total other comprehensive loss (129) (34) Total end of period accumulated other comprehensive income $ 280 $ 280 (1) There was no tax on other comprehensive income (loss) or amounts reclassified from accumulated other comprehensive income during the period The Company had no accumulated other comprehensive income (loss) included in shareholders' deficit as of June 30, 2020.

Share-Based Compensation

Share-Based Compensation	6 Months Ended
	Jun. 30, 2021
Share-based Payment Arrangement [Abstract]
Share-Based Compensation	Share-Based Compensation Non-Cash Share-Based Compensation Expense Non-cash share-based compensation is measured at the grant date based on the fair value of the award and is recognized as expense over the requisite service period of the award (generally three Three months ended June 30, Six months ended June 30, 2021 2020 2021 2020 Research and development expenses $ 9,273 $ 6,426 $ 29,331 $ 12,677 Selling, general and administrative expenses 16,313 5,336 44,981 15,964 Total non-cash share-based compensation expense $ 25,586 $ 11,762 $ 74,312 $ 28,641 Less: Share-based compensation expense attributable to non-controlling interests 540 — 900 — Share-based compensation expense attributable to Biohaven Pharmaceutical Holding Company Ltd. $ 25,046 $ 11,762 $ 73,412 $ 28,641 Stock Options All stock option grants are awarded at fair value on the date of grant. The fair value of stock options is estimated using the Black-Scholes option pricing model and stock-based compensation is recognized on a straight-line basis over the requisite service period. Stock options granted generally become exercisable over a three four 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 at June 30, 2021. As of June 30, 2021, the Company's unrecognized compensation expense related to unvested stock options totaled $76,622, which the Company expects to be recognized over a weighted-average period of 1.87 years. The Company expects approximately 3,167,723 of the unvested stock options to vest over the requisite service period. The following table is a summary of the Company's stock option activity for the six months ended June 30, 2021: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding as of December 31, 2020 7,545,907 $28.21 Granted 1,252,530 $82.53 Exercised (153,847) $35.05 Forfeited (70,790) $55.98 Outstanding as of June 30, 2021 8,573,800 $35.78 6.92 $ 525,563 Options exercisable as of June 30, 2021 5,406,077 $25.91 6.17 $ 384,734 Vested and expected to vest as of June 30, 2021 8,573,800 $35.78 6.92 $ 525,563 Restricted Share Units The Company’s RSUs are considered nonvested share awards and require no payment from the employee. For each RSU, employees receive one common share at the end of the vesting period. The employee can elect to receive the one common share net of taxes or pay for taxes separately and receive the entire share. Compensation cost is recorded based on the market price of the Company’s common shares on the grant date and is recognized on a straight-line basis over the requisite service period. As of June 30, 2021, there was $74,781 of total unrecognized compensation cost related to Company RSUs that are expected to vest. These costs are expected to be recognized over a weighted-average period of 2.41 years. The total fair value of RSUs vested during the six months ended June 30, 2021 was $25,846. The following table is a summary of the RSU activity for the six months ended June 30, 2021: Number of Shares Weighted Average Grant Date Fair Value Unvested outstanding as of December 31, 2020 467,160 $56.00 Granted 1,093,250 $82.86 Forfeited (25,631) $75.23 Vested (355,308) $72.74 Unvested outstanding as of June 30, 2021 1,179,471 $75.43

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Net Loss Per Share	Net Loss Per Share Basic and diluted net loss per share attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd. was calculated as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Numerator: Net loss $ (211,159) $ (180,934) $ (476,487) $ (353,871) Net loss attributable to non-controlling interests (540) — (900) — Net loss attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd. $ (210,619) $ (180,934) $ (475,587) $ (353,871) Denominator: Weighted average common shares outstanding—basic and diluted 65,112,179 58,742,329 63,584,932 57,577,384 Net loss per share attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd.—basic and diluted $ (3.23) $ (3.08) $ (7.48) $ (6.15) The Company’s potential dilutive securities, which include stock options, restricted share units, 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 the Company 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: As of June 30, 2021 2020 Options to purchase common shares 8,573,800 8,120,648 Warrants to purchase common shares 106,751 106,751 Restricted share units 1,179,471 477,798 Total 9,860,022 8,705,197

License and Other Agreements

License and Other Agreements	6 Months Ended
	Jun. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
License and Other Agreements	License and Other Agreements Yale University Agreements In September 2013, the Company entered into an exclusive license agreement with Yale University (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 addition to the obligation to issue shares to prevent anti-dilution. The obligation to contingently issue equity to Yale was no longer outstanding as of December 31, 2018. The Yale Agreement was amended and restated in May 2019. As amended, 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 riluzole-based products from the licensed patents or from products based on troriluzole. Under the amended and restated agreement, the royalty rates are reduced as compared to the original agreement. In addition, under the amended and restated agreement, the Company may develop products based on riluzole or troriluzole. The amended and restated agreement retains a minimum annual royalty of up to $1,000 per year, beginning after the first sale of product under the agreement. 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. To date, no milestone or royalty payments have been made under this agreement. In January 2021, the Company entered a worldwide, exclusive license agreement with Yale University for the development and commercialization of a novel Molecular Degrader of Extracellular Protein ("MoDE") platform (the "Yale MoDE Agreement"). Under the license agreement, Biohaven acquired exclusive, worldwide rights to Yale's intellectual property directed to its MoDE platform. The platform pertains to the clearance of disease-causing protein and other biomolecules by targeting them for lysosomal degradation using multi-functional molecules. As part of consideration for this license, the Company paid Yale University an upfront cash payment of $1,000 and 11,668 common shares valued at approximately $1,000. Under the agreement, the Company may develop products based on the MoDE platform. The agreement includes an obligation to pay a minimum annual royalty of up to $1,000 per year, and low single digit royalties on the net sales of licensed products. 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. In addition, Yale University will be eligible to receive additional development milestone payments of up to $800 and commercial milestone payments of up to $2,950. The agreement terminates on the later of twenty years from the effective date, twenty years from the filing date of the first investigational new drug application for a licensed product or the last to expire of a licensed patent. For the three and six months ended June 30, 2021, excluding the upfront payments noted above, the Company did not record any material expense, or make any milestone or royalty payments under the Yale Agreement or the Yale MoDE Agreement. ALS Biopharma Agreement In August 2015, the Company entered into an agreement (the "ALS Biopharma Agreement") with ALS Biopharma and 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 troriluzole, 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. To date, no milestone or royalty payments have been made under this agreement. 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. For the three and six months ended June 30, 2021 and 2020, the Company did not record any expense or make any milestone or royalty payments under the ALS Biopharma Agreement. Catalent Agreements for Rimegepant In January 2018, the Company entered into an exclusive world-wide license and development agreement with Catalent U.K. Swindon Zydis Limited, a subsidiary of Catalent, Inc. ("Catalent") pursuant to which the Company obtained certain license rights to the Zydis ODT technology for use with NURTEC ODT. Since NURTEC ODT utilizes the Zydis ODT technology, the agreement permits the Company to purchase the commercial product from Catalent at a fixed price, inclusive of a royalty. Under the agreement, Catalent will not develop or manufacture a formulation of any oral CGRP compound using Zydis ODT technology for itself or a third party until 2031, subject to certain minimum commercial revenues. Under this agreement, the Company is responsible for conducting clinical trials and preparing and filing regulatory submissions. The Company has the right to sublicense its rights under the agreement subject to Catalent’s prior written consent. Catalent has the right to enforce the patents covering the Zydis technology and to defend any allegation that a formulation using Zydis technology, such as NURTEC ODT, infringes a third party’s patent. This agreement terminates on a country-by-country basis upon the later of (i) 10 years after the launch of the most recently launched product in such country and (ii) the expiration of the last valid claim covering each product in such country, unless earlier voluntarily terminated by the Company or by Catalent. This agreement automatically extends for one-year terms unless either party gives advance notice of intent to terminate. In addition, Catalent may terminate the agreement either in its entirety or terminate the exclusive nature of the agreement on a country-by-country basis if, among other things, the Company fails to meet specified development timelines, which the Company may extend in certain circumstances. In connection with the agreement with Catalent, upon FDA approval of NURTEC ODT on February 27, 2020, the Company became obligated to pay Catalent up to $1,500 upon the achievement of specified regulatory and commercial milestones. The Company recorded the $1,500 in milestone payments as an intangible asset in its condensed consolidated balance sheets in the first quarter of 2020, and is amortizing the expense to cost of goods sold on its condensed consolidated statement of operations and comprehensive loss over the patent life. The Company paid $750 of the $1,500 in milestone payments to Catalent in the first quarter of 2020 and paid the remaining $750 in milestone payments in the second quarter of 2020. 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 until the first commercial sale of a licensed product, at which point the Company will pay Rutgers minimum annual royalties. 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 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 0.30% 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. The fair value of the obligation for all periods presented 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 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. For the three and six months ended June 30, 2021 and 2020, the Company did not record any material expense or make any milestone or royalty payments under the Rutgers Agreement. BMS Agreement In July 2016, the Company entered into an exclusive, worldwide license agreement with BMS (the "BMS Agreement") for the development and commercialization rights to rimegepant and zavegepant, 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 and can also be terminated if certain events occur, e.g., material breach or insolvency. In March 2018, the Company entered into an amendment to the BMS Agreement (the “2018 BMS Amendment”) Under the 2018 BMS Amendment, the Company paid BMS an upfront payment of $50,000 in return for a low single-digit reduction in the royalties payable on net sales of rimegepant and a mid single-digit reduction in the royalties payable on net sales of zavegepant, recorded in Research and Development expense in the Condensed Consolidated Statements of Operations and Comprehensive Loss. The BMS Amendment also removes BMS’s right of first negotiation to regain its intellectual property rights or enter into a license agreement with the Company following the Company’s receipt of topline data from its Phase 3 clinical trials with rimegepant, and clarifies that antibodies targeting CGRP are not prohibited as competitive compounds under the non-competition clause of the Original License Agreement. In August 2020, the Company entered into a further amendment of the BMS Agreement (the “August 2020 BMS Amendment”) Under the August 2020 BMS Amendment, the Company paid BMS an upfront payment of $5,000 in return for a reduction in the royalties payable on net sales of rimegepant and zavegepant in China, with percentages in the low to mid-single digits. In addition, the Company is obligated to pay up to $22,500 for each licensed product upon the achievement of commercial milestones in China. The August 2020 BMS Amendment also amended the BMS Agreement to remove sales in China from the commercial milestone payment obligations. In November 2020, the Company entered into a further amendment of the BMS Agreement (the “November 2020 BMS Amendment”). Under the November 2020 BMS Amendment, certain exclusivity provisions under the BMS Agreement are waived which permits the Company to develop certain CGRP compounds licensed by the Company from Heptares Therapeutics Limited (“Heptares”). Under the November 2020 Amendment, if the Company initiates clinical development of a Heptares compound prior to July 8, 2023, the Company is obligated to pay BMS certain fees based on net sales of the Heptares compounds from low single percentage to 10% and pay up to $17,500 for each Heptares compound upon the achievement of certain development milestones and up to $150,000 for each Heptares compound upon the achievement of certain commercial milestones. No fees or milestones are due by the Company to BMS for Heptares compounds that begin clinical trials after July 8, 2023. The BMS License Agreement continues to provide the Company with exclusive global development and commercialization rights to rimegepant, zavegepant and related CGRP molecules, as well as related know-how and intellectual property. The Company’s obligations to make development milestone payments to BMS under the Original License Agreement remain unchanged. In connection with the BMS Agreement, upon FDA approval of NURTEC ODT on February 27, 2020, the Company became obligated to pay BMS $40,000 in milestone payments. The Company recorded the $40,000 in milestone payments as an intangible asset on its condensed consolidated balance sheets in the first quarter of 2020, and will amortize the expense to cost of goods sold on its condensed consolidated statement of operations and comprehensive loss over the patent life. The Company paid $20,000 of the $40,000 in milestone payments to BMS in the first quarter of 2020 and the remaining $20,000 in milestone payments in the third quarter of 2020. In connection with the BMS Agreement, the Company was required to pay $2,000 to BMS on commencement of a Phase 1 clinical trial, $4,000 on commencement of a Phase 2 clinical trial, and $6,000 on commencement of a Phase 3 clinical trial, the occurrence of which the Company believes is probable, for certain milestones relating to the development of zavegepant. Accordingly, the Company recognized these liabilities in accrued expenses within the condensed consolidated balance sheets in the fourth quarter of 2018, first quarter of 2019, and fourth quarter of 2019, respectively. Per the BMS Agreement, the $2,000 and $4,000 payment obligations under the agreement were deferred until the earlier of FDA approval of rimegepant or the discontinuation of the rimegepant development program. Upon FDA approval of NURTEC ODT on February 27, 2020, the Company became obligated to pay BMS the $2,000 and $4,000 milestone payments for the commencement of the Phase 1 and Phase 2 clinical trials of zavegepant, respectively, and made the milestone payments in the second quarter of 2020. The Company paid the $6,000 milestone payment following the commencement of the Phase 3 clinical trial of zavegepant in the fourth quarter of 2020. In the first quarter of 2021, the Company accrued a $5,000 development milestone expense following the regulatory filing for rimegepant in Europe, which was paid in the second quarter of 2021. For the three and six months ended June 30, 2021, the Company recorded $9,293 and $13,678, respectively, in royalty expense in cost of goods sold on the condensed consolidated statements of operations and comprehensive loss under the BMS agreement. For the three and six months ended June 30, 2020, the Company recorded $860 and $975, respectively, in royalty expense in cost of goods sold on the condensed consolidated statements of operations and comprehensive loss under the BMS agreement. 2016 AstraZeneca Agreement In October 2016, the Company entered into an exclusive license agreement (the "2016 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 2016 AstraZeneca Agreement, the Company is also obligated to pay a portion of that revenue to AstraZeneca. To date, no payments have been made related to these milestones or royalties. 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 2016 AstraZeneca Agreement. The 2016 AstraZeneca Agreement expires upon the expiration of the patent rights under the agreement or on a country-by-country basis ten years after the first commercial sale and can also be terminated if certain events occur, e.g., material breach or insolvency. For the three and six months ended June 30, 2021 and 2020, the Company did not record any expense or make any milestone or royalty payments under the 2016 AstraZeneca Agreement. Revenue Participation Rights In June 2018, pursuant to the 2018 RPI Funding Agreement entered into by the Company and RPI (Note 7), the Company granted to RPI the right to receive certain revenue participation payments, subject to certain reductions, based on the future global net sales of the Products, for each calendar quarter during the royalty term contemplated by the 2018 RPI Funding Agreement, in exchange for $100,000 in cash. Specifically, the participation rate commences at 2.1 percent on annual global net sales of up to and equal to $1,500,000, declining to 1.5 percent on annual global net sales exceeding $1,500,000. In connection with the 2018 RPI Funding Agreement, the Company recorded, $12,049 and $23,468 in interest expense on its liability related to sale of future royalties for the three and six months ended June 30, 2021, respectively, and $11,570 and $19,995 in interest expense on its liability related to sale of future royalties for the three and six months ended June 30, 2020, respectively, The Company paid $920 and $1,656 under the 2018 RPI Funding Agreement during the three and six months ended June 30, 2021, respectively and no payments under the 2018 RPI Funding Agreement during the three and six months ended June 30, 2020. In August 2020, pursuant to the 2020 RPI Funding Agreement, the Company sold sales-based participation rights on global net sales of products containing zavegepant and rimegepant to RPI 2019 IFT for aggregate funding of $250,000, payable in two tranches. For further details on the transaction see Note 7 “Liability Related to Sale of Future Royalties, net.” In connection with the 2020 RPI Funding Agreement, the Company recorded $2,450 and $4,539 in interest expense on its liability related to sale of future royalties for the three and six months ended June 30, 2021, and no interest expense for the three and six months ended June 30, 2020 . The Company recorded payments of $175 and $315 during the three and six months ended June 30, 2021, and no payments under the 2020 RPI Funding Agreement during the three and six months ended June 30, 2020. 2018 License Agreement with AstraZeneca In September 2018, the Company entered into an exclusive license agreement (the "2018 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-3241. Under the 2018 AstraZeneca Agreement, the Company paid AstraZeneca an upfront cash payment of $3,000 and 109,523 shares valued at $4,080 on the date of settlement, both of which were included in research and development expense, and is obligated to pay milestone payments to AstraZeneca totaling up to $55,000 upon the achievement of specified regulatory and commercial milestones and up to $50,000 upon the achievement of specified sales-based milestones. In addition, we will pay AstraZeneca tiered royalties ranging from high single-digit to low double-digits based on net sales of specified approved products, subject to specified reductions. The Company plans to conduct a Phase 3 clinical trial of this product candidate, which is now referred to as verdiperstat, for the treatment of multiple system atrophy (“MSA”), a rare, rapidly progressive and fatal neurodegenerative disease with no cure or effective treatments. The Company is solely responsible, and has agreed to use commercially reasonable efforts, for all development, regulatory and commercial activities related to verdiperstat. The Company may sublicense its rights under the agreement and, if it does so, will be obligated to pay a portion of any milestone payments received from the sublicense to AstraZeneca in addition to any milestone payments it would otherwise be obligated to pay. The Agreement terminates on a country-by-country basis and product-by-product basis upon the expiration of the royalty term for such product in such country and can also be terminated if certain events occur, e.g., material breach or insolvency. For the three and six months ended June 30, 2021 and 2020, excluding the upfront payments noted above, the Company did not record any material expense or make any milestone or royalty payments under the 2018 AstraZeneca Agreement. Fox Chase Chemical Diversity Center Inc. Agreement In May 2019, Biohaven entered into the FCCDC Agreement in which the Company purchased certain intellectual property relating to the TDP-43 protein from FCCDC. The FCCDC Agreement provides the Company with a plan and goal to identify one or more new chemical entity candidates for preclinical development for eventual clinical evaluation for the treatment of one or more TDP-43 proteinopathies. As consideration, Biohaven issued 100,000 of its common shares to FCCDC valued at $5,646. The payment was recorded in research and development expense in the consolidated statement of operations for the year ended December 31, 2019. In addition, Biohaven is obligated to pay FCCDC milestone payments totaling up to $4,500 with $1,000 for each additional NDA filing. The Company also issued a warrant to FCCDC, granting FCCDC the option to purchase up to 100,000 Biohaven common shares, at a strike price of $56.46 per share, subject to vesting upon achievement of certain milestones in development of TD-43. In connection with the FCCDC Agreement, Biohaven and FCCDC have established a TDP-43 Research Plan which was amended in November 2020, that provides for certain milestones to be achieved by FCCDC, and milestone payments to be made by the Company up to approximately $3,800 over a period of up to 30 months as success fees for research activities by FCCDC. In addition to the milestone payments, the Company will pay FCCDC an earned royalty equal to 0% to 10% of net sales of any TD-43 patent products with a valid claim as defined in the FCCDC Agreement. The Company may also license the rights developed under the FCCDC Agreement and, if it does so, will be obligated to pay a portion of any payments received from such licensee to FCCDC in addition to any milestones payments it would otherwise be obligated to pay. The Company is also responsible for the prosecution and maintenance of the patents related to the TDP-43 assets. The FCCDC Agreement terminates on a country-by-country basis and product-by-product basis upon expiration of the royalty term for such product in such country and can also be terminated if certain events occur, e.g., material breach or insolvency. The Company recorded $509 and $1,321 in research and development expense in the condensed consolidated statements of operations and comprehensive loss related to the Research Plan milestones with FCCDC during the three and six months ended June 30, 2021, respectively. The Company recorded $450 and $1,405 of expense related to this agreement during the three and six months ended June 30, 2020, respectively. Sosei Heptares In November 2020, the Company entered into a global collaboration and license agreement with Heptares Therapeutics Ltd. (the "Heptares Agreement") to obtain rights to develop, manufacture and commercialize a portfolio of novel, small-molecule CGRP receptor antagonists discovered by Sosei Heptares for the treatment of CGRP-mediated disorders. The portfolio includes the lead candidate BHV-3100 (also known as "HTL0022562"), which has advanced through preclinical development demonstrating promising and differentiated properties for further investigation in human trials. As part of consideration for this license, the Company paid Sosei Heptares an upfront cash payment of $5,000 and 54,617 shares valued at $4,858, both of which were included in research and development expense on the consolidated statement of operations. In addition, Sosei Heptares will be eligible to receive additional development, regulatory and commercialization milestone payments of up to $370,000, as well as earned royalties equal to zero to ten percent of net sales of products resulting from the collaboration. The royalty payments are payable on a country-by-country and licensed product-by-licensed product basis from the date of commercial launch of a licensed product by Biohaven until the later of: (a) the expiration of the last valid claim covering the composition of matter of such licensed product, or its use or manufacture, in such country; (b) expiration of the regulatory exclusivity period for such licensed product in the relevant country; and (c) ten (10) years following the date of the commercial launch of such licensed product in the relevant country. Biohaven has the right to terminate the Heptares Agreement for any reason or no reason: (a) in its entirety during the research term on one hundred and eighty (180) days’ written notice to Sosei Heptares; and (b) following the end of the research term, in its entirety or on a country-by-country basis, on ninety (90) days’ prior written notice to Sosei Heptares. Biohaven will remain liable to pay (a) any milestone payments that have become due for payment and/or (b) royalty payments on net sales by Biohaven, in each case (a) and (b) on or before the termination date. Heptares has the right to terminate the Heptares Agreement on thirty (30) days’ written notice to Biohaven if after the end of the research term, for a continuous period of not less than three hundred and sixty five (365) days, no material Development activities have been undertaken by or on behalf of Biohaven on any licensed product; provided that, at least three (3) months prior to exercising such termination right Heptares must notify Biohaven of its concerns and the parties shall discuss in good faith the reasons why Biohaven is not undertaking such material development activities and its plans for recommencing such activities. For the three and six months ended June 30, 2021, in addition to the upfront payments noted above, the Company recorded $2,868 and $3,485, respectively, in research and development expense related to the Heptares Agreement. Artizan Biosciences Inc. In December 2020, Biohaven entered into an Option and License Agreement with Artizan Biosciences Inc. (the "Artizan Agreement"). Pursuant to the Artizan Agreement, Biohaven acquired an option (“Biohaven Option”) to obtain a royalty-based license from Artizan to manufacture, use and commercialize certain products in the United States. The Biohaven Option is exercisable throughout the development phase of the products at an exercise price of approximately $4,000 to $8,000, which varies based on the market potential of the products. Biohaven and Artizan have also formed a JSC to oversee, review and coordinate the product development activities with regard to all products for which Biohaven has (or has exercised in the future) the Biohaven Option. In December 2020, simultaneously with the Option and License Agreement, the Company and Artizan entered into a Series A-2 Preferred Stock Purchase Agreement, under which Biohaven acquired 34,472,031 shares of series A-2 preferred stock (the “Series A-2 Preferred Stock”) of Artizan, for a total purchase price of approximately $6,000. The purchase price was paid in shares of Biohaven’s common stock in January 2021. The Company recorded the fair value of the Series A-2 Preferred Stock as an other asset on its consolidated balance sheets. For the three and six months ended June 30, 2021, excluding the upfront payments noted above, the Company did not record any research and development expense or make any milestone payments related to the Artizan Agreement. Moda Pharmaceuticals LLC. On January 1, 2021, the Company entered into a consulting services agreement with Moda Pharmaceuticals LLC (the "Moda Agreement") to further the scientific advancement of technology, drug discovery platforms (including the technology licensed under the Yale MoDE Agreement), product candidates and related intellectual property owned or controlled by the Company. Under the Moda Agreement, the Company paid Moda an upfront cash payment of $2,700 and 37,836 shares valued at approximately $3,243. In addition

Debt

Debt	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Debt	DebtIn August 2020, the Borrowers, entered into the Sixth Street Financing Agreement, as amended, pursuant to which the Lenders agreed to extend a senior secured credit facility to the Company providing for term loans in an aggregate principal amount up to $500,000 plus any capitalized interest paid in kind. The facility consists of an initial term loan of $275,000, which the Borrowers borrowed at closing, and delayed draw term loans in an aggregate principal amount not exceeding $225,000, available until August 31, 2021. The facility terminates and the term loans become due and payable in August 2025. For additional information on the credit facility and outstanding term loan, see Note 19 “Debt” in the 2020 Form 10-K. The following table is a summary of the Company’s borrowing as of June 30, 2021: June 30, 2021 Long-term debt Floating rate note due August 2025 (10.00% at June 30, 2021) (1) $ 285,127 Total debt principal 285,127 Unamortized debt discount and issuance costs (10,989) Less: current portion — Long-term debt $ 274,138

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Summarized below are the matters previously described in Note 20 of the Notes to the Consolidated Financial Statements in the Company's Form 10-K for the year ended December 31, 2020, updated as applicable. Research Commitments The Company has entered into agreements with several contract research organizations to provide services in connection with its preclinical studies and clinical trials. The Company commits to minimum payments under these arrangements. 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 certain executive officers and 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 articles of association also provide for indemnification of directors and officers in specified 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 condensed consolidated financial statements as of June 30, 2021 or December 31, 2020. Legal Proceedings From time to time, in the ordinary course of business, the Company is subject to litigation and regulatory examinations as well as information gathering requests, inquiries and investigations. As of June 30, 2021, there were no matters which would have a material impact on the Company’s financial results.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed 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 controlled subsidiaries after elimination of all significant intercompany accounts and transactions. Investments in 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 financial statements of our subsidiaries with functional currencies other than the U.S. dollar are translated into U.S. dollars using period-end exchange rates for assets and liabilities, historical exchange rates for shareholders' equity (deficit) and weighted average exchange rates for operating results. Translation gains and losses are included in accumulated other
Reclassifications	Reclassifications Certain items in the prior period’s condensed consolidated financial statements have been reclassified to conform to the current presentation.
Use of Estimates	Use of Estimates The preparation of condensed 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 condensed consolidated financial statements and the reported amounts of income and expenses during the reporting periods. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, revenue recognition, interest expense on liability related to sale of future royalties, valuation of Series B preferred shares forward contracts and income taxes. 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.
Inventory	Inventory The Company values its inventories at the lower-of-cost or net realizable value. The Company determines the cost of its inventories, which includes costs related to products held for sale in the ordinary course of business, products in process of production for such sale and items to be currently consumed in the production of goods to be available for sale, on a first-in, first-out (FIFO) basis. Due to the nature of the Company’s supply chain process, inventory that is owned by the Company, is physically stored at third-party warehouses, logistics providers and contract manufacturers. The Company classifies inventory costs as noncurrent when we expect to utilize the inventory beyond our normal operating cycle and includes these costs in other assets in our condensed consolidated balance sheets. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period, and writes down any excess and obsolete inventories to their net realizable value in the period in which the impairment is first identified. If they occur, such impairment charges are recorded as a component of cost of goods sold in the consolidated statements of operations. The Company capitalizes inventory costs associated with products following regulatory approval when future commercialization is considered probable and the future economic benefit is expected to be realized. Products which may be used in clinical development programs are excluded from inventory and charged to research and development expense in the consolidated statement of operations as incurred. Prior to the initial date regulatory approval is received, costs related to the production of inventory are recorded as research and development expense on the Company’s consolidated statements of operations in the period incurred. Following FDA approval of NURTEC ODT on February 27, 2020, the Company subsequently began capitalizing costs related to inventory manufacturing.
Acquisitions	AcquisitionsOur condensed consolidated financial statements include the operations of acquired businesses after the completion of the acquisitions. We account for acquired businesses using the acquisition method of accounting, which requires, among other things, that most assets acquired and liabilities assumed be recognized at their estimated fair values as of the acquisition date and that the fair value of acquired In-Process Research and Development ("IPR&D") be recorded on the balance sheet. Transaction costs are expensed as incurred. Any excess of the consideration transferred over the assigned values of the net assets acquired is recorded as goodwill. Contingent consideration in a business acquisition is included as part of the consideration transferred and is recognized at fair value as of the acquisition date. Fair value is generally estimated by using a probability-weighted discounted cash flow approach.
Acquired In-Process Research and Development	Acquired In-Process Research and Development IPR&D that the Company acquires in conjunction with the acquisition of a business represents the fair value assigned to incomplete research projects which, at the time of acquisition, have not reached technological feasibility. The amounts are capitalized and are accounted for as indefinite-lived intangible assets, subject to impairment testing until completion or
Obligation to Perform Research and Development Services	Obligation to Perform Research and Development Services The Company accounts for obligations to perform Research and Development ("R&D") services by recording the consideration received as a liability, which then is recognized in the condensed consolidated statement of operations and comprehensive loss as an offset to R&D expense using the percentage completion method. The percentage complete is determined based on incurred R&D costs as a percent of the total forecasted costs of the contractual R&D commitment.
Unaudited Interim Condensed Consolidated Financial Information	Unaudited Interim Condensed Consolidated Financial Information The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America for interim financial information. The accompanying unaudited condensed consolidated financial statements do not include all of the information and footnotes required by accounting principles generally accepted in the United States of America for complete consolidated financial statements. The accompanying year-end condensed consolidated balance sheet was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America. The unaudited interim condensed 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 June 30, 2021 and the results of its operations for the three and six months ended June 30, 2021 and 2020 and its cash flows for the six months ended June 30, 2021 and 2020. The results for the three and six months ended June 30, 2021 are not necessarily indicative of results to be expected for the year ending December 31, 2021, any other interim periods or any future year or period. The financial information included herein should be read in conjunction with the financial statements and notes in the Company's Annual Report on Form 10-K for the year ended December 31, 2020.
Recently Adopted and Future Adoption of New Accounting Pronouncements	Recently Adopted Accounting Pronouncements Effective January 1, 2021, the Company adopted ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes ("ASU 2019-12"). This ASU simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740. The amendments also improve consistent application of and simplify GAAP for other areas of Topic 740 by clarifying and amending existing guidance. The adoption of ASU 2019-12 did not have a material impact on the Company's condensed consolidated financial statements. Future Adoption of New Accounting Pronouncements In August 2020 the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity . The update addresses issues identified as a result of the complexity associated with applying GAAP for certain financial instruments with characteristics of liabilities and equity. The amendments in ASU 2020-06 are effective for fiscal years beginning after December 15, 2021, with early adoption permitted, but no earlier than fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. Adoption of the standard requires changes to be made through either a modified retrospective method of transition or a fully retrospective method. In applying the modified retrospective method, the updated guidance is applied to transactions outstanding as of the beginning of the fiscal year in which the amendments are adopted. The Company is currently evaluating the impact that the adoption of ASU 2020-06 will have on its condensed consolidated financial statements. In January 2021 the FASB issued ASU No. 2021-01, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting, providing temporary guidance to ease the burden in accounting for reference rate reform primarily resulting from the discontinuation of LIBOR, which is currently expected to occur in mid-2023 for legacy contracts. The amendments in 2021-01 are elective immediately and apply to all entities that have contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued. The Company is currently evaluating the impact that the adoption of ASU 2021-01 will have on its condensed consolidated financial statements. In May 2021 the FASB issued ASU No. 2021-04, Earnings Per Share (Topic 260), Debt—Modifications and Extinguishments (Subtopic 470-50), Compensation—Stock Compensation (Topic 718), and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Issuer’s Accounting for Certain Modifications or Exchanges of Freestanding Equity-Classified Written Call Options (a consensus of the FASB Emerging Issues Task Force), which provides guidance on modifications or exchanges of a freestanding equity-classified written call option that is not within the scope of another topic. An entity should treat a modification of the terms or conditions or an exchange of a freestanding equity-classified written call option that remains equity classified after modification or exchange as an exchange of the original instrument for a new instrument, and provides further guidance on measuring the effect of a modification or an exchange of a freestanding equity-classified written call option that remains equity classified after modification or exchange. ASU 2021-04 also provides guidance on the recognition of the effect of a modification or an exchange of a freestanding equity-classified written call option that remains equity classified after modification or exchange on the basis of the substance of the transaction, in the same manner as if cash had been paid as consideration. The guidance is applied prospectively and is effective for all entities for fiscal years beginning after 15 December 2021, and interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the impact that the adoption of ASU 2021-04 will have on the condensed consolidated financial statements. The effect will largely depend on the terms of written call options or financings issued or modified in the future.

Marketable Securities (Tables)

Marketable Securities (Tables)	6 Months Ended
	Jun. 30, 2021
Investments, Debt and Equity Securities [Abstract]
Schedule of reconciliation of available-for-sale debt securities from amortized cost to fair value	The amortized cost, gross unrealized holding gains, gross unrealized holding losses and fair value of available-for-sale debt securities by type of security at June 30, 2021 was as follows: Amortized Cost Allowance for Credit Losses Net Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Corporate bonds U.S. $ 46,172 $ — $ 46,172 $ 35 $ (2) $ 46,205 Foreign 13,637 — 13,637 — (2) 13,635 Total $ 59,809 $ — $ 59,809 $ 35 $ (4) $ 59,840 The amortized cost, gross unrealized holding gains, gross unrealized holding losses and fair value of available-for-sale debt securities by type of security at December 31, 2020 was as follows: Amortized Cost Allowance for Credit Losses Net Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Corporate bonds U.S. $ 185,989 $ — $ 185,989 $ 1 $ (106) $ 185,884 Foreign 37,321 — 37,321 1 (21) 37,301 Total $ 223,310 $ — $ 223,310 $ 2 $ (127) $ 223,185
Schedule of available-for-sale debt securities by classification	The fair values of debt securities available-for-sale by classification in the condensed consolidated balance sheets were as follows: June 30, 2021 December 31, 2020 Marketable securities $ 59,840 $ 223,185
Schedule of available-for-sale debt securities by contractual maturity	The net amortized cost and fair value of debt securities available-for-sale at June 30, 2021 are shown below by contractual maturity. Actual maturities may differ from contractual maturities because securities may be restructured, called or prepaid, or the Company intends to sell a security prior to maturity. Net Amortized Cost Fair Value Due to mature: Less than one year $ 59,809 $ 59,840
Schedule of net investment income	Sources of net investment income included in other income (expense) in the condensed consolidated statements of operations and comprehensive loss for the three and six months ended June 30, 2021 were as follows: Three Months Ended June 30, 2021 Six Months Ended June 30, 2021 Gross investment income from debt securities available-for-sale $ 89 $ 161 Investment expenses (24) (76) Net investment income (excluding net realized capital gains or losses) 65 85 Net realized capital gains (losses) — 19 Net investment income $ 65 $ 104

Fair Value of Financial Asset_2

Fair Value of Financial Assets and Liabilities (Tables)	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Schedule of financial assets and liabilities measured at fair value on a recurring basis	Financial assets and liabilities measured at fair value on a recurring basis on the condensed consolidated balance sheet at June 30, 2021 and December 31, 2020 were as follows: Fair Value Measurement as of June 30, 2021 Using: Balance Sheet Classification Type of Instrument Level 1 Level 2 Level 3 Total Assets: Cash equivalents Money market funds $ 145,462 $ — $ — $ 145,462 Marketable securities U.S. corporate bonds — 46,205 — 46,205 Marketable securities Foreign corporate bonds — 13,635 — 13,635 Total assets $ 145,462 $ 59,840 $ — $ 205,302 Liabilities: Series B preferred shares forward contracts $ — $ — $ 15,890 $ 15,890 Contingent value right liability — — 1,457 1,457 Total liabilities $ — $ — $ 17,347 $ 17,347 Fair Value Measurement as of December 31, 2020 Using: Balance Sheet Classification Type of Instrument Level 1 Level 2 Level 3 Total Assets: Cash equivalents Money market funds $ 6,858 $ — $ — $ 6,858 Marketable securities U.S. corporate bonds — 185,884 — 185,884 Marketable securities Foreign corporate bonds — 37,301 — 37,301 Total assets $ 6,858 $ 223,185 $ — $ 230,043 Liabilities: Series B preferred shares forward contracts $ — $ — $ 14,190 $ 14,190 Total liabilities $ — $ — $ 14,190 $ 14,190
Schedule of aggregate fair value of liability determined by Level 3 inputs	The following table provides a roll forward of the aggregate fair value of the Company's Series B Preferred Shares Forward Contracts for which fair value is determined by Level 3 inputs for the six months ended June 30, 2021: Forward Contracts Balance at December 31, 2020 $ 14,190 Change in fair value 1,700 Balance at June 30, 2021 $ 15,890 The following table provides a roll forward of the aggregate fair value of the Company’s Series A preferred shares derivative liability for which fair value is determined by Level 3 inputs for the six months ended June 30, 2020: Series A Derivative Balance at December 31, 2019 $ 37,690 Change in fair value of derivative liability 5,131 Partial settlement of derivative liability (42,821) Balance at June 30, 2020 $ —

Balance Sheet Components (Table

Balance Sheet Components (Tables)	6 Months Ended
	Jun. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of reconciliation of total cash, cash equivalents and restricted cash	The following represents a reconciliation of cash and cash equivalents in the condensed consolidated balance sheets to total cash, cash equivalents and restricted cash as of June 30, 2021 and December 31, 2020, respectively, in the condensed consolidated statement of cash flows: June 30, 2021 December 31, 2020 Cash and cash equivalents $ 306,267 $ 132,149 Restricted cash (included in other current assets) 1,132 1,082 Restricted cash (included in other assets) 750 1,000 Cash, cash equivalents and restricted cash in the statement of cash flows $ 308,149 $ 134,231
Schedule of inventories	Inventories consisted of the following: As of June 30, 2021 As of December 31, 2020 Raw materials $ — $ 931 Work-in-process 94,324 33,266 Finished goods 3,462 5,366 Total inventories $ 97,786 $ 39,563 Less noncurrent inventories (1) 33,728 — Total inventories classified as current $ 64,058 $ 39,563 (1) Included in other assets on the condensed consolidated balance sheets. There are no recoverability issues for these amounts.
Schedule of prepaid expenses and other current assets	Prepaid expenses consisted of the following: As of June 30, 2021 As of December 31, 2020 Prepaid clinical trial costs $ 24,108 $ 21,173 Prepaid manufacturing 2,919 36,040 Prepaid commercial costs 19,326 16,448 Other prepaid expenses 2,518 3,021 Prepaid expenses $ 48,871 $ 76,682
Schedule of accrued expenses and other current liabilities	Accrued expenses and other current liabilities consisted of the following: As of June 30, 2021 As of December 31, 2020 Accrued development milestones $ 500 $ 667 Accrued employee compensation and benefits 26,964 29,447 Accrued clinical trial costs 29,972 19,887 Accrued commercialization and other professional fees 27,273 6,336 Accrued sales discounts and allowances 104,668 73,155 Current obligation to perform R&D services 37,466 846 Other accrued expenses and other current liabilities 49,787 36,292 Accrued expenses and other current liabilities $ 276,630 $ 166,630

Liability Related to Sale of _2

Liability Related to Sale of Future Royalties (Tables)	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Schedule of liability for sale of future royalties	The following table shows the activity within the liability related to sales of future royalties account for the six months ended June 30, 2021 and 2020, respectively, related to the 2018 and 2020 RPI Funding Agreements. Six Months Ended June 30, 2021 2020 Liability related to sale of future royalties - beginning balance $ 335,282 $ 144,111 Royalty revenues payable to RPI (3,419) (228) Interest expense on liability related to sale of future royalties 28,007 19,995 Liability related to sale of future royalties - ending balance $ 359,870 $ 163,878

Mandatorily Redeemable Prefer_2

Mandatorily Redeemable Preferred Shares, net (Tables)	6 Months Ended
	Jun. 30, 2021
Series A preferred shares
Mandatorily Redeemable Preferred Shares
Schedule of activity within the preferred share liability	The following table shows the activity within the Series A preferred share liability for the six months ended June 30, 2021 and 2020, respectively: Carrying Value Gross balance at December 31, 2020 $ 174,264 Interest expense recognized, excluding transaction cost amortization 15,599 Redemption of Series A preferred shares (31,250) Gross balance at June 30, 2021 $ 158,613 Less: unamortized transaction costs (152) Net balance at June 30, 2021 $ 158,461 Gross balance at December 31, 2019 $ 103,864 Partial settlement of derivative liability 42,821 Interest expense recognized, excluding transaction cost amortization 12,532 Gross balance at June 30, 2020 $ 159,217 Less: unamortized transaction costs (196) Net balance at June 30, 2020 $ 159,021
Series B preferred shares
Mandatorily Redeemable Preferred Shares
Schedule of activity within the preferred share liability	The following table shows the activity within the Series B preferred share liability for the six months ended June 30, 2021: Carrying Value Balance at December 31, 2020 $ — Interest expense recognized 365 Issuance of Series B preferred shares 36,765 Balance at June 30, 2021 $ 37,130

Shareholders' Equity (Deficit)

Shareholders' Equity (Deficit) (Tables)	6 Months Ended
	Jun. 30, 2021
Stockholders' Equity Note [Abstract]
Schedule of changes in shareholders' equity (deficit)	Changes in shareholders’ deficit for the three and six months ended June 30, 2021 were as follows: Common Shares Shares Amount Additional Paid-in Capital Accumulated Deficit Accumulated Other Comprehensive Income Biohaven Shareholders' Equity (Deficit) Non-controlling Interests Total Shareholders' Equity (Deficit) Balances as of December 31, 2020 60,436,876 $ 1,249,547 $ 98,938 $ (1,739,169) $ 314 $ (390,370) $ (1,819) $ (392,189) Issuance of common shares as part of acquisition 115,836 10,673 — — — 10,673 — 10,673 Issuance of common shares as payment for license agreements 110,998 10,243 — — — 10,243 — 10,243 Issuance of common shares, net of offering costs 4,037,204 308,243 — — — 308,243 — 308,243 Issuance of common shares under equity incentive plan 365,554 25,315 (23,933) — — 1,382 — 1,382 Non-cash share-based compensation expense — — 48,726 — — 48,726 — 48,726 Net loss — — — (264,968) — (264,968) (360) (265,328) Other comprehensive income — — — — 95 95 — 95 Balances as of March 31, 2021 65,066,468 $ 1,604,021 $ 123,731 $ (2,004,137) $ 409 $ (275,976) $ (2,179) $ (278,155) Issuance of common shares under equity incentive plan and employee share purchase plan 173,990 14,173 (6,912) — — 7,261 — 7,261 Non-cash share-based compensation expense — — 25,586 — — 25,586 — 25,586 Net loss — — — (210,619) — (210,619) (540) (211,159) Other comprehensive loss — — — — (129) (129) — (129) Balances as of June 30, 2021 65,240,458 $ 1,618,194 $ 142,405 $ (2,214,756) $ 280 $ (453,877) $ (2,719) $ (456,596) Changes in shareholders’ equity (deficit) for the three and six months ended June 30, 2020 were as follows: Common Shares Shares Amount Additional Paid-in Capital Accumulated Deficit Accumulated Other Comprehensive Income Biohaven Shareholders' Equity (Deficit) Non-controlling Interests Total Shareholders' Equity (Deficit) Balance as of December 31, 2019 52,385,283 $ 881,426 $ 83,523 $ (972,373) $ — $ (7,424) $ — $ (7,424) Issuance of common shares, net of offering costs 5,555,554 282,833 — — — 282,833 — 282,833 Issuance of common shares under equity incentive plan 447,111 10,880 (8,273) — — 2,607 — 2,607 Non-cash share-based compensation expense — — 16,879 — — 16,879 — 16,879 Net loss — — — (172,937) — (172,937) — (172,937) Balance as of March 31, 2020 58,387,948 $ 1,175,139 $ 92,129 $ (1,145,310) $ — $ 121,958 $ — $ 121,958 Issuance of common shares under equity incentive plan 1,137,617 23,866 (12,118) — — 11,748 — 11,748 Non-cash share-based compensation expense — — 11,762 — — 11,762 — 11,762 Net loss — — — (180,934) — (180,934) — (180,934) Balance as of June 30, 2020 59,525,565 $ 1,199,005 $ 91,773 $ (1,326,244) $ — $ (35,466) $ — $ (35,466)

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	6 Months Ended
	Jun. 30, 2021
Equity [Abstract]
Schedule of activity in accumulated other comprehensive income (loss)	Shareholders’ deficit included the following activity in accumulated other comprehensive income for the three and six months ended June 30, 2021: Three Months Ended June 30, 2021 Six Months Ended June 30, 2021 Net unrealized investment gains (losses): Beginning of period balance $ (43) $ (125) Other comprehensive income (1) 73 136 Amounts reclassified from accumulated other comprehensive income (1) — 19 Other comprehensive income 73 155 End of period balance 30 30 Foreign currency translation adjustments: Beginning of period balance 452 439 Other comprehensive loss (1) (202) (189) End of period balance 250 250 Total beginning of period accumulated other comprehensive income 409 314 Total other comprehensive loss (129) (34) Total end of period accumulated other comprehensive income $ 280 $ 280 (1) There was no tax on other comprehensive income (loss) or amounts reclassified from accumulated other comprehensive income during the period

Share-Based Compensation (Table

Share-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2021
Share-based Payment Arrangement [Abstract]
Schedule of non-cash share-based compensation expense	Non-cash share-based compensation expense, consisting of expense for stock options, Restricted Share Units ("RSUs") and Employee Share Purchase Plan ("ESPP"), was classified in the condensed consolidated statements of operations and comprehensive loss as follows: Three months ended June 30, Six months ended June 30, 2021 2020 2021 2020 Research and development expenses $ 9,273 $ 6,426 $ 29,331 $ 12,677 Selling, general and administrative expenses 16,313 5,336 44,981 15,964 Total non-cash share-based compensation expense $ 25,586 $ 11,762 $ 74,312 $ 28,641 Less: Share-based compensation expense attributable to non-controlling interests 540 — 900 — Share-based compensation expense attributable to Biohaven Pharmaceutical Holding Company Ltd. $ 25,046 $ 11,762 $ 73,412 $ 28,641
Schedule of stock option activity	The following table is a summary of the Company's stock option activity for the six months ended June 30, 2021: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding as of December 31, 2020 7,545,907 $28.21 Granted 1,252,530 $82.53 Exercised (153,847) $35.05 Forfeited (70,790) $55.98 Outstanding as of June 30, 2021 8,573,800 $35.78 6.92 $ 525,563 Options exercisable as of June 30, 2021 5,406,077 $25.91 6.17 $ 384,734 Vested and expected to vest as of June 30, 2021 8,573,800 $35.78 6.92 $ 525,563
Schedule of RSU activity	The following table is a summary of the RSU activity for the six months ended June 30, 2021: Number of Shares Weighted Average Grant Date Fair Value Unvested outstanding as of December 31, 2020 467,160 $56.00 Granted 1,093,250 $82.86 Forfeited (25,631) $75.23 Vested (355,308) $72.74 Unvested outstanding as of June 30, 2021 1,179,471 $75.43

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Schedule of basic and diluted net loss per share	Basic and diluted net loss per share attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd. was calculated as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Numerator: Net loss $ (211,159) $ (180,934) $ (476,487) $ (353,871) Net loss attributable to non-controlling interests (540) — (900) — Net loss attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd. $ (210,619) $ (180,934) $ (475,587) $ (353,871) Denominator: Weighted average common shares outstanding—basic and diluted 65,112,179 58,742,329 63,584,932 57,577,384 Net loss per share attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd.—basic and diluted $ (3.23) $ (3.08) $ (7.48) $ (6.15)
Schedule of potentially anti-dilutive securities excluded from calculation of diluted net loss per share	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: As of June 30, 2021 2020 Options to purchase common shares 8,573,800 8,120,648 Warrants to purchase common shares 106,751 106,751 Restricted share units 1,179,471 477,798 Total 9,860,022 8,705,197

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Summary of borrowings	The following table is a summary of the Company’s borrowing as of June 30, 2021: June 30, 2021 Long-term debt Floating rate note due August 2025 (10.00% at June 30, 2021) (1) $ 285,127 Total debt principal 285,127 Unamortized debt discount and issuance costs (10,989) Less: current portion — Long-term debt $ 274,138

Marketable Securities - Amortiz

Marketable Securities - Amortized Cost and Fair Value of Debt Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Fair Value to Amortized Cost
Amortized Cost	$ 59,809	$ 223,310
Allowance for Credit Losses	0	0
Net Amortized Cost	59,809	223,310
Gross Unrealized Gains	35	2
Gross Unrealized Losses	(4)	(127)
Fair Value	59,840	223,185
Corporate bonds - U.S.
Fair Value to Amortized Cost
Amortized Cost	46,172	185,989
Allowance for Credit Losses	0	0
Net Amortized Cost	46,172	185,989
Gross Unrealized Gains	35	1
Gross Unrealized Losses	(2)	(106)
Fair Value	46,205	185,884
Corporate bonds - Foreign
Fair Value to Amortized Cost
Amortized Cost	13,637	37,321
Allowance for Credit Losses	0	0
Net Amortized Cost	13,637	37,321
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(2)	(21)
Fair Value	$ 13,635	$ 37,301

Marketable Securities - Narrati

Marketable Securities - Narrative (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)investment	Jun. 30, 2020USD ($)	Dec. 31, 2020USD ($)investment
Investments, Debt and Equity Securities [Abstract]
Number of available-for-sale debt securities in an unrealized loss position | investment		9		47
Aggregate fair value of available-for-sale debt securities in an unrealized loss position | $		$ 31,387		$ 212,378
Investments in continuous unrealized loss position for more than twelve months | investment		0		0
Sales and maturities of marketable securities | $	$ 0	$ 162,293	$ 0

Marketable Securities - Classif

Marketable Securities - Classification Debt Securities Available-for-Sale (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Debt securities available-for-sale	$ 59,840	$ 223,185
Marketable securities
Debt Securities, Available-for-sale [Line Items]
Debt securities available-for-sale	$ 59,840	$ 223,185

Marketable Securities - Contrac

Marketable Securities - Contractual Maturities (Details) $ in Thousands	Jun. 30, 2021USD ($)
Net Amortized Cost
Less than one year	$ 59,809
Fair Value
Less than one year	$ 59,840

Marketable Securities - Net Inv

Marketable Securities - Net Investment Income (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Net investment income
Gross investment income from debt securities available-for-sale	$ 89,000		$ 161,000
Investment expenses	(24,000)		(76,000)
Net investment income (excluding net realized capital gains or losses)	65,000		85,000
Net realized capital gains (losses)	0		19,000
Net investment income	$ 65,000	$ 0	$ 104,000	$ 0

Fair Value of Financial Asset_3

Fair Value of Financial Assets and Liabilities - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Assets:
Total assets	$ 205,302	$ 230,043
Liabilities:
Contingent value right liability	1,457
Total liabilities	17,347	14,190
Series B preferred shares forward contracts
Liabilities:
Derivative contracts	15,890	14,190
Money market funds
Assets:
Cash equivalents	145,462	6,858
U.S. corporate bonds
Assets:
Marketable securities	46,205	185,884
Foreign corporate bonds
Assets:
Marketable securities	13,635	37,301
Level 1
Assets:
Total assets	145,462	6,858
Liabilities:
Contingent value right liability	0
Total liabilities	0	0
Level 1 | Series B preferred shares forward contracts
Liabilities:
Derivative contracts	0	0
Level 1 | Money market funds
Assets:
Cash equivalents	145,462	6,858
Level 1 | U.S. corporate bonds
Assets:
Marketable securities	0	0
Level 1 | Foreign corporate bonds
Assets:
Marketable securities	0	0
Level 2
Assets:
Total assets	59,840	223,185
Liabilities:
Contingent value right liability	0
Total liabilities	0	0
Level 2 | Series B preferred shares forward contracts
Liabilities:
Derivative contracts	0	0
Level 2 | Money market funds
Assets:
Cash equivalents	0	0
Level 2 | U.S. corporate bonds
Assets:
Marketable securities	46,205	185,884
Level 2 | Foreign corporate bonds
Assets:
Marketable securities	13,635	37,301
Level 3
Assets:
Total assets	0	0
Liabilities:
Contingent value right liability	1,457
Total liabilities	17,347	14,190
Level 3 | Series B preferred shares forward contracts
Liabilities:
Derivative contracts	15,890	14,190
Level 3 | Money market funds
Assets:
Cash equivalents	0	0
Level 3 | U.S. corporate bonds
Assets:
Marketable securities	0	0
Level 3 | Foreign corporate bonds
Assets:
Marketable securities	$ 0	$ 0

Fair Value of Financial Asset_4

Fair Value of Financial Assets and Liabilities - Roll Forward of Aggregate Fair Value Determined by Level 3 Inputs (Details) - USD ($)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Series B preferred shares forward contracts
Roll forward of aggregate fair value determined by Level 3 inputs
Balance at beginning of period	$ 14,190,000
Change in fair value	1,700,000
Balance at end of period	15,890,000	$ 0
Series A preferred shares derivative liability
Roll forward of aggregate fair value determined by Level 3 inputs
Balance at beginning of period		37,690,000
Change in fair value		5,131,000
Partial settlement of derivative liability		(42,821,000)
Balance at end of period	$ 0	$ 0

Fair Value of Financial Asset_5

Fair Value of Financial Assets and Liabilities - Narrative (Details)	Jun. 30, 2021	Jan. 04, 2021USD ($)
Level 3
Fair Value, Assets and Liabilities
FDA approval time frame for valuation	30 months
Level 3 | Measurement input, discount rate
Fair Value, Assets and Liabilities
Contingent value right liability measurement input	0.07
Level 3 | Measurement input, FDA approval
Fair Value, Assets and Liabilities
Contingent value right liability measurement input	0.10
Kleo
Fair Value, Assets and Liabilities
Amount received per contingent value right upon regulatory approval		$ 1
Contingent value right term period		30 months
Maximum amount payable for contingent value rights		$ 17,300,000
Fair value of contingent value right		$ 1,457,000

Balance Sheet Components - Cash

Balance Sheet Components - Cash and Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Cash and Restricted Cash
Cash and cash equivalents	$ 306,267	$ 132,149
Restricted cash (included in other current assets)	1,132	1,082
Restricted cash (included in other assets)	750	1,000
Cash, cash equivalents and restricted cash in the statement of cash flows	$ 308,149	$ 134,231	$ 263,862	$ 317,727

Balance Sheet Components - Inve

Balance Sheet Components - Inventories (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Inventories
Raw materials	$ 0	$ 931
Work-in-process	94,324	33,266
Finished goods	3,462	5,366
Total inventories	97,786	39,563
Less noncurrent inventories	33,728	0
Total inventories classified as current	$ 64,058	$ 39,563

Balance Sheet Components - Prep

Balance Sheet Components - Prepaid Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Prepaid Expenses
Prepaid clinical trial costs	$ 24,108	$ 21,173
Prepaid manufacturing	2,919	36,040
Prepaid commercial costs	19,326	16,448
Other prepaid expenses	2,518	3,021
Other current assets	$ 48,871	$ 76,682

Balance Sheet Components - Accr

Balance Sheet Components - Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Accrued Expense and Other Current Liabilities
Accrued development milestones	$ 500	$ 667
Accrued employee compensation and benefits	26,964	29,447
Accrued clinical trial costs	29,972	19,887
Accrued commercialization and other professional fees	27,273	6,336
Accrued sales discounts and allowances	104,668	73,155
Current obligation to perform R&D services	37,466	846
Other accrued expenses and other current liabilities	49,787	36,292
Accrued expenses and other current liabilities	$ 276,630	$ 166,630

Business Acquisition (Details)

Business Acquisition (Details) - USD ($)	Jan. 04, 2021	Jun. 30, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Equity method investment		$ 0	$ 1,176,000
Kleo
Business Acquisition [Line Items]
Fair value of consideration transferred	$ 20,043,000
Issuance of shares	115,836
Amount received per contingent value right upon regulatory approval	$ 1
Contingent value right term period	30 months
Maximum amount payable for contingent value rights	$ 17,300,000
Holdbacks for indemnification claims	950,000
Fair value of contingent value right	$ 1,457,000
Post-transaction ownership percentage	100.00%
Fair value of existing interest	$ 6,437,000
Gain resulting from remeasurement of fair value of existing interest		$ 5,261,000
Amounts recorded:
Net working capital	573,000
Property, plant and equipment, net	1,257,000
Intangible assets, in progress research and development	18,400,000
Debt assumed	1,577,000
Goodwill	$ 1,390,000
Kleo
Business Acquisition [Line Items]
Ownership percentage			41.90%
Equity method investment			$ 1,176,000

Liability Related to Sale of _3

Liability Related to Sale of Future Royalties, net - Narrative (Details) $ / shares in Units, $ in Thousands	1 Months Ended			2 Months Ended	3 Months Ended	6 Months Ended		8 Months Ended
	Mar. 31, 2021USD ($)	Aug. 31, 2020USD ($)unit_of_accounting	Jun. 30, 2018USD ($)unit_of_accounting$ / sharesshares	Feb. 29, 2020USD ($)	Jun. 30, 2021USD ($)	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Mar. 31, 2021USD ($)
Liability For Sale of Future Royalties [Line Items]
Proceeds from sale of common stock	$ 229,500			$ 282,833		$ 308,743	$ 283,333
RPI Agreement
Liability For Sale of Future Royalties [Line Items]
Units of accounting related to consideration received | unit_of_accounting			2
Transaction consideration allocated to liability			$ 106,047
Transaction consideration allocated to equity			43,953
Transaction costs			377
2018 RPI Funding Agreement
Liability For Sale of Future Royalties [Line Items]
Proceeds from royalty agreement			$ 100,000
Effective interest rate (percent)					27.00%	27.00%
RPI Purchase Agreement
Liability For Sale of Future Royalties [Line Items]
Common stock issued (shares) | shares			1,111,111
Common stock sold, price per share (in dollars per share) | $ / shares			$ 45
Proceeds from sale of common stock			$ 50,000
2020 RPI Funding Agreement
Liability For Sale of Future Royalties [Line Items]
Units of accounting related to consideration received | unit_of_accounting		2
Transaction consideration allocated to liability		$ 147,876
Transaction costs		400
Effective interest rate (percent)					6.00%	6.00%
Sales-based participation rights sold, value		$ 250,000
Percentage of global net sales of products containing zavegepant for basis of participation rights		0.03%
Percentage of global net sales of products containing rimegepant for basis of participation rights		0.004%
Proceeds from sale of sales-based participation rights	$ 100,000	$ 150,000
Period from closing for repurchase if change of control consummated		180 days
Buy-Back option factor		2
Success-based milestone payments based on first zavegepant regulatory approval, relative to funded amount		1.9
Time period for success-based milestone payments		10 years
Proceeds allocated to obligation to perform contractual services		$ 2,124						$ 102,124
Reduction in research and development expenses					$ 10,016	$ 10,205
2020 RPI Funding Agreement | Minimum
Liability For Sale of Future Royalties [Line Items]
Success-based milestone payments based on regulatory approval, relative to funded amount		0.6
2020 RPI Funding Agreement | Maximum
Liability For Sale of Future Royalties [Line Items]
Success-based milestone payments based on regulatory approval, relative to funded amount		2.95

Liability Related to Sale of _4

Liability Related to Sale of Future Royalties, net - Activity within Liability Account (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Liability related to sales of future royalties
Interest expense on liability related to sale of future royalties	$ 14,499	$ 11,570	$ 28,007	$ 19,995
2018 and 2020 RPI Funding Agreements
Liability related to sales of future royalties
Liability related to sale of future royalties - beginning balance			335,282	144,111
Royalty revenues payable to RPI			(3,419)	(228)
Interest expense on liability related to sale of future royalties			28,007	19,995
Liability related to sale of future royalties - ending balance	$ 359,870	$ 163,878	$ 359,870	$ 163,878

Mandatorily Redeemable Prefer_3

Mandatorily Redeemable Preferred Shares, net - Narrative (Details) $ / shares in Units, $ in Thousands	Aug. 07, 2020$ / sharesshares	Apr. 30, 2019USD ($)closing$ / sharesshares	Jun. 30, 2021USD ($)shares	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)shares	Jun. 30, 2020USD ($)	Dec. 31, 2020shares
Mandatorily Redeemable Preferred Shares
Fee to be recognized for nonissuance of shares				$ 3,000
Interest expense			$ 8,042		$ 6,993	$ 15,985	$ 12,554
Series A preferred shares
Mandatorily Redeemable Preferred Shares
Number of shares sold in transaction (in shares) | shares		2,495
Issuance price per share (in dollars per share) | $ / shares		$ 50,100
Gross proceeds from transaction		$ 125,000
Payment for priority review voucher		$ 105,000
Number of additional closings per share agreement, maximum | closing		3
Aggregate value of additional closings available per share agreement		$ 75,000
Maximum fee per share agreement for nonissuance of shares		$ 3,000
Redemption relative to original purchase price upon optional redemption		2
Annual interest rate upon default of redemption (percent)		18.00%
Redemption relative to original purchase price upon required redemption			2			2
Effective interest rate (percent)			20.00%			20.00%
Interest expense			$ 7,677		6,993	$ 15,620	12,554
Partial settlement of derivative liability					$ 42,821		$ 42,821
Mandatorily redeemable shares outstanding (in shares) | shares			2,183			2,183		2,495
Series A preferred shares | Change of control
Mandatorily Redeemable Preferred Shares
Redemption relative to original purchase price upon required redemption		2
Series B preferred shares
Mandatorily Redeemable Preferred Shares
Number of shares sold in transaction (in shares) | shares	3,992
Issuance price per share (in dollars per share) | $ / shares	$ 50,100,000
Effective interest rate (percent)			8.00%			8.00%
Interest expense			$ 365			$ 365
Mandatorily redeemable shares issued (in shares) | shares			702			702		0
Mandatorily redeemable shares outstanding (in shares) | shares			702			702		0

Mandatorily Redeemable Prefer_4

Mandatorily Redeemable Preferred Shares, net - Activity Within the Preferred Share Liability (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Mandatorily Redeemable Preferred Shares [Roll Forward]
Interest expense on mandatorily redeemable preferred shares	$ 8,042	$ 6,993	$ 15,985	$ 12,554
Net balance at period end	133,091		133,091		$ 111,591
Series A preferred shares
Mandatorily Redeemable Preferred Shares [Roll Forward]
Beginning balance, gross			174,264	103,864
Partial settlement of derivative liability		42,821		42,821
Interest expense recognized, excluding transaction cost amortization			15,599	12,532
Redemption of Series A preferred shares			(31,250)
Interest expense on mandatorily redeemable preferred shares	7,677	6,993	15,620	12,554
Ending balance, gross	158,613	159,217	158,613	159,217
Less: unamortized transaction costs	(152)	(196)	(152)	(196)
Net balance at period end	158,461	$ 159,021	158,461	$ 159,021
Series B preferred shares
Mandatorily Redeemable Preferred Shares [Roll Forward]
Beginning balance, gross			0
Interest expense on mandatorily redeemable preferred shares	365		365
Issuance of Series B preferred shares			36,765
Ending balance, gross	$ 37,130		$ 37,130

Shareholders' Equity (Deficit_2

Shareholders' Equity (Deficit) - Changes in Shareholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ (278,155)	$ (392,189)	$ 121,958	$ (7,424)	$ (392,189)	$ (7,424)
Issuance of common shares as part of acquisition		10,673
Issuance of common shares as payment for assets		10,243
Issuance of common shares, net of offering costs		308,243		282,833
Issuance of common shares under equity incentive plan		1,382	11,748	2,607
Issuance of common shares under equity incentive plan and employee share purchase plan	7,261
Non-cash share-based compensation expense	25,586	48,726	11,762	16,879
Net loss	(211,159)	(265,328)	(180,934)	(172,937)	(476,487)	(353,871)
Other comprehensive income (loss)	(129)	95	0		(34)	0
Ending balance	(456,596)	(278,155)	(35,466)	121,958	(456,596)	(35,466)
Biohaven Shareholders' Equity (Deficit)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(275,976)	(390,370)	121,958	(7,424)	(390,370)	(7,424)
Issuance of common shares as part of acquisition		10,673
Issuance of common shares as payment for assets		10,243
Issuance of common shares, net of offering costs		308,243		282,833
Issuance of common shares under equity incentive plan		1,382	11,748	2,607
Issuance of common shares under equity incentive plan and employee share purchase plan	7,261
Non-cash share-based compensation expense	25,586	48,726	11,762	16,879
Net loss	(210,619)	(264,968)	(180,934)	(172,937)
Other comprehensive income (loss)	(129)	95
Ending balance	(453,877)	(275,976)	(35,466)	121,958	(453,877)	(35,466)
Common Shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 1,604,021	$ 1,249,547	$ 1,175,139	$ 881,426	$ 1,249,547	$ 881,426
Beginning balance (in shares)	65,066,468	60,436,876	58,387,948	52,385,283	60,436,876	52,385,283
Issuance of common shares as part of acquisition		$ 10,673
Issuance of common shares as part of acquisition (in shares)		115,836
Issuance of common shares as payment for assets		$ 10,243
Issuance of common shares as payment for assets (in shares)		110,998
Issuance of common shares, net of offering costs		$ 308,243		$ 282,833
Issuance of common shares, net of offering costs (in shares)		4,037,204		5,555,554
Issuance of common shares under equity incentive plan		$ 25,315	$ 23,866	$ 10,880
Issuance of common shares under equity incentive plan (shares)		365,554	1,137,617	447,111
Issuance of common shares under equity incentive plan and employee share purchase plan	$ 14,173
Issuance of common shares under equity incentive plan and employee share purchase plan (in shares)	173,990
Ending balance	$ 1,618,194	$ 1,604,021	$ 1,199,005	$ 1,175,139	$ 1,618,194	$ 1,199,005
Ending balance (in shares)	65,240,458	65,066,468	59,525,565	58,387,948	65,240,458	59,525,565
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 123,731	$ 98,938	$ 92,129	$ 83,523	$ 98,938	$ 83,523
Issuance of common shares under equity incentive plan		(23,933)	(12,118)	(8,273)
Issuance of common shares under equity incentive plan and employee share purchase plan	(6,912)
Non-cash share-based compensation expense	25,586	48,726	11,762	16,879
Ending balance	142,405	123,731	91,773	92,129	142,405	91,773
Accumulated Deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(2,004,137)	(1,739,169)	(1,145,310)	(972,373)	(1,739,169)	(972,373)
Net loss	(210,619)	(264,968)	(180,934)	(172,937)
Ending balance	(2,214,756)	(2,004,137)	(1,326,244)	(1,145,310)	(2,214,756)	(1,326,244)
Accumulated Other Comprehensive Income
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	409	314	0	0	314	0
Other comprehensive income (loss)	(129)	95
Ending balance	280	409	0	0	280	0
Non-controlling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(2,179)	(1,819)	0	0	(1,819)	0
Net loss	(540)	(360)
Ending balance	$ (2,719)	$ (2,179)	$ 0	$ 0	$ (2,719)	$ 0

Shareholders' Equity (Deficit_3

Shareholders' Equity (Deficit) - Narrative (Details) $ / shares in Units, $ in Thousands

Jan. 01, 2021USD ($)shares

Mar. 31, 2021USD ($)$ / sharesshares

Jan. 31, 2021USD ($)shares

Sep. 30, 2020USD ($)$ / sharesshares

Feb. 29, 2020USD ($)shares

Jan. 31, 2020USD ($)$ / sharesshares

Feb. 29, 2020USD ($)

Jun. 30, 2021USD ($)shares

Mar. 31, 2021USD ($)$ / sharesshares

Jun. 30, 2020USD ($)

Mar. 31, 2020shares

Jun. 30, 2021USD ($)shares

Jun. 30, 2020USD ($)

Jan. 04, 2021shares

Dec. 31, 2020USD ($)

Sale of Stock [Line Items]

Proceeds from sale of common stock

$ 229,500

$ 282,833

$ 308,743

$ 283,333

Payment for license agreement

0

21,500

Issuance of common shares as payment for assets

$ 10,243

Equity Distribution Agreement aggregate amount

$ 400,000

Noncontrolling interest

$ 540

$ 0

$ 900

$ 0

Kleo

Sale of Stock [Line Items]

Ownership percentage

41.90%

Yale University | License agreement | Yale MoDE Agreement

Sale of Stock [Line Items]

Payment for license agreement

$ 1,000

Issuance of common shares as payment for assets (in shares) | shares

11,668

Issuance of common shares as payment for assets

$ 1,000

Moda Pharmaceuticals LLC | License agreement | Moda Agreement

Sale of Stock [Line Items]

Payment for license agreement

$ 2,700

Issuance of common shares as payment for assets (in shares) | shares

37,836

Issuance of common shares as payment for assets

$ 3,243

Common Shares

Sale of Stock [Line Items]

Common stock issued (shares) | shares

4,037,204

5,555,554

Issuance of common shares as part of acquisition (in shares) | shares

115,836

Issuance of common shares as payment for assets (in shares) | shares

110,998

Issuance of common shares as payment for assets

$ 10,243

Kleo

Sale of Stock [Line Items]

Shares of common stock exchanged for each share of acquiree | shares

0.007

BioShin 2020 Equity Incentive Plan

Sale of Stock [Line Items]

Requisite service period of award (in years)

3 years

Minimum

Sale of Stock [Line Items]

Requisite service period of award (in years)

3 years

Maximum

Sale of Stock [Line Items]

Requisite service period of award (in years)

4 years

Series A preferred shares | Minimum

Sale of Stock [Line Items]

Preferred shares call and put options execution multiple following change of control

2.5

Series A preferred shares | Maximum

Sale of Stock [Line Items]

Preferred shares call and put options execution multiple following change of control

3.5

Series A-2 preferred stock | Artizan Biosciences Inc

Sale of Stock [Line Items]

Preferred shares paid (in shares) | shares

61,494

Preferred shares paid

$ 6,000

Preferred shares received (in shares) | shares

34,472,031

Public offering

Sale of Stock [Line Items]

Common stock issued (shares) | shares

2,686,409

4,830,917

Issuance price per share (in dollars per share) | $ / shares

$ 76

$ 51.75

$ 76

Proceeds from sale of common stock

$ 199,500

$ 245,877

Underwriting discounts and commissions

4,167

3,623

Other offering expenses

$ 500

$ 500

Over-allotment option

Sale of Stock [Line Items]

Common stock issued (shares) | shares

402,961

724,637

Proceeds from sale of common stock

$ 30,000

$ 36,956

Underwriting discounts and commissions

$ 625

$ 543

Equity Distribution Agreement

Sale of Stock [Line Items]

Common stock issued (shares) | shares

0

939,328

Proceeds from sale of common stock

$ 78,743

BioShin Preferred Shares | Series A preferred shares

Sale of Stock [Line Items]

Preferred stock issued and sold (in shares) | shares

15,384,613

Shares issued price per share | $ / shares

$ 3.90

Proceeds from shares issued

$ 60,000

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2021	Jun. 30, 2020
AOCI [Roll Forward]
Beginning of period balance		$ (390,370,000)
End of period balance	$ (453,877,000)	(453,877,000)
Accumulated other comprehensive income
AOCI [Roll Forward]
Beginning of period balance	409,000	314,000
Other comprehensive income (loss)	(129,000)	(34,000)
End of period balance	280,000	280,000	$ 0
Net unrealized investment gains (losses)
AOCI [Roll Forward]
Beginning of period balance	(43,000)	(125,000)
Other comprehensive income (loss)	73,000	136,000
Amounts reclassified from accumulated other comprehensive income	0	19,000
Other comprehensive income (loss)	73,000	155,000
End of period balance	30,000	30,000
Foreign currency translation adjustments
AOCI [Roll Forward]
Beginning of period balance	452,000	439,000
Other comprehensive income (loss)	(202,000)	(189,000)
End of period balance	$ 250,000	$ 250,000

Share-Based Compensation - Non-

Share-Based Compensation - Non-Cash Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share-Based Compensation
Total non-cash share-based compensation expense	$ 25,586	$ 11,762	$ 74,312	$ 28,641
Less: Share-based compensation expense attributable to non-controlling interests	540	0	900	0
Share-based compensation expense attributable to Biohaven Pharmaceutical Holding Company Ltd.	25,046	11,762	$ 73,412	28,641
Minimum
Share-Based Compensation
Requisite service period of award (in years)			3 years
Maximum
Share-Based Compensation
Requisite service period of award (in years)			4 years
Research and development expenses
Share-Based Compensation
Total non-cash share-based compensation expense	9,273	6,426	$ 29,331	12,677
Selling, general and administrative expenses
Share-Based Compensation
Total non-cash share-based compensation expense	$ 16,313	$ 5,336	$ 44,981	$ 15,964

Share-Based Compensation - Stoc

Share-Based Compensation - Stock Options (Details) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2021USD ($)$ / sharesshares
Number of shares
Outstanding at beginning of period (in shares)	7,545,907
Granted (in shares)	1,252,530
Exercised (in shares)	(153,847)
Forfeited (in shares)	(70,790)
Outstanding at end of period (in shares)	8,573,800
Options exercisable (in shares)	5,406,077
Options vested and expected to vest (in shares)	8,573,800
Weighted Average Exercise Price
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 28.21
Granted (in dollars per share) | $ / shares	82.53
Exercised (in dollars per share) | $ / shares	35.05
Forfeited (in dollars per share) | $ / shares	55.98
Outstanding at end of period (in dollars per share) | $ / shares	35.78
Options exercisable (in dollars per share) | $ / shares	25.91
Options vested and expected to vest (in dollars per share) | $ / shares	$ 35.78
Weighted Average Contractual Term and Aggregate Intrinsic Value
Weighted average remaining contractual term of options outstanding (in years)	6 years 11 months 1 day
Weighted average remaining contractual term of options exercisable (in years)	6 years 2 months 1 day
Weighted average remaining contractual term of options vested and expected to vest (in years)	6 years 11 months 1 day
Aggregate intrinsic value of options outstanding | $	$ 525,563
Aggregate intrinsic value of options exercisable | $	384,734
Aggregate intrinsic value of options vested and expected to vest | $	$ 525,563
Additional Disclosures
Unvested options expected to vest (in shares)	3,167,723
Stock options
Additional Disclosures
Share-based award term (in years)	10 years
Total unrecognized compensation cost | $	$ 76,622
Weighted average period for recognition of compensation cost	1 year 10 months 13 days
Stock options | Minimum
Additional Disclosures
Share-based award vesting period (in years)	3 years
Stock options | Maximum
Additional Disclosures
Share-based award vesting period (in years)	4 years

Share-Based Compensation - Rest

Share-Based Compensation - Restricted Share Units (Details) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2021USD ($)$ / sharesshares
Additional Disclosures
Number of common shares received per vested RSU	1
Restricted Share Units
Number of shares
Unvested outstanding, beginning (in shares)	467,160
Granted (in shares)	1,093,250
Forfeited (in shares)	(25,631)
Vested (in shares)	(355,308)
Unvested outstanding, ending (in shares)	1,179,471
Weighted Average Grant Date Fair Value
Unvested outstanding, beginning (in dollars per share) | $ / shares	$ 56
Granted (in dollars per share) | $ / shares	82.86
Forfeited (in dollars per share) | $ / shares	75.23
Vested (in dollars per share) | $ / shares	72.74
Unvested outstanding, ending (in dollars per share) | $ / shares	$ 75.43
Additional Disclosures
Total unrecognized compensation cost | $	$ 74,781
Weighted average period for recognition of compensation cost	2 years 4 months 28 days
Fair value of RSUs vested | $	$ 25,846

Net Loss Per Share - Calculatio

Net Loss Per Share - Calculation of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator:
Net loss	$ (211,159)	$ (265,328)	$ (180,934)	$ (172,937)	$ (476,487)	$ (353,871)
Net loss attributable to non-controlling interests	(540)		0		(900)	0
Net loss attributable to Biohaven Pharmaceutical Holding Company Ltd.	$ (210,619)		$ (180,934)		$ (475,587)	$ (353,871)
Denominator:
Weighted average common shares outstanding - basic (shares)	65,112,179		58,742,329		63,584,932	57,577,384
Weighted average common shares outstanding - diluted (shares)	65,112,179		58,742,329		63,584,932	57,577,384
Net loss per share attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd. - basic (in dollars per share)	$ (3.23)		$ (3.08)		$ (7.48)	$ (6.15)
Net loss per share attributable to common shareholders of Biohaven Pharmaceutical Holding Company Ltd. - diluted (in dollars per share)	$ (3.23)		$ (3.08)		$ (7.48)	$ (6.15)

Net Loss Per Share - Antidiluti

Net Loss Per Share - Antidilutive Securities Excluded from Computation of Net Loss per Share (Details) - shares	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Securities excluded from computation of diluted net loss per share
Anti-dilutive securities excluded from calculation of diluted net loss per share	9,860,022	8,705,197
Options 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	8,573,800	8,120,648
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	106,751	106,751
Restricted share units
Securities excluded from computation of diluted net loss per share
Anti-dilutive securities excluded from calculation of diluted net loss per share	1,179,471	477,798

License and Other Agreements -

License and Other Agreements - Yale University Agreements (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended	6 Months Ended
	Jan. 31, 2021	May 31, 2019	Sep. 30, 2013	Mar. 31, 2021	Jun. 30, 2021	Jun. 30, 2020
License and other agreements
Payment for license agreement					$ 0	$ 21,500
Issuance of common shares as payment for assets				$ 10,243
Yale University | Yale Arrangement
License and other agreements
Issuance of common shares, net of offering costs (in shares)			250,000
Right to purchase securities in specified future equity offering (as a percent)			10.00%
Milestone payment to be paid upon regulatory achievement		$ 2,000
Minimum annual royalty payment to be paid upon sale of product		$ 1,000
Yale University | Yale MoDE Agreement
License and other agreements
Minimum annual royalty payment to be paid upon sale of product	$ 1,000
Eligible development milestone payments	800
Eligible commercial milestone payments	$ 2,950
Initial term of agreement (in years)	20 years
Yale University | Yale MoDE Agreement | License agreement
License and other agreements
Payment for license agreement	$ 1,000
Issuance of common shares as payment for assets (in shares)	11,668
Issuance of common shares as payment for assets	$ 1,000

License and Other Agreements _2

License and Other Agreements - ALS Biopharma Agreement (Details)	1 Months Ended	3 Months Ended		6 Months Ended
	Aug. 31, 2015USD ($)claimprodrug	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)
License and other agreements
Research and development expense		$ 77,428,000	$ 42,425,000	$ 184,539,000	$ 98,495,000
ALS Biopharma Agreement | Collaborative arrangement
License and other agreements
Number of prodrugs of glutamate modulating agents | prodrug	300
Milestone payment to be paid upon regulatory achievement	$ 3,000,000
Milestone payment to be paid for subsequently developed products	$ 1,000,000
Number of claims | claim	1
Research and development expense		$ 0	$ 0	$ 0	$ 0

License and Other Agreements _3

License and Other Agreements - Catalent Agreement for Rimegepant (Details) - Collaborative arrangement - Catalent Agreement - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Jan. 31, 2018	Jun. 30, 2020	Mar. 31, 2020	Feb. 27, 2020
License and other agreements
Last patent right expiration period (in years)	10 years
Automatic extension period (in years)	1 year
Milestone payments		$ 750	$ 750
Maximum
License and other agreements
Payment required due to achievement of milestone				$ 1,500
Required milestone payments capitalized to intangible asset			$ 1,500

License and Other Agreements _4

License and Other Agreements - Rutgers Agreement (Details) - Rutgers - Rutgers Agreement $ in Thousands	1 Months Ended	6 Months Ended
	Jun. 30, 2016USD ($)	Jun. 30, 2021USD ($)
License and other agreements
Milestone payment to be paid upon regulatory achievement	$ 825
Change of control fee	0.0030
Fair value of derivative liability	$ 0
Extension of due diligence requirements (in years)		1 year
Amount of payment subject to due diligence extension		$ 500
Last patent right expiration period (in years)		10 years
Minimum
License and other agreements
Guaranteed royalties	100
Consideration payable upon change-of-control event	$ 100

License and Other Agreements _5

License and Other Agreements - BMS Agreement and Amendment (Details) $ in Thousands

Feb. 27, 2020USD ($)

Nov. 30, 2020USD ($)

Aug. 31, 2020USD ($)

Mar. 31, 2018USD ($)

Jul. 31, 2016USD ($)product

Jun. 30, 2021USD ($)

Dec. 31, 2020USD ($)

Sep. 30, 2020USD ($)

Jun. 30, 2020USD ($)

Mar. 31, 2020USD ($)

Jun. 30, 2021USD ($)

Jun. 30, 2020USD ($)

Mar. 31, 2021USD ($)

Dec. 31, 2019USD ($)

Mar. 31, 2019USD ($)

Dec. 31, 2018USD ($)

BMS Agreement

License and other agreements

Upfront payment under the BMS Amendment

$ 5,000

$ 50,000

Maximum obligated payment for each licensed product to achieve commercial milestone

$ 22,500

BMS Agreement | Collaborative arrangement

License and other agreements

Payment required due to achievement of milestone

$ 40,000

Milestone payments

$ 5,000

$ 6,000

$ 20,000

$ 20,000

Accrued expense for payment due upon commencement of Phase 1 clinical trial

$ 2,000

Accrued expense for payment due upon commencement of Phase 2 clinical trial

$ 4,000

Accrued expense for payment due upon commencement of Phase 3 clinical trial

$ 6,000

Payment required due to commencement of Phase 1 clinical trial

2,000

Payment required due to commencement of Phase 2 clinical trial

$ 4,000

Accrued expense for payment due following regulatory approval

$ 5,000

Royalty expense

$ 9,293

$ 860

$ 13,678

$ 975

BMS Agreement | Collaborative arrangement | Maximum

License and other agreements

Milestone payment to be paid upon regulatory achievement

$ 127,500

Milestone payment to be paid for any product other than rimegepant

74,500

Commercial milestone payment to be paid

$ 150,000

BMS Agreement | Collaborative arrangement | Minimum

License and other agreements

Number of licensed products | product

1

November 2020 BMS Amendment | Collaborative arrangement

License and other agreements

Commercial milestone payment to be paid

$ 150,000

Net sales threshold for milestone (percent)

10.00%

Development milestone payment to be paid

$ 17,500

License and Other Agreements _6

License and Other Agreements - AstraZeneca Agreements (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended	6 Months Ended
	Sep. 30, 2018	Oct. 31, 2016	Mar. 31, 2021	Jun. 30, 2021	Jun. 30, 2020
License and other agreements
Payment for license agreement				$ 0	$ 21,500
Issuance of common shares as payment for assets			$ 10,243
AstraZeneca | License agreement
License and other agreements
Payment for license agreement	$ 3,000
Issuance of common shares as payment for assets (in shares)	109,523
Issuance of common shares as payment for assets	$ 4,080
Milestone payment due upon achievement of specified regulatory and commercial milestones	55,000
Milestone payment due upon achievement of specified sales-based milestones	$ 50,000
AstraZeneca | Collaborative arrangement | Maximum
License and other agreements
Milestone payment to be paid upon regulatory achievement		$ 30,000
Milestone payment to be paid for any product other than Rett syndrome		60,000
Commercial milestone payment to be paid		$ 120,000
Agreement term after first commercial sale		10 years

License and Other Agreements _7

License and Other Agreements - Revenue Participation Rights (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Aug. 31, 2020
License and other agreements
Interest expense on liability related to sale of future royalties		$ 14,499,000	$ 11,570,000	$ 28,007,000	$ 19,995,000
2018 RPI Funding Agreement
License and other agreements
Proceeds from royalty agreement	$ 100,000,000
Interest expense on liability related to sale of future royalties		12,049,000		23,468,000
Payments under funding agreement		920,000	0	1,656,000	0
2020 RPI Funding Agreement
License and other agreements
Interest expense on liability related to sale of future royalties		2,450,000	0	4,539,000	0
Payments under funding agreement		$ 175,000	$ 0	$ 315,000	$ 0
Sales-based participation rights sold, value						$ 250,000,000
Revenue Participation Right, tranche one | 2018 RPI Funding Agreement
License and other agreements
Participation rate for revenue participation right (percent)	2.10%
Revenue Participation Right, tranche one | 2018 RPI Funding Agreement | Maximum
License and other agreements
Annual global net sales threshold for revenue participation right	$ 1,500,000,000
Revenue Participation Right, tranche two | 2018 RPI Funding Agreement
License and other agreements
Participation rate for revenue participation right (percent)	1.50%

License and Other Agreements _8

License and Other Agreements - Fox Chase Chemical Diversity Center Agreement (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended				6 Months Ended
	Nov. 30, 2020	May 31, 2019	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
License and other agreements
Issuance of common shares, net of offering costs				$ 308,243		$ 282,833
Research and development expense			$ 77,428		$ 42,425		$ 184,539	$ 98,495
FCCDC Agreement | Collaborative arrangement
License and other agreements
Common stock issued (shares)		100,000
Issuance of common shares, net of offering costs		$ 5,646
Development milestone payment to be paid		4,500
Development milestone payments to be paid per each additional NDA filing		$ 1,000
Performance milestone payment to be paid	$ 3,800
Time period for payment of performance milestone	30 months
Research and development expense			$ 509		$ 450		$ 1,321	$ 1,405
FCCDC Agreement | Collaborative arrangement | Minimum
License and other agreements
Earned royalty payment per agreement (percent)	0.00%
FCCDC Agreement | Collaborative arrangement | Maximum
License and other agreements
Earned royalty payment per agreement (percent)	10.00%
FCCDC Warrants
License and other agreements
Number of securities called by warrants (shares)		100,000
Exercise price of warrants (in dollars per share)		$ 56.46

License and Other Agreements _9

License and Other Agreements - Sosei Heptares (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended			6 Months Ended
	Nov. 30, 2020	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
License and other agreements
Payment for license agreement					$ 0	$ 21,500
Issuance of common shares as payment for assets			$ 10,243
Research and development expense		$ 77,428		$ 42,425	184,539	$ 98,495
Sosei Heptares | Collaborative arrangement
License and other agreements
Eligible milestone payment per agreement upon specified performance and regulatory milestones	$ 370,000
Initial term of agreement (in years)	10 years
Notice period to terminate agreement during research term	180 days
Notice period to terminate agreement following research term	90 days
Counterparty notice period after research term to terminate agreement	30 days
Counterparty continuous period for development activities	365 days
Counterparty notice period for notification	3 months
Research and development expense		$ 2,868			$ 3,485
Sosei Heptares | Collaborative arrangement | Minimum
License and other agreements
Earned royalty payment per agreement (percent)	0.00%
Sosei Heptares | Collaborative arrangement | Maximum
License and other agreements
Earned royalty payment per agreement (percent)	10.00%
Sosei Heptares | Collaborative arrangement | License agreement
License and other agreements
Payment for license agreement	$ 5,000
Issuance of common shares as payment for assets (in shares)	54,617
Issuance of common shares as payment for assets	$ 4,858

License and Other Agreements_10

License and Other Agreements - Artizan Biosciences Inc (Details) - Artizan Biosciences Inc $ in Thousands	Dec. 31, 2020USD ($)shares
License and other agreements
Preferred shares acquired | shares	34,472,031
Value of preferred shares acquired	$ 6,000
Collaborative arrangement | Minimum
License and other agreements
Option price	4,000
Collaborative arrangement | Maximum
License and other agreements
Option price	$ 8,000

License and Other Agreements_11

License and Other Agreements - Moda Pharmaceuticals LLC (Details) - USD ($) $ in Thousands	Jan. 01, 2021	Mar. 31, 2021	Jun. 30, 2021	Jun. 30, 2020
License and other agreements
Payment for license agreement			$ 0	$ 21,500
Issuance of common shares as payment for assets		$ 10,243
Moda Pharmaceuticals LLC | Moda Agreement
License and other agreements
Eligible development milestone payments	$ 81,612
Eligible commercial milestone payments	$ 30,171
Initial term of agreement (in years)	4 years
Moda Pharmaceuticals LLC | Moda Agreement | License agreement
License and other agreements
Payment for license agreement	$ 2,700
Issuance of common shares as payment for assets (in shares)	37,836
Issuance of common shares as payment for assets	$ 3,243

License and Other Agreements_12

License and Other Agreements - Reliant Glycosciences LLC (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Jul. 31, 2021	Mar. 31, 2021
License and other agreements
Issuance of common shares as payment for assets		$ 10,243
Reliant Glycosciences, LLC | Reliant Agreement | Subsequent event
License and other agreements
Eligible development milestone payments	$ 36,500
Reliant Glycosciences, LLC | License agreement | Subsequent event
License and other agreements
Issuance of common shares as payment for assets	$ 3,686

Debt - Narrative (Details)

Debt - Narrative (Details) - Senior secured debt	Aug. 31, 2020USD ($)
Sixth Street Financing Agreement
Liability For Sale of Future Royalties [Line Items]
Credit facility capacity	$ 500,000,000
Sixth Street Financing - term loan
Liability For Sale of Future Royalties [Line Items]
Principal amount	275,000,000
Sixth Street Financing - delayed draw term loans
Liability For Sale of Future Royalties [Line Items]
Principal amount	$ 225,000,000

Debt - Summary of borrowings (D

Debt - Summary of borrowings (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2021USD ($)
Liability For Sale of Future Royalties [Line Items]
Debt principal	$ 285,127
Unamortized debt discount and issuance costs	(10,989)
Less: current portion	0
Long-term debt	274,138
Paid-in-kind interest	5,649
Sixth Street Financing - term loan | Senior secured debt
Liability For Sale of Future Royalties [Line Items]
Debt principal	$ 285,127
Contractual interest rate (percent)	10.00%