0001628280-21-008918 | 10-Q | XBRL Viewer | Esperion Therapeutics INC

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Cover Page - shares	3 Months Ended
Cover Page - shares	Mar. 31, 2021	May 01, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-35986
Entity Registrant Name	Esperion Therapeutics, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	26-1870780
Entity Address, Address Line One	3891 Ranchero Drive, Suite 150
Entity Address, City or Town	Ann Arbor
Entity Address, State or Province	MI
Entity Address, Postal Zip Code	48108
City Area Code	734
Local Phone Number	887-3903
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	ESPR
Security Exchange Name	NASDAQ
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		28,192,134
Entity Central Index Key	0001434868
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Amendment Flag	false

Condensed Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 217,939	$ 304,962
Prepaid clinical development costs	443	844
Inventories	20,030	16,136
Other prepaid and current assets	34,163	23,954
Total current assets	272,575	345,896
Property and equipment, net	1,123	1,276
Right of use operating lease assets	4,852	6,030
Intangible assets	56	56
Total assets	278,606	353,258
Current liabilities:
Accounts payable	30,342	51,975
Accrued clinical development costs	7,549	7,663
Other accrued liabilities	48,766	24,790
Revenue interest liability	6,353	5,392
Deferred revenue from collaborations	2,543	1,662
Operating lease liabilities	2,340	2,587
Total current liabilities	97,893	94,069
Convertible notes, net of issuance costs	271,694	179,367
Revenue interest liability	174,603	171,212
Operating lease liabilities	2,520	3,454
Other long-term liabilities	1,290	1,290
Total liabilities	548,000	449,392
Commitments and contingencies (Note 5)
Stockholders’ equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized and no shares issued or outstanding as of March 31, 2021 and December 31, 2020	0	0
Common stock, $0.001 par value; 120,000,000 shares authorized as of March 31, 2021 and December 31, 2020; 28,176,917 shares issued at March 31, 2021 and 27,910,366 shares issued at December 31, 2020	26	26
Additional paid-in capital	713,782	797,655
Treasury stock, at cost; 1,994,198 shares at March 31, 2021 and December 31, 2020	(54,998)	(54,998)
Accumulated deficit	(928,204)	(838,817)
Total stockholders’ deficit	(269,394)	(96,134)
Total liabilities and stockholders’ deficit	$ 278,606	$ 353,258

Condensed Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, authorized (in shares)	5,000,000	5,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, authorized (in shares)	120,000,000	120,000,000
Common stock, issued (in shares)	28,176,917	27,910,366
Treasury stock (in shares)	1,994,198	1,994,198

Condensed Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenues:
Total Revenues	$ 7,978	$ 1,840
Operating expenses:
Cost of goods sold	1,784	31
Research and development	27,954	34,702
Selling, general and administrative	61,064	41,553
Total operating expenses	90,802	76,286
Loss from operations	(82,824)	(74,446)
Interest expense	(8,125)	(4,171)
Other income, net	14	368
Net loss	$ (90,935)	$ (78,249)
Net loss per common share - basic and diluted (in dollars per share)	$ (3.50)	$ (2.84)
Weighted-average shares outstanding - basic and diluted (in shares)	25,991,817	27,519,229
Other comprehensive loss:
Unrealized loss on investments	$ 0	$ (14)
Comprehensive loss	(90,935)	(78,263)
Product sales, net
Revenues:
Total Revenues	6,350	858
Collaboration revenue
Revenues:
Total Revenues	$ 1,628	$ 982

Condensed Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjusted Balance	Common Stock	Common Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Additional Paid-In Capital	Additional Paid-In Capital Cumulative Effect, Period of Adoption, Adjustment	Additional Paid-In Capital Cumulative Effect, Period of Adoption, Adjusted Balance	Accumulated Deficit	Accumulated Deficit Cumulative Effect, Period of Adoption, Adjustment	Accumulated Deficit Cumulative Effect, Period of Adoption, Adjusted Balance	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Cumulative Effect, Period of Adoption, Adjusted Balance	Treasury Stock	Treasury Stock Cumulative Effect, Period of Adoption, Adjusted Balance
Beginning balance (in shares) at Dec. 31, 2019				27,497,911
Beginning balance at Dec. 31, 2019	$ 19,950			$ 27		$ 715,166			$ (695,266)			$ 23		$ 0
Increase (Decrease) in Stockholders' Equity
Exercise of stock options (in shares)				40,133
Exercise of stock options	1,014			$ 1		1,013
Vesting of restricted stock units (in shares)				10,089
Vesting of restricted stock units	0
Stock-based compensation	7,053					7,053
Other comprehensive loss	(14)											(14)
Net loss	(78,249)								(78,249)
Ending balance (in shares) at Mar. 31, 2020				27,548,133
Ending balance at Mar. 31, 2020	(50,246)			$ 28		723,232			(773,515)			9		0
Beginning balance (in shares) at Dec. 31, 2019				27,497,911
Beginning balance at Dec. 31, 2019	$ 19,950			$ 27		715,166			(695,266)			23		0
Increase (Decrease) in Stockholders' Equity
Accounting Standards Update [Extensible List]	espr:AccountingStandardsUpdate202006Member
Ending balance (in shares) at Dec. 31, 2020				25,916,168	25,916,168
Ending balance at Dec. 31, 2020	$ (96,134)	$ (91,927)	$ (188,061)	$ 26	$ 26	797,655	$ (93,475)	$ 704,180	(838,817)	$ 1,548	$ (837,269)	0	$ 0	(54,998)	$ (54,998)
Increase (Decrease) in Stockholders' Equity
Exercise of stock options (in shares)	172,268			172,268
Exercise of stock options	$ 2,668					2,668
Vesting of restricted stock units (in shares)				43,465
Vesting of restricted stock units	0
Vesting of ESPP Shares (in shares)				50,818
Vesting of ESPP Shares	1,183					1,183
Stock-based compensation	5,751					5,751
Net loss	(90,935)								(90,935)
Ending balance (in shares) at Mar. 31, 2021				26,182,719
Ending balance at Mar. 31, 2021	$ (269,394)			$ 26		$ 713,782			$ (928,204)			$ 0		$ (54,998)

Condensed Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
Condensed Statements of Cash Flows - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Operating activities
Net loss	$ (90,935)	$ (78,249)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	153	106
Accretion of premiums and discounts on investments	0	(73)
Amortization of debt issuance costs	400	0
Non-cash interest expense related to the revenue interest liability	4,925	4,171
Stock-based compensation expense	5,751	7,053
Changes in assets and liabilities:
Prepaids and other assets	(9,808)	(2,538)
Deferred revenue	881	(982)
Inventories	(3,894)	(1,841)
Accounts payable	(21,583)	(13,650)
Other accrued liabilities	25,042	16,656
Net cash used in operating activities	(89,068)	(69,347)
Investing activities
Purchases of investments	0	(4,420)
Proceeds from sales/maturities of investments	0	31,200
Purchase of property and equipment	0	(191)
Net cash provided by investing activities	0	26,589
Financing activities
Proceeds from revenue interest liability	0	25,000
Proceeds from exercise of common stock options	2,668	1,014
Payments on revenue interest liability	(573)	0
Payment of debt issuance costs	(50)	0
Net cash provided by financing activities	2,045	26,014
Net decrease in cash and cash equivalents	(87,023)	(16,744)
Cash, cash equivalents and restricted cash at beginning of period	304,962	167,058
Cash, cash equivalents and restricted cash at end of period	217,939	150,314
Supplemental disclosure of cash flow information:
Purchase of property and equipment not yet paid	0	408
Non cash right of use asset	4	91
Debt issuance costs not yet paid	$ 445	$ 0

The Company and Basis of Presentation	3 Months Ended
The Company and Basis of Presentation	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
The Company and Basis of Presentation	The Company and Basis of Presentation Esperion Therapeutics, Inc. ("the Company”) is the Lipid Management Company, a pharmaceutical company singularly focused on developing and commercializing affordable, oral, once-daily, non-statin medicines for the treatment of patients struggling with elevated low density lipoprotein cholesterol ("LDL-C"). The Esperion team of lipid experts are dedicated to lowering bad cholesterol through the discovery, development and commercialization of innovative medicines and their combinations with established medicines. The Company's first two products were approved by the U.S. Food and Drug Administration ("FDA"), European Medicines Agency ("EMA") and Swiss Agency for Therapeutic Products ("Swissmedic") in 2020. Bempedoic acid and the bempedoic acid / ezetimibe combination tablets are oral, once-daily, non-statin, LDL-C lowering medicines for patients with atherosclerotic cardiovascular disease ("ASCVD") or heterozygous familial hypercholesterolemia ("HeFH"). On April 26, 2021, the Company entered into a license and collaboration agreement with Daiichi Sankyo Co. Ltd ("DS"). Pursuant to the agreement, the Company granted DS exclusive development and commercialization rights to bempedoic acid and the bempedoic acid / ezetimibe combination tablet in South Korea, Taiwan, Hong Kong, Thailand, Vietnam, Brazil, Macao, Cambodia and Myanmar (collectively the "DS Territory"). The agreement allows for potential expansion across geographies including Saudi Arabia, Kuwait, Oman, UAE, Qatar, Bahrain, Yemen, and other Latin American countries. DS will be responsible for commercialization in these territories, while Esperion remains responsible for certain development and regulatory activities in South Korea and Taiwan. The Company will receive an upfront cash payment of $30.0 million in May 2021 and is eligible to receive up to an additional $175.0 million in sales milestones. The Company will also receive tiered royalties ranging from 5 percent to 20 percent on net sales in the DS Territory. On April 26, 2021, the Company entered into Amendment No. 2 (the “RIPA Amendment”) to the Revenue Interest Purchase Agreement ("RIPA') with Eiger III SA LLC (“Oberland”), an affiliate of Oberland Capital LLC, as agent for the purchaser parties thereto dated as of June 26, 2019 (as amended by the Amendment No. 1 dated as of November 9, 2020, the “RIPA”). Pursuant to the RIPA Amendment, Oberland Capital waived the original trailing six-month world-wide net sales condition to the third installment payment under the RIPA and released the final $50 million payment payable to the Company under the terms of the RIPA. The Company and Oberland also agreed to amend additional terms of the RIPA, which are discussed further in Note 15 Subsequent Events. The Company's primary activities since incorporation have been conducting research and development activities, including nonclinical, preclinical and clinical testing, performing business and financial planning, recruiting personnel, and raising capital. The Company received approval by the FDA in February 2020 to commercialize NEXLETOL® and NEXLIZET® in the U.S., and accordingly commenced principal operations on March 30, 2020 with the commercialization of NEXLETOL. The Company is subject to risks and uncertainties which include the need to successfully commercialize its products, research, develop, and clinically test therapeutic products; obtain regulatory approvals for its products; expand its management, commercial and scientific staff; and finance its operations with an ultimate goal of achieving profitable operations. The Company has sustained annual operating losses since inception and expects such losses to continue over the foreseeable future. While management believes current cash resources and future cash received from the Company's net product sales, collaboration agreements with Daiichi Sankyo Europe GmbH ("DSE"), Otsuka Pharmaceutical Co., Ltd. ("Otsuka"), and DS entered into on January 2, 2019, April 17, 2020, and April 26, 2021, respectively, and from the RIPA, will fund operations for the foreseeable future, management may continue to fund operations and advance the development of the Company's products and product candidates through a combination of collaborations with third parties, strategic alliances, licensing arrangements, permitted debt financings, permitted royalty-based financings, and permitted private and public equity offerings or through other sources. The impact of COVID-19 and the uncertainty around the global pandemic could further impact the commercial launch of NEXLETOL and NEXLIZET and the Company’s research and development programs and could result in lower cash flows or higher costs that could further impact the Company’s overall operations and cash needs in the future. If adequate funds are not available, the Company may not be able to continue the development of its current products or future product candidates, or to commercialize its current or future product candidates, if approved. Basis of Presentation The accompanying condensed interim financial statements are unaudited and were prepared by the Company in accordance with generally accepted accounting principles in the United States of America (“GAAP”). In the opinion of management, the Company has made all adjustments, which include only normal recurring adjustments necessary for a fair presentation of the Company’s financial position and results of operations for the interim periods presented. Certain prior year amounts have been reclassified to conform with current year presentation. Certain information and disclosures normally included in the annual financial statements prepared in accordance with GAAP, but that is not required for interim reporting purposes, have been condensed or omitted. These condensed interim financial statements should be read in conjunction with the audited financial statements as of and for the year ended December 31, 2020, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020. The results of operations for the interim periods are not necessarily indicative of the results to be expected for a full year, any other interim periods or any future year or period.

Summary of Significant Accounting Policies	3 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Use of Estimates The preparation of financial statements in accordance with generally accepted accounting principles in the United States requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, net revenues, expenses and related disclosures. Actual results could differ from those estimates. Concentration of Risk The Company enters into a limited number of distribution agreements with distributors and specialty pharmacies. The Company's net product sales are with these customers. As of March 31, 2021 and December 31, 2020, eight customers accounted for all of the Company's net trade receivables. Revenue Recognition In accordance with ASC 606, Revenue from Contracts with Customers, the Company recognizes revenue when a customer obtains control of promised goods or services, in an amount that reflects the consideration the Company expects to receive in exchange for the goods or services provided. To determine revenue recognition for arrangements within the scope of ASC 606, the Company performs the following five steps: identify the contracts with a customer; identify the performance obligations in the contract; determine the transaction price; allocate the transaction price to the performance obligations in the contract; and recognize revenue when or as the entity satisfies a performance obligation. At contract inception the Company assesses the goods or services promised within each contract and determines those that are performance obligations and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when or as the performance obligation is satisfied. The Company derives revenue through two primary sources: collaboration revenue and product sales. Collaboration revenue consists of the collaboration payments to the Company for collaboration arrangements outside of the United States for the development, manufacturing and commercialization of the Company's product candidates by the Company's partners and product sales consists of sales of NEXLETOL and NEXLIZET. a.Collaboration Revenue The Company has entered into agreements related to its activities to develop, manufacture, and commercialize its product candidates. The Company earns collaboration revenue in connection with a collaboration agreement to develop and/or commercialize product candidates where the Company deems the collaborator to be the customer. Revenue is recognized when (or as) the Company satisfies performance obligations under the terms of a contract. Depending on the terms of the arrangement, the Company may defer the recognition of all or a portion of the consideration received as the performance obligations are satisfied. The collaboration agreements may require the Company to deliver various rights, services, and/or goods across the entire life cycle of a product or product candidate. In an agreement involving multiple goods or services promised to be transferred to a customer, the Company must assess, at the inception of the contract, whether each promise represents a separate performance obligation (i.e., is "distinct"), or whether such promises should be combined as a single performance obligation. The terms of the agreement typically include consideration to be provided to the Company in the form of non-refundable up-front payments, development milestones, sales milestones, and royalties on sales of products within a respective territory. The Company recognizes regulatory and approval milestones consideration when it is probable that a future reversal is unlikely to occur. For sales based milestones and royalties based on sales of product in a territory, the Company applies the sales-based royalty exception in ASC 606-10-55-65 to all of these milestones and royalties. At the inception of the contract, the transaction price reflects the amount of consideration the Company expects to be entitled to in exchange for transferring promised goods or services to its customer. In the arrangement where the Company satisfies performance obligation(s) during the regulatory phase over time, the Company recognizes collaboration revenue typically using an input method on the basis of regulatory costs incurred relative to the total expected cost which determines the extent of progress toward completion. The Company reviews the estimate of the transaction price and the total expected cost each period and makes revisions to such estimates as necessary. Under contracted supply agreements with collaborators, the Company may manufacture and supply quantities of active pharmaceutical ingredient (“API”) or bulk tablets reasonably required by collaboration partners for the development or sale of licensed products in their respective territory. The Company recognizes revenue when the collaboration partner has obtained control of the API or bulk tablets. The Company records the costs related to the supply agreement in cost of goods sold on the condensed statements of operations and comprehensive income (loss). Under the Company's collaboration agreements, product sales and cost of sales may be recorded by the Company's collaborators as they are deemed to be the principal in the transaction. The Company receives royalties from the commercialization of such products, and records its share of the variable consideration, representing a percentage of net product sales, as collaboration revenue in the period in which such underlying sales occur and costs are incurred by the collaborator. The collaborator will provide the Company with estimates of its royalties for such quarter; these estimates are reconciled to actual results in the subsequent quarter, and the royalty is adjusted accordingly, as necessary. b.Product Sales, Net On February 21, 2020, the Company announced that the FDA approved NEXLETOL as an adjunct to diet and maximally tolerated statin therapy for the treatment of adults with HeFH or established ASCVD who require additional lowering of LDL-C. On February 26, 2020, the Company announced that the FDA approved NEXLIZET as an adjunct to diet and maximally tolerated statin therapy for the treatment of adults with HeFH or established ASCVD who require additional lowering of LDL-C. On March 30, 2020, NEXLETOL was commercially available in the U.S. through prescription and on June 4, 2020, NEXLIZET was commercially available in the U.S. through prescription. Net product sales totaled $6.4 million and $0.9 million for the three months ended March 31, 2021 and 2020, respectively. The Company sells NEXLETOL and NEXLIZET to wholesalers in the U.S and, in accordance with ASC 606, recognizes revenue at the point in time when the customer is deemed to have obtained control of the product. The customer is deemed to have obtained control of the product at the time of physical receipt of the product at the customers’ distribution facilities, or free on board (“FOB”) destination, the terms of which are designated in the contract. Product sales are recorded at the net selling price, which includes estimates of variable consideration for which reserves are established for (a) rebates and chargebacks, (b) co-pay assistance programs, (c) distribution fees, (d) product returns, and (e) other discounts. Where appropriate, these estimates take into consideration a range of possible outcomes which are probability-weighted for relevant factors such as current contractual and statutory requirements, and forecasted customer buying and payment patterns. Overall, these reserves reflect the Company's best estimates of the amount of consideration to which it is entitled based on the terms of the applicable contract. The amount of variable consideration may be constrained and is included in the net sales price only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue recognized will not occur in a future period. Given the early stage of the Company’s commercial operations it has provided constraint of its variable consideration due to its potential consumption trends. Actual amounts of consideration ultimately received may differ from the Company's estimates. If actual results in the future vary from estimates, the Company adjusts these estimates, which would affect net product revenue and earnings in the period such variances become known. Liabilities for co-pay assistance, expected product returns, rebates, and distributor fees are classified as “Other accrued liabilities” in the condensed balance sheets. Discounts, such as prompt pay discounts, and chargebacks are recorded as a reduction to trade accounts receivable, which is included in “Other prepaid and current assets” in the condensed balance sheets. Forms of Variable Consideration Rebates and Chargebacks: The Company estimates reductions to product sales for Public Health Service Institutions, such as Medicaid, Medicare and Veterans' Administration ("VA") programs, as well as certain other qualifying federal and state government programs, and other group purchasing organizations. The Company estimates these reductions based upon the Company's contracts with government agencies and other organizations, statutorily defined discounts and estimated payor mix. These organizations purchase directly from the Company's wholesalers at a discount and the wholesalers charge the Company back the difference between the wholesaler price and the discounted price. The Company's liability for Medicaid rebates consists of estimates for claims that a state will make for a current quarter. The Company's reserve for this discounted pricing is based on expected sales to qualified healthcare providers and the chargebacks that customers have already claimed. Co-pay assistance: Eligible patients who have commercial insurance may receive assistance from the Company to reduce the patient's out of pocket costs. The Company will buy down the difference between the amount of the eligible patient's co-pay when the drug is purchased at the pharmacy at a determined price. Liabilities for co-pay assistance are calculated by actual program participation from third-party administrators. Distribution Fees: The Company has written contracts with its customers that include terms for distribution fees and costs for inventory management. The Company estimates and records distribution fees due to its customers based on gross sales. Product Returns: The Company generally offers a right of return based on the product’s expiration date and certain spoilage and damaged instances. The Company estimates the amount of product sales that may be returned and records the estimate as a reduction of product sales in the period the related product sales is recognized. The Company’s estimates for expected returns are based primarily on an ongoing analysis of sales information and visibility into the inventory remaining in the distribution channel. Discounts: The Company provides product discounts, such as prompt pay discounts, to its customers. The Company estimates cash discounts based on terms in negotiated contracts and the Company’s expectations regarding future payment patterns. Inventories Inventories are stated at the lower of cost or net realizable value and recognized on a first-in, first-out ("FIFO") method. The Company uses standard cost to determine the cost basis for inventory. Inventory is capitalized based on when future economic benefit is expected to be realized. The Company began capitalizing inventory upon receiving FDA approval for NEXLETOL and NEXLIZET on February 21, 2020 and February 26, 2020, respectively. Prior to the FDA approval of NEXLETOL and NEXLIZET, expenses associated with the manufacturing of the Company's products were recorded as research and development expense. The Company analyzes its inventory levels on a periodic basis to determine if any inventory is at risk for expiration prior to sale or has a cost basis that is greater than its estimated future net realizable value. Any adjustments are recognized through cost of goods sold in the period in which they are incurred. Recently Implemented Accounting Pronouncements In August 2020, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 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) (“ASU 2020-06”). This ASU simplifies the accounting for convertible instruments by removing the separation models for convertible debt with cash conversion features and convertible instruments with a beneficial conversion feature, which requires the fair value of the embedded conversion feature of convertible instruments be allocated to equity. Under ASU 2020-06, a convertible debt instrument with those features will generally be reported as a single liability at its amortized cost with no separate accounting for the embedded conversion features in equity. The adoption of this ASU resulted in the reclassification of the portion of the Company's convertible notes from equity to debt, which also reduces reported interest expense and increases reported net income. ASU 2020-06 requires the application of the if-converted method when calculating diluted earnings per share, eliminating the Company’s ability to use the treasury stock method when certain conditions are met. The ASU is effective for annual reporting periods beginning after December 15, 2021, with early adoption permitted no earlier than fiscal years beginning after December 15, 2020. The Company early adopted this standard as of January 1, 2021 which resulted in a net increase in the convertible notes of approximately $92.0 million, an adjustment to accumulated deficit of $1.5 million, and a reduction to additional paid-in capital of $93.5 million. The tax impact of the adoption was not material. There have been no other material changes to the significant accounting policies previously disclosed in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020.

Collaborations with Third Parties	3 Months Ended
Collaborations with Third Parties	Mar. 31, 2021
Collaborations with Third Parties
Collaborations with Third Parties	Collaborations with Third Parties DSE Agreement Terms On January 2, 2019, the Company entered into a license and collaboration agreement with DSE. Pursuant to the agreement, the Company granted DSE exclusive commercialization rights to bempedoic acid and the bempedoic acid / ezetimibe combination tablets in the European Economic Area and Switzerland (“DSE Territory”). DSE will be responsible for commercialization in the DSE Territory. The Company remains responsible for clinical development, regulatory and manufacturing activities for the licensed products globally, including in the DSE Territory. Pursuant to the agreement, the consideration consists of a $150.0 million upfront cash payment as well as $150.0 million cash payment to the Company upon first commercial sales in the DSE Territory. The Company also is responsible to supply DSE with certain manufacturing supply of the API or bulk tablets. The Company is also eligible to receive a substantial additional regulatory milestone payment upon the grant of the marketing authorisation in the European Union for the CV risk reduction label, depending on the range of relative risk reduction in the CLEAR Outcomes study. In addition, the Company is eligible to receive additional sales milestone payments related to total net sales achievements for DSE in the DSE Territory. Finally, the Company will receive tiered fifteen percent (15%) to twenty-five percent (25%) royalties on net DSE Territory sales. The agreement calls for both parties to participate in a Joint Collaboration Committee (the “DSE JCC”). The DSE JCC is comprised of executive management from each company and the Company will lead in all aspects related to development and DSE will lead in all aspects related to commercialization in the DSE Territory. Agreement Terms Amendment On June 18, 2020, the Company entered into an amendment to the license and collaboration agreement with DSE, dated as of January 2, 2019. In June 2020, the Company completed the transfer of the MAAs for NILEMDO® and NUSTENDI®. Pursuant to the terms of the amendment, DSE paid the Company the second $150.0 million milestone based on completion of the NUSTENDI MAA transfer rather than the first product sale in the EU, as previously agreed. Additionally, the Company and DSE have agreed to expand the DSE Territory, or the territory in which DSE has exclusive commercialization rights to NILEMDO and NUSTENDI to include Turkey. DSE's designated affiliate in Turkey will be solely responsible, at its sole cost and expense, for all regulatory matters relating to such products in Turkey, including obtaining regulatory approval for such products in Turkey. Collaboration Revenue The Company considered the guidance under ASC 606 and concluded that the agreement was in the scope of ASC 606. The Company concluded that the upfront payment of $150.0 million should be included in the transaction price and related to the following performance obligations under the agreement: 1) the license to the Company’s intellectual property and 2) the obligation to provide ongoing regulatory and development activities. The Company used the adjusted market assessment approach in determining the standalone selling price of the Company’s intellectual property and the expected cost plus margin approach in determining the standalone selling price of the Company’s obligation to provide ongoing regulatory and development activities. In the three months ended March 31, 2020, the Company recognized $1.0 million related to the on-going performance obligation for the ongoing regulatory efforts related to the MAA in the DSE Territory. In the three months ended March 31, 2021, the Company recognized collaboration revenue of $1.6 million related to both royalty revenue from DSE following their European launch of NILEMDO and NUSTENDI as well as the sales of bulk tablets to DSE pursuant to the supply agreement that was executed with DSE. All remaining future potential milestone amounts were not included in the transaction price, as they were all determined to be fully constrained following the concepts of ASC 606 due to the fact that such amounts hinge on development activities, regulatory approvals and sales-based milestones. Additionally, the Company expects that any consideration related to sales-based milestones will be recognized when the subsequent sales occur. Otsuka Agreement Terms On April 17, 2020, the Company entered into the Otsuka Agreement with Otsuka. Pursuant to the Otsuka Agreement, the Company granted Otsuka exclusive development and commercialization rights to NEXLETOL and NEXLIZET in Japan. Otsuka will be responsible for all development, regulatory, and commercialization activities in Japan. In addition, Otsuka will fund all clinical development costs associated with the program in Japan. Pursuant to the agreement, the consideration consists of a $60.0 million upfront cash payment and the Company will be eligible to receive additional payments of up to $450.0 million if certain regulatory and commercial milestones are achieved by Otsuka. The potential future milestone payments include up to $20.0 million upon first JNDA submissions in the Otsuka Territory, up to $70.0 million upon the first NHI Price Listing for NEXLETOL in the Otsuka Territory, and up to $50.0 million upon the achievement of the primary major adverse cardiovascular events (“MACE”) in the CLEAR Outcomes study and the CV risk reduction rate on the U.S. label, depending on the range of relative risk reduction in the CLEAR Outcomes study. In addition, the Company is eligible to receive additional sales milestone payments up to $310.0 million related to total net sales achievements for Otsuka in Japan. Finally, the Company will receive tiered fifteen percent (15%) to thirty percent (30%) royalties on net sales in Japan. The agreement calls for both parties to participate in a Joint Collaboration Committee (the "Otsuka JCC"). The Otsuka JCC is comprised of executive management from each company and Otsuka will lead in all aspects related to development and commercialization in the Otsuka Territory. Collaboration Revenue The Company considered the guidance under ASC 606 and concluded that the agreement was in the scope of ASC 606. The Company did not have any collaboration revenue from the Otsuka Agreement during the three months ended March 31, 2021 and 2020. All future potential milestone amounts were not included in the transaction price, as they were all determined to be fully constrained following the concepts of ASC 606 due to the fact that such amounts hinge on development activities, regulatory approvals and sales-based milestones. Additionally, the Company expects that any consideration related to royalties and sales-based milestones will be recognized when the subsequent sales occur. The Company has not yet recognized any revenue for milestone payments as the related regulatory and commercial milestones have not yet been achieved. Other Agreements During December 2020, the Company entered into a licensing agreement with Serometrix to in-license a series of early stage compounds known as scaffolds related to its oral, small molecule PCSK9 inhibitor program. PCSK9 is an enzyme responsible for regulating LDL receptors. PCSK9 inhibitors stop LDL receptors from being broken down, increasing the number of LDL receptors present to remove cholesterol from the blood. The agreement allows the Company use of the PCSK9 compounds, which were patented by Serometrix prior to the licensing agreement, to perform further research and development with the goal of developing a small molecule oral PCSK9 inhibitor that can be taken as a tablet. In exchange for these rights, the Company agreed to pay Serometrix an upfront payment, milestone payments and royalties on net sales of licensed products under the agreement. The Company is obligated to make milestone payments to Serometrix upon the achievement of specified development, regulatory and commercialization milestones. The development milestone payments due under the agreement depend on the licensed product being developed. As part of the agreement, the Company made an upfront cash payment of $12.5 million in December 2020, which was recorded to research and development expense, to Serometrix, with payments in future years tied to specific milestones. 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.

Inventories

3 Months Ended

Mar. 31, 2021

Inventory Disclosure [Abstract]

Inventories

Inventories consist of the following (in thousands):


	March 31, 2021		December 31, 2020
Raw materials	$	17,505	$	13,788
Work in process	2,078		2,028
Finished goods	447		320
	$	20,030	$	16,136

Commitments and Contingencies	3 Months Ended
Commitments and Contingencies	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies On January 12, 2016, a purported stockholder of the Company filed a putative class action lawsuit in the United States District Court for the Eastern District of Michigan, against the Company and Tim Mayleben, captioned Kevin L. Dougherty v. Esperion Therapeutics, Inc., et al. (No. 16-cv-10089). The lawsuit alleges that the Company and Mr. Mayleben violated Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 and SEC Rule 10b-5 by allegedly failing to disclose in an August 17, 2015, public statement that the FDA would require a cardiovascular outcomes trial before approving the Company’s lead product candidate. The lawsuit seeks, among other things, compensatory damages in connection with an allegedly inflated stock price between August 18, 2015, and September 28, 2015, as well as attorneys’ fees and costs. On May 20, 2016, an amended complaint was filed in the lawsuit and on July 5, 2016, the Company filed a motion to dismiss the amended complaint. On December 27, 2016, the court granted the Company’s motion to dismiss with prejudice and entered judgment in the Company’s favor. On January 24, 2017, the plaintiffs in this lawsuit filed a motion to alter or amend the judgment. In May 2017, the court denied the plaintiff’s motion to alter or amend the judgment. In May 2017, the court denied the plaintiff’s motion to alter or amend the judgment. On June 19, 2017, the plaintiffs filed a notice of appeal to the Sixth Circuit Court of Appeals and on September 14, 2017, they filed their opening brief in support of the appeal. The appeal was fully briefed on December 7, 2017, and it was argued before the Sixth Circuit on March 15, 2018. On September 27, 2018, the Sixth Circuit issued an opinion in which it reversed the district court’s dismissal and remanded for further proceedings. On October 11, 2018, the Company filed a petition for rehearing en banc and, on October 23, 2018, the Sixth Circuit Court of Appeals directed plaintiffs to respond to that petition. On December 3, 2018, the Sixth Circuit denied the Company’s petition for en banc rehearing, and on December 11, 2018, the case was returned to the federal district court by mandate from the Sixth Circuit. On December 26, 2018, the Company filed an answer to the amended complaint, and on March 28, 2019, the Company filed its amended answer to the amended complaint. On September 15, 2020, the Company filed a motion for summary judgment, and the plaintiffs filed a motion for partial summary judgment, and on October 23, 2020, the parties filed oppositions to both motions for summary judgment. On November 20, 2020, the Company and plaintiffs filed replies in support of their respective motions. On March 12, 2021, the parties agreed to a settlement in principle of the securities class action, and on April 26, 2021, the parties entered into a stipulation of settlement to resolve all legal claims, in which defendants expressly deny that they have committed any act or omission giving rise to any liability under Section 10(b) of the Securities Exchange Act of 1934. Under the terms of the stipulation of settlement, subject to approval by the court, the Company and certain of the Company's insurance carriers will cause a payment of $18.25 million to be made to the plaintiff class. There is no assurance that the settlement will ultimately be approved or that it will become final. If the settlement does not occur and litigation continues, the Company intends to vigorously defend against it. As a result of this settlement agreement, the Company has recorded a litigation settlement liability of $18.25 million as of March 31, 2021 in other accrued liabilities on the condensed balance sheet, a litigation insurance settlement recovery receivable of $5.0 million, which represents the estimated insurance claim proceeds from our insurance carriers as of March 31, 2021, in other prepaid and current assets on the condensed balance sheet, and recorded a loss on settlement of $13.25 million in selling, general, and administrative expenses on the condensed statement of operations. On December 15, 2016, a purported stockholder of the Company filed a derivative lawsuit in the Court of Chancery of the State of Delaware against Tim Mayleben, Roger Newton, Mary McGowan, Nicole Vitullo, Dov Goldstein, Daniel Janney, Antonio Gotto Jr., Mark McGovern, Gilbert Omenn, Scott Braunstein, and Patrick Enright. The Company is named as a nominal defendant. The lawsuit alleges that the defendants breached their fiduciary duties to the Company when they made or approved improper statements on August 17, 2015, regarding the Company’s lead product candidate’s path to FDA approval, and failed to ensure that reliable systems of internal controls were in place at the Company. On February 8, 2019, the Company and defendants filed a motion to dismiss the derivative lawsuit. On April 23, 2019, the plaintiff filed an opposition to the motion to dismiss the derivative lawsuit, and the Company filed a reply brief on May 15, 2019. On November 6, 2019, the court held a hearing on the motion to dismiss. On February 13, 2020, the court granted the motion to dismiss with prejudice and entered judgment in the Company’s favor. On March 16, 2020, the plaintiff filed a notice of appeal to the Supreme Court of Delaware. On June 1, 2020, the plaintiff filed his opening brief on appeal to the Supreme Court of Delaware. On July 1, 2020, the Company and the defendants filed an answering brief, and on July 16, 2020, the plaintiff filed a reply brief. On October 14, 2020, the Supreme Court of Delaware held oral arguments on the appeal. On October 29, 2020, the Supreme Court of Delaware issued an order affirming the judgment of the Court of Chancery. There have been no other material changes to the Company’s contractual obligations and commitments and contingencies outside the ordinary course of business from those previously disclosed in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020 or noted above.

Investments

3 Months Ended

Mar. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Investments

The following table summarizes the Company’s cash equivalents and short-term investments (in thousands):


	March 31, 2021
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Cash equivalents:
Money market funds	$	206,804	$	—	$	—	$	206,804


Total	$	206,804	$	—	$	—	$	206,804


	December 31, 2020
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Cash equivalents:
Money market funds	$	281,783	$	—	$	—	$	281,783






Total	$	281,783	$	—	$	—	$	281,783

During the three months ended March 31, 2021 and 2020, other income, net in the statements of operations includes interest income on investments of less than $0.1 million and $0.4 million, respectively.

There were no unrealized gains or losses on investments reclassified from accumulated other comprehensive income (loss) to other income in the statements of operations during the three months ended March 31, 2021 and 2020.

In the three months ended March 31, 2021 and 2020, there were no allowances for credit losses and all unrealized gains (losses) for available-for-sale securities were recognized in accumulated other comprehensive income (loss). As of March 31, 2021 and December 31, 2020, the Company had no accrued interest receivables.

Fair Value Measurements

3 Months Ended

Mar. 31, 2021

Fair Value Disclosures [Abstract]

Fair Value Measurements

The Company follows accounting guidance that emphasizes that fair value is a market-based measurement, not an entity-specific measurement. Fair value is defined as “the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date.” Fair value measurements are defined on a three level hierarchy:


Level 1 inputs:						Quoted prices for identical assets or liabilities in active markets;

Level 2 inputs:						Observable inputs other than Level 1 prices, such as quoted market prices for similar assets or liabilities or other inputs that are observable or can be corroborated by market data; and

Level 3 inputs:						Unobservable inputs that are supported by little or no market activity and require the reporting entity to develop assumptions that market participants would use when pricing the asset or liability.

The following table presents the Company’s financial assets that have been measured at fair value on a recurring basis (in thousands):


Description	Total		Level 1		Level 2		Level 3

March 31, 2021
Assets:
Money market funds	$	206,804	$	206,804	$	—	$	—


Total assets at fair value	$	206,804	$	206,804	$	—	$	—
December 31, 2020
Assets:
Money market funds	$	281,783	$	281,783	$	—	$	—




Total assets at fair value	$	281,783	$	281,783	$	—	$	—

There were no transfers between Levels 1, 2 or 3 during the three months ended March 31, 2021 and 2020.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Liability Related to the Revenue Interest Purchase Agreement

3 Months Ended

Mar. 31, 2021

On June 26, 2019, the Company entered into a RIPA with Oberland, as agent for purchasers party thereto (the “Purchasers”), and the Purchasers named therein, to obtain financing in respect to the commercialization and further development of bempedoic acid and the bempedoic acid / ezetimibe combination tablets and other working capital needs. Pursuant to the RIPA, the Company received $125.0 million at closing, less certain issuance costs. The Company is also entitled to receive up to approximately $75.0 million in subsequent installments subject to the terms and conditions set forth in the RIPA: (i) $25.0 million upon certain regulatory approval of its product candidates and (ii) $50.0 million, at the Company’s option, upon reaching $100.0 million trailing worldwide six-month net sales any time prior to December 31, 2021 (the “Third Payment”). In March 2020, the Company received $25.0 million from Oberland upon receiving regulatory approval of NEXLETOL.

As consideration for such payments, the Purchasers have a right to receive certain revenue interests (the “Revenue Interests”) from the Company based upon net sales of the Company’s certain products which will be tiered payments initially ranging from 2.5% to 7.5% of the Company’s net sales in the covered territory (the “Covered Territory”); provided that (a) if annual net sales equal or exceed $350.0 million by December 31, 2021 (the “Sales Threshold”), the initially tiered revenue interest rate will be decreased to a single rate of 2.5% of the Company’s net sales in the Covered Territory, beginning on January 1, 2022, and (b) if annual net sales equal or exceed the Sales Threshold and if the Purchasers receive 100% of their invested capital by December 31, 2024, the revenue interest rate will be decreased to a single rate of 0.4% of the Company’s net sales in the Covered Territory beginning on January 1, 2025. If the Third Payment is drawn down by the Company, the applicable royalty rates will increase by one-third. The Covered Territory is the United States, but is subject to expand to include the world-wide net sales if the Company’s annual U.S. net sales are less than $350.0 million for the year ended December 31, 2021. The U.S. net sales milestone thresholds are not to be taken as financial guidance. The Purchasers’ rights to receive the Revenue Interests shall terminate on the date on which the Purchasers have received Revenue Interests payments of 195% of the then aggregate purchase price (the “Cumulative Purchaser Payments”) paid to the Company, unless the RIPA is terminated earlier.

Under the RIPA, the Company has an option (the “Call Option”) to terminate the RIPA and repurchase future Revenue Interests at any time upon advance written notice. Additionally, the Purchasers have an option (the “Put Option”) to terminate the RIPA and to require the Company to repurchase future Revenue Interests upon enumerated events such as a bankruptcy event, an uncured material breach, a material adverse effect or a change of control. If the Put Option is exercised prior to the first anniversary of the closing date by the Purchasers (except pursuant to a change of control), the required repurchase price will be 120% of the Cumulative Purchaser Payments (minus all payments Company has made to the Purchasers in connection with the Revenue Interests). In all other cases, if the Put Option or the Call Option are exercised, the required repurchase price will be 175% of the Cumulative Purchaser Payments (minus all payments Company has made to the Purchasers in connection with the Revenue Interests), if such option is exercised prior to the third anniversary of the closing date, and 195% of the Cumulative Purchaser Payments (minus all payments Company has made to the Purchasers in connection with the Revenue Interests), if such option is exercised thereafter.

In addition, the RIPA contains various representations and warranties, information rights, non-financial covenants, indemnification obligations and other provisions that are customary for a transaction of this nature.

In connection with the arrangement, as of March 31, 2021, the Company has recorded a liability, referred to as the “Revenue interest liability” in the condensed balance sheets, of $181.0 million, net of $0.5 million of capitalized issuance costs in connection with the RIPA. The Company imputes interest expense associated with this liability using the effective interest rate method. The effective interest rate is calculated based on the rate that would enable the debt to be repaid in full over the anticipated life of the arrangement. The interest rate on this liability may vary during the term of the agreement depending on a number of factors, including the level of forecasted net sales. The Company evaluates the interest rate quarterly based on its current net sales forecasts utilizing the prospective method.

A significant increase or decrease in net sales will materially impact the revenue interest liability, interest expense and the time period for repayment. The Company recorded approximately $4.9 million and $4.2 million in interest expense related to this arrangement for the three months ended March 31, 2021 and 2020, respectively.

The repayment of the RIPA to Oberland does not have a fixed repayment schedule, rather it will be completely repaid and extinguished when the Company has repaid 195% of the aggregate purchase price unless the RIPA is terminated earlier. Since there is not a fixed repayment schedule, the Company does not project its future repayments by year. Each period, the Company estimates the future expected sales of its products in the covered territory and determines the effective annual imputed interest rate, which updates and changes the timing of the Company’s payments. Under the terms of the agreement, every $100 million of net sales generated, less than or equal to $250 million in an annual aggregate year, would result in a repayment obligation of approximately $7.5 million or 7.5% at the stated repayment rate in the first year. Annual Net Sales for a calendar year exceeding $250 million would result in a repayment obligation of approximately $2.5 million or 2.5% for every $100 million of sales above the threshold. If the Company equals or exceeds $350 million of sales in the U.S. in 2021, then the repayment amount would drop to $2.5 million for every $100 million of net sales starting in 2022. If the US net sales are less than $350 million for the year ended December 31, 2021, then the Covered Territory is expanded to include worldwide sales beginning in 2022. The Company’s repayments of the RIPA are directly tied to the growth of its net sales, and as the Company’s net sales grow, the Company expects the related repayments of the RIPA to grow as well. The Company currently expects to repay $6.4 million in the next twelve months.

The effective annual imputed interest rate is 11.8% as of March 31, 2021. The Company incurred $0.6 million of issuance costs in connection with the RIPA, which will be amortized to interest expense over the estimated term of the RIPA. Payments made to Oberland as a result of the Company’s net sales will reduce the revenue interest liability.

The following table summarizes the revenue interest liability activity during the three months ended March 31, 2021:


	(in thousands)
Total revenue interest liability at December 31, 2020	$	176,604

Interest expense recognized	4,925
Revenue Interests payments	(573)
Total revenue interest liability at March 31, 2021	$	180,956

Convertible Notes

3 Months Ended

Mar. 31, 2021

Debt Disclosure [Abstract]

Convertible Notes

Convertible NotesOn November 16, 2020, the Company issued $250.0 million aggregate principal amount of 4.0% senior subordinated convertible notes due November 15, 2025. The net proceeds the Company received from the offering of the initial notes was approximately $242.0 million, after deducting the initial purchasers’ discounts and commissions and offering expenses payable by the Company. In connection with the offering of the senior subordinated convertible notes, the Company granted the initial purchasers of the senior subordinated convertible notes a 30-day option to purchase up to an additional $30.0 million aggregate principal amount of the senior subordinated convertible notes on the same terms and conditions. On November 18, 2020 the option was exercised, which resulted in approximately $29.1 million of additional proceeds, for total aggregate principal of $280.0 million and net proceeds of $271.1 million (the additional notes and, together with the initial notes, collectively called the “Convertible Notes”). The Company used approximately $46.0 million of the net proceeds from the offering of the notes to pay the cost of the Capped Call (as defined below) and $55.0 million of the net proceeds from the offering of the initial notes to finance the Prepaid Forward (as defined below). The Convertible Notes are the Company's senior unsecured obligations and mature on November 15, 2025 (the “Maturity Date”), unless earlier repurchased or converted into shares of common stock under certain circumstances described below. The Convertible Notes are convertible into shares of the Company’s common stock, can be repurchased for cash, or a combination thereof, at the Company’s election, at an initial conversion rate of 30.2151 shares of common stock per $1,000 principal amount of the Convertible Notes, which is equivalent to an initial conversion

price of approximately $33.096 per share of common stock, subject to adjustment. The Company will pay interest on the Convertible Notes semi-annually in arrears on May 15 and November 15 of each year.

The Convertible Notes are general unsecured obligations of the Company that are subordinated in right of payment to indebtedness, obligations and other liabilities under the Company’s RIPA, the revenue interests issued pursuant to such agreement, and any refinancing of the foregoing.

Holders may convert their Convertible Notes at their option at any time prior to the close of business on the business day immediately preceding August 15, 2025 in the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on March 31, 2021 (and only during such calendar quarter), if the last reported sale price per share of the Company’s common stock, par value $0.001 per share (“common stock”), is greater than or equal to 130% of the conversion price for each of at least 20 trading days, whether or not consecutive, during the 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter; (2) during the five business days after any five consecutive trading day period (such five consecutive trading day period, the “measurement period”) in which the trading price per $1,000 principal amount of notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price per share of the Company’s common stock and the conversion rate for the notes on each such trading day; (3) if the Company calls such notes for redemption, any such notes that have been called for redemption may be converted at any time prior to the close of business on the second scheduled trading day immediately preceding the redemption date, but only with respect to the notes called for redemption; and (4) upon the occurrence of specified corporate events, as provided in the Indenture.

On or after August 15, 2025, to the close of business on the second scheduled trading day immediately before the maturity date, holders may convert all or any portion of their notes at the applicable conversion rate at any time at the option of the holder regardless of the foregoing conditions.

In addition, following certain corporate events or following issuance of a notice of redemption, the Company will, in certain circumstances, increase the conversion rate for a holder who elects to convert its notes in connection with such a corporate event or to convert its notes called (or deemed called) for redemption during the related redemption period, as the case may be.

The Convertible Notes will be redeemable, in whole or in part, at the Company’s option at any time, and from time to time, on or after November 20, 2023 and before the 41st scheduled trading day immediately before the maturity date, at a cash redemption price equal to 100% of the principal amount of the notes to be redeemed, plus accrued and unpaid interest, if any, but only if the last reported sale price per share of the Company’s common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive), including the trading day immediately preceding the date the Company sends the related redemption notice, during any 30 consecutive trading day period ending on, and including, the trading day immediately preceding the date on which the Company sends such redemption notice. No sinking fund is provided for the notes. If the Company redeems less than all the outstanding notes, at least $125.0 million aggregate principal amount of notes must be outstanding and not subject to redemption as of the relevant redemption notice date.

If the Company undergoes a “fundamental change” (as defined in the Indenture), holders may require the Company to repurchase their notes for cash all or any portion of their notes at a fundamental change repurchase price equal to 100% of the principal amount of the notes to be repurchased, plus accrued and unpaid interest, to, but excluding, the fundamental change repurchase date. The Indenture includes customary terms and covenants, including certain events of default.

The Company incurred approximately $8.9 million of issuance costs related to the issuance of the Convertible Notes, of which, prior to the adoption of ASU 2020-06 on January 1, 2021, $5.8 million and $3.1 million were allocated and recorded to long-term debt and additional paid-in capital, respectively. The $5.8 million of issuance costs recorded as long-term debt on the condensed balance sheet are amortized over the five-year contractual term of the Convertible Notes using the effective interest method.

Prior to the adoption of ASU 2020-06 on January 1, 2021, the $271.1 million of proceeds received from the issuance of the Convertible Notes were allocated between long-term debt (the “liability component”) of $177.6 million and additional paid-in capital (the “equity component”) of $93.5 million. The fair value of the liability component was measured using rates determined for similar debt instruments without a conversion feature. The carrying amount of the equity component, representing the conversion option, was determined by deducting the fair value of the liability component from the aggregate face value of the Convertible Notes and was included in additional paid-in capital in the condensed balance sheet and was not remeasured as long as it did not to meet the conditions for equity classification. The liability component was to be accreted up

to the face value of the Convertible Notes of $280.0 million, which resulted in additional non-cash interest expense being recognized through the Maturity Date.

With the adoption of ASU 2020-06 as of January 1, 2021, the Company reports the convertible debt liability at the aggregate principal amount less unamortized issuance costs. This resulted in the reclassification of the $93.5 million of the Company’s convertible notes recognized at December 31, 2020 from additional paid in capital to the convertible debt liability. The portion of interest expense previously recognized for the accretion of the convertible debt liability and the true-up of the amortization of the issuance costs of $1.5 million was recorded as an adjustment to accumulated deficit.

The following tables summarizes the outstanding principal and debt issuance cost balances as follows (in thousands):


	Convertible note, debt balance	Debt issuance cost	Convertible notes, net
Balance at December 31, 2020	185,100	(5,733)	179,367
Adjustments to net principal due to adoption of ASU 2020-06	94,900	(2,973)	91,927
Balance at January 1, 2021	280,000	(8,706)	271,294
Balance at March 31, 2021	280,000	(8,306)	271,694

The Company recorded $3.2 million of interest expense during the three months ended March 31, 2021, relating to the cash interest on the convertible notes due semi-annually and amortization of the debt issuance costs.

As of March 31, 2021, no Convertible Notes were convertible pursuant to their terms. The estimated fair value of the Convertible Notes was $295.1 million and $283.4 million and as of March 31, 2021 and December 31, 2020, respectively. The estimated fair value of the Convertible Notes was determined through consideration of quoted market prices. As of March 31, 2021 and December 31, 2020, the if-converted value of the Convertible Notes did not exceed the principal value of those notes.

Capped Call Transactions

In connection with the offering of the Convertible Notes, the Company entered into privately-negotiated capped call transactions with one of the initial purchasers of the convertible notes or its affiliate and certain other financial institutions. The Company used approximately $46.0 million of the net proceeds from the offering of the Convertible Notes to pay the cost of the capped call transactions. The capped call transactions are expected generally to reduce potential dilution to the Company’s common stock upon any conversion of the Convertible Notes and/or offset any cash payments the Company is required to make in excess of the principal amount of converted notes, as the case may be, in the event that the market value per share of the Company’s common stock, as measured under the terms of the capped call transactions at the time of exercise, is greater than the strike price of the capped call transactions (which initially corresponds to the initial conversion price of the Convertible Notes, and is subject to certain adjustments), with such reduction and/or offset subject to a cap initially equal to approximately $55.16 (which represents a premium of approximately 100% over the last reported sale price of the Company’s common stock on November 11, 2020), subject to certain adjustments. The capped call transactions are separate transactions, entered into by the Company and are not part of the terms of the Convertible Notes.

Given that the transactions meet certain accounting criteria, the convertible note capped call transactions are recorded in stockholders’ equity, and they are not accounted for as derivatives and are not remeasured each reporting period. As of March 31, 2021 and December 31, 2020, the Company had not purchased any shares under the convertible note capped call transactions.

Prepaid Forward

In connection with the offering of the Convertible Notes, the Company entered into a prepaid forward stock repurchase transaction (“Prepaid Forward”) with a financial institution (“Forward Counterparty”). Pursuant to the Prepaid Forward, the Company used approximately $55.0 million of the net proceeds from the offering of the Convertible Notes to fund the Prepaid Forward. The aggregate number of shares of the Company’s common stock underlying the Prepaid Forward was approximately 1,994,198. The expiration date for the Prepaid Forward is November 15, 2025, although it may be settled earlier in whole or in part. Upon settlement of the Prepaid Forward, at expiration or upon any early settlement, the Forward Counterparty will deliver to the Company the number of shares of common stock underlying the Prepaid Forward or the portion thereof being settled early. The shares purchased under the Prepaid Forward are treated as treasury stock and not outstanding for purposes of the

calculation of basic and diluted earnings per share, but will remain outstanding for corporate law purposes, including for purposes of any future stockholders’ votes, until the Forward Counterparty delivers the shares underlying the Prepaid Forward to the Company. The Company’s Prepaid Forward hedge transaction exposes the Company to credit risk to the extent that its counterparty may be unable to meet the terms of the transaction. The Company mitigates this risk by limiting its counterparty to a major financial institution.

Balance Sheet Disclosures

3 Months Ended

Mar. 31, 2021

Payables and Accruals [Abstract]

Balance Sheet Disclosures

Prepaid and other current assets consist of the following (in thousands):


	March 31, 2021		December 31, 2020
Accounts receivable	$	17,255	$	12,388
Insurance receivable	5,000		—
Prepaid inventory cost	7,603		5,957
Other prepaid and current assets	4,305		5,609
Total prepaid and other current assets	$	34,163	$	23,954

Other accrued liabilities consist of the following (in thousands):


	March 31, 2021		December 31, 2020
Accrued legal settlement	$	18,250	$	—
Accrued compensation	11,243		15,161
Accrued variable consideration	10,082		5,025
Accrued professional fees	4,845		3,183
Accrued interest on convertible notes	4,169		1,369
Accrued other	177		52
Total other accrued liabilities	$	48,766	$	24,790

Stock Compensation

3 Months Ended

Mar. 31, 2021

Share-based Payment Arrangement [Abstract]

Stock Compensation

Employee Stock Purchase Plan

In April 2020, the board of directors approved the Esperion Therapeutics, Inc. 2020 Employee Stock Purchase Plan (the "ESPP") which was approved by the Company's shareholders on May 28, 2020. The ESPP allows eligible employees to authorize payroll deductions of up to 10% of their base salary or wages up to $25,000 annually to be applied toward the purchase of shares of the Company's common stock on the last trading day of the offering period. Participating employees will purchase shares of the Company's common stock at a discount of up to 15% on the lesser of the closing price of the Company's common stock on the NASDAQ Global Select Market (i) on the first trading day of the offering period or (ii) the last day of any offering period. Offering periods under the ESPP will generally be in six months increments, commencing on September 1 and March 1 of each calendar year with the administrator having the right to establish different offering periods. In the three months ended March 31, 2021, the Company recognized $0.3 million of stock compensation expense related to the ESPP. As of March 31, 2021, there have been 50,818 shares issued and 774,182 shares reserved for future issuance under the ESPP.

Stock Options

The following table summarizes the activity relating to the Company’s options to purchase common stock for the three months ended March 31, 2021:


	Number of Options	Weighted-Average Exercise Price Per Share		Weighted-Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
					(in thousands)
Outstanding at December 31, 2020	4,176,518	$	40.24	5.28	$	18,415
Granted	458,000	$	32.12
Forfeited or expired	(431,675)	$	54.06
Exercised	(172,268)	$	15.49
Outstanding at March 31, 2021	4,030,575	$	38.90	5.75	$	19,711

The following table summarizes information about the Company’s stock option plan as of March 31, 2021:


	Number of Options	Weighted-Average Exercise Price Per Share		Weighted-Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
					(in thousands)
Vested and expected to vest at March 31, 2021	4,030,575	$	38.90	5.75	$	19,711
Exercisable at March 31, 2021	3,025,257	$	36.81	4.75	$	19,711

Stock-based compensation related to stock options was $3.7 million and $5.6 million for the three months ended March 31, 2021 and 2020, respectively, including $0.3 million and $0.2 million that were capitalized into inventory. As of March 31, 2021, there was $28.7 million of unrecognized stock-based compensation expense related to unvested options, which will be recognized over a weighted-average period of 2.6 years.

Restricted Stock Units (or RSUs)

The following table summarizes the activity relating to the Company’s RSUs for the three months ended March 31, 2021:


	Number of RSUs	Weighted-Average Fair Value Per Share
Outstanding and unvested December 31, 2020	401,234	$	46.92
Granted	358,280	$	31.75
Forfeited	(76,468)	$	43.09
Vested	(43,465)	$	52.80
Outstanding and unvested March 31, 2021	639,581	$	38.49

Stock-based compensation related to RSUs was approximately $1.8 million and $1.5 million for the three months ended March 31, 2021 and 2020, respectively, including $0.1 million and less than $0.1 million that were capitalized into inventory. As of March 31, 2021, there was $21.8 million of unrecognized stock-based compensation expense related to unvested RSUs, which will be recognized over a weighted-average period of 3.2 years.

Income Taxes	3 Months Ended
Income Taxes	Mar. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income TaxesThere was no provision for income taxes for the three months ended March 31, 2021 and 2020, because the Company has incurred annual operating losses since inception. At March 31, 2021, the Company continues to conclude that it is not more likely than not that the Company will realize the benefit of its deferred tax assets due to its history of losses. Accordingly, a full valuation allowance has been applied against the net deferred tax assets.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References + Details

Net Loss Per Common Share

3 Months Ended

Mar. 31, 2021

Earnings Per Share [Abstract]

Net Loss Per Common Share

Basic net income (loss) per share is calculated by dividing net income (loss) by the weighted-average number of common shares outstanding during the period, without consideration for common stock equivalents. Diluted net income (loss) per share is computed by dividing net income (loss) by the weighted-average number of common stock equivalents outstanding for the period, including shares that potentially could be dilutive if they were exercised or vested during the period, determined using the treasury-stock method. For purposes of this calculation, stock options, unvested RSUs, shares issuable under the ESPP and shares issuable upon conversion of the convertible notes are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive.

The shares outstanding at the end of the respective periods presented below were excluded from the calculation of diluted net loss per share due to their anti-dilutive effect:


	Three Months Ended March 31,
	2021	2020
Common shares under option	4,030,575	4,829,454
Unvested RSUs	639,581	389,762
Shares issuable related to the ESPP	17,838	—
Shares issuable upon conversion of convertible notes	8,460,237	—
Total potential dilutive shares	13,148,231	5,219,216

Statements of Cash Flows

3 Months Ended

Mar. 31, 2021

Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]

Statements of Cash Flows

The following table provides a reconciliation of cash and cash equivalents and restricted cash presented on the condensed balance sheets to the same amounts presented on the condensed statements of cash flows on March 31, 2021 and 2020 and December 31, 2020 and 2019 (in thousands):


	March 31, 2021		March 31, 2020		December 31, 2020		December 31, 2019
Cash and cash equivalents	$	217,939	$	149,386	$	304,962	$	166,130
Restricted cash	—		928		—		928
Total cash and cash equivalents and restricted cash shown on the condensed statements of cash flows	$	217,939	$	150,314	$	304,962	$	167,058

Subsequent events	3 Months Ended
Subsequent events	Mar. 31, 2021
Subsequent Events [Abstract]
Subsequent events	Subsequent events Collaboration Agreement with Daiichi Sankyo Co. Ltd. On April 26, 2021, the Company entered into a license and collaboration agreement (the "DS Agreement") with Daiichi Sankyo Co. Ltd. Pursuant to the agreement, the Company granted DS exclusive development and commercialization rights to bempedoic acid and the bempedoic acid / ezetimibe combination tablet in South Korea, Taiwan, Hong Kong, Thailand, Vietnam, Brazil, Macao, Cambodia and Myanmar (collectively the "DS Territory"). The agreement allows for potential expansion across geographies including Saudi Arabia, Kuwait, Oman, UAE, Qatar, Bahrain, Yemen, and other Latin American countries. DS will be responsible for commercialization in these territories, while Esperion remains responsible for certain development and regulatory activities in South Korea and Taiwan. The Company will receive an upfront cash payment of $30.0 million in May 2021 and is eligible to receive up to an additional $175.0 million in sales milestones. The Company will also receive tiered royalties ranging from 5 percent to 20 percent on net sales in the DS Territory. RIPA Amendment On April 26, 2021, the Company entered into Amendment No. 2 (the “RIPA Amendment”) to the Revenue Interest Purchase Agreement with Eiger III SA LLC (“Oberland”), an affiliate of Oberland Capital LLC, as agent for the purchaser parties thereto dated as of June 26, 2019 (as amended by the Amendment No. 1 dated as of November 9, 2020, the “RIPA”). Pursuant to the RIPA Amendment, Oberland Capital waived the original trailing six-month world-wide net sales condition to the third installment payment under the RIPA and released the final $50 million payment payable to the Company under the terms of the RIPA. The Company and Oberland also agreed to amend additional terms of the RIPA such that the purchasers will have a right to receive certain revenue interests (the “Revenue Interests”) from the Company based on net sales of the Company’s certain products, once approved, which will be tiered payments ranging from 3.33% to 10% (the “Third Payment Applicable Percentage”) of the Company’s net sales in the covered territory (the “Covered Territory”); provided that (a) prior to December 31, 2024, with respect to each country defined in the Daiichi Territory, if the percentage of net sales that Company receives from Daiichi (the “Receivables Percentage”) is less than the Third Payment Applicable Percentage, then the Revenue Interest for such country payable to the purchasers will be equal to the Receivables Percentages, and (b) if annual net sales equal or exceed $350 million and if the Purchasers receive 100% of their invested capital by December 31, 2024, the revenue interest rate will be decreased to a single rate of 3.33% of the Company’s net sales in the Covered Territory for all subsequent calendar quarters. The Covered Territory is the United States, but is subject to expand to include the world-wide net sales if the Company’s annual U.S. net sales are less than $350.0 million for the year ended December 31, 2021. Under the Agreement, the Company has an option (the “Call Option”) to terminate the Agreement and repurchase future Revenue Interests at any time upon advance written notice. Additionally, the Purchasers have an option (the “Put Option”) to terminate the Agreement and to require the Company to repurchase future Revenue Interests upon enumerated events such as a bankruptcy event, an uncured material breach, a material adverse effect or a change of control. If the Put Option or the Call Option are exercised, the required repurchase price will be 200% of the Cumulative Purchaser Payments (minus all payments Company has made to the Purchasers in connection with the Revenue Interests), if such option is exercised prior to the third anniversary of the closing date, and 225% of the Cumulative Purchaser Payments (minus all payments Company has made to the Purchasers in connection with the Revenue Interests), if such option is exercised thereafter.

Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed interim financial statements are unaudited and were prepared by the Company in accordance with generally accepted accounting principles in the United States of America (“GAAP”). In the opinion of management, the Company has made all adjustments, which include only normal recurring adjustments necessary for a fair presentation of the Company’s financial position and results of operations for the interim periods presented. Certain prior year amounts have been reclassified to conform with current year presentation. Certain information and disclosures normally included in the annual financial statements prepared in accordance with GAAP, but that is not required for interim reporting purposes, have been condensed or omitted. These condensed interim financial statements should be read in conjunction with the audited financial statements as of and for the year ended December 31, 2020, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020. The results of operations for the interim periods are not necessarily indicative of the results to be expected for a full year, any other interim periods or any future year or period.
Use of Estimates	Use of Estimates The preparation of financial statements in accordance with generally accepted accounting principles in the United States requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, net revenues, expenses and related disclosures. Actual results could differ from those estimates.
Concentration of Risk	Concentration of Risk The Company enters into a limited number of distribution agreements with distributors and specialty pharmacies. The Company's net product sales are with these customers. As of March 31, 2021 and December 31, 2020, eight customers accounted for all of the Company's net trade receivables.
Revenue Recognition	Revenue Recognition In accordance with ASC 606, Revenue from Contracts with Customers, the Company recognizes revenue when a customer obtains control of promised goods or services, in an amount that reflects the consideration the Company expects to receive in exchange for the goods or services provided. To determine revenue recognition for arrangements within the scope of ASC 606, the Company performs the following five steps: identify the contracts with a customer; identify the performance obligations in the contract; determine the transaction price; allocate the transaction price to the performance obligations in the contract; and recognize revenue when or as the entity satisfies a performance obligation. At contract inception the Company assesses the goods or services promised within each contract and determines those that are performance obligations and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when or as the performance obligation is satisfied. The Company derives revenue through two primary sources: collaboration revenue and product sales. Collaboration revenue consists of the collaboration payments to the Company for collaboration arrangements outside of the United States for the development, manufacturing and commercialization of the Company's product candidates by the Company's partners and product sales consists of sales of NEXLETOL and NEXLIZET. a.Collaboration Revenue The Company has entered into agreements related to its activities to develop, manufacture, and commercialize its product candidates. The Company earns collaboration revenue in connection with a collaboration agreement to develop and/or commercialize product candidates where the Company deems the collaborator to be the customer. Revenue is recognized when (or as) the Company satisfies performance obligations under the terms of a contract. Depending on the terms of the arrangement, the Company may defer the recognition of all or a portion of the consideration received as the performance obligations are satisfied. The collaboration agreements may require the Company to deliver various rights, services, and/or goods across the entire life cycle of a product or product candidate. In an agreement involving multiple goods or services promised to be transferred to a customer, the Company must assess, at the inception of the contract, whether each promise represents a separate performance obligation (i.e., is "distinct"), or whether such promises should be combined as a single performance obligation. The terms of the agreement typically include consideration to be provided to the Company in the form of non-refundable up-front payments, development milestones, sales milestones, and royalties on sales of products within a respective territory. The Company recognizes regulatory and approval milestones consideration when it is probable that a future reversal is unlikely to occur. For sales based milestones and royalties based on sales of product in a territory, the Company applies the sales-based royalty exception in ASC 606-10-55-65 to all of these milestones and royalties. At the inception of the contract, the transaction price reflects the amount of consideration the Company expects to be entitled to in exchange for transferring promised goods or services to its customer. In the arrangement where the Company satisfies performance obligation(s) during the regulatory phase over time, the Company recognizes collaboration revenue typically using an input method on the basis of regulatory costs incurred relative to the total expected cost which determines the extent of progress toward completion. The Company reviews the estimate of the transaction price and the total expected cost each period and makes revisions to such estimates as necessary. Under contracted supply agreements with collaborators, the Company may manufacture and supply quantities of active pharmaceutical ingredient (“API”) or bulk tablets reasonably required by collaboration partners for the development or sale of licensed products in their respective territory. The Company recognizes revenue when the collaboration partner has obtained control of the API or bulk tablets. The Company records the costs related to the supply agreement in cost of goods sold on the condensed statements of operations and comprehensive income (loss). Under the Company's collaboration agreements, product sales and cost of sales may be recorded by the Company's collaborators as they are deemed to be the principal in the transaction. The Company receives royalties from the commercialization of such products, and records its share of the variable consideration, representing a percentage of net product sales, as collaboration revenue in the period in which such underlying sales occur and costs are incurred by the collaborator. The collaborator will provide the Company with estimates of its royalties for such quarter; these estimates are reconciled to actual results in the subsequent quarter, and the royalty is adjusted accordingly, as necessary. b.Product Sales, Net On February 21, 2020, the Company announced that the FDA approved NEXLETOL as an adjunct to diet and maximally tolerated statin therapy for the treatment of adults with HeFH or established ASCVD who require additional lowering of LDL-C. On February 26, 2020, the Company announced that the FDA approved NEXLIZET as an adjunct to diet and maximally tolerated statin therapy for the treatment of adults with HeFH or established ASCVD who require additional lowering of LDL-C. On March 30, 2020, NEXLETOL was commercially available in the U.S. through prescription and on June 4, 2020, NEXLIZET was commercially available in the U.S. through prescription. Net product sales totaled $6.4 million and $0.9 million for the three months ended March 31, 2021 and 2020, respectively. The Company sells NEXLETOL and NEXLIZET to wholesalers in the U.S and, in accordance with ASC 606, recognizes revenue at the point in time when the customer is deemed to have obtained control of the product. The customer is deemed to have obtained control of the product at the time of physical receipt of the product at the customers’ distribution facilities, or free on board (“FOB”) destination, the terms of which are designated in the contract. Product sales are recorded at the net selling price, which includes estimates of variable consideration for which reserves are established for (a) rebates and chargebacks, (b) co-pay assistance programs, (c) distribution fees, (d) product returns, and (e) other discounts. Where appropriate, these estimates take into consideration a range of possible outcomes which are probability-weighted for relevant factors such as current contractual and statutory requirements, and forecasted customer buying and payment patterns. Overall, these reserves reflect the Company's best estimates of the amount of consideration to which it is entitled based on the terms of the applicable contract. The amount of variable consideration may be constrained and is included in the net sales price only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue recognized will not occur in a future period. Given the early stage of the Company’s commercial operations it has provided constraint of its variable consideration due to its potential consumption trends. Actual amounts of consideration ultimately received may differ from the Company's estimates. If actual results in the future vary from estimates, the Company adjusts these estimates, which would affect net product revenue and earnings in the period such variances become known. Liabilities for co-pay assistance, expected product returns, rebates, and distributor fees are classified as “Other accrued liabilities” in the condensed balance sheets. Discounts, such as prompt pay discounts, and chargebacks are recorded as a reduction to trade accounts receivable, which is included in “Other prepaid and current assets” in the condensed balance sheets. Forms of Variable Consideration Rebates and Chargebacks: The Company estimates reductions to product sales for Public Health Service Institutions, such as Medicaid, Medicare and Veterans' Administration ("VA") programs, as well as certain other qualifying federal and state government programs, and other group purchasing organizations. The Company estimates these reductions based upon the Company's contracts with government agencies and other organizations, statutorily defined discounts and estimated payor mix. These organizations purchase directly from the Company's wholesalers at a discount and the wholesalers charge the Company back the difference between the wholesaler price and the discounted price. The Company's liability for Medicaid rebates consists of estimates for claims that a state will make for a current quarter. The Company's reserve for this discounted pricing is based on expected sales to qualified healthcare providers and the chargebacks that customers have already claimed. Co-pay assistance: Eligible patients who have commercial insurance may receive assistance from the Company to reduce the patient's out of pocket costs. The Company will buy down the difference between the amount of the eligible patient's co-pay when the drug is purchased at the pharmacy at a determined price. Liabilities for co-pay assistance are calculated by actual program participation from third-party administrators. Distribution Fees: The Company has written contracts with its customers that include terms for distribution fees and costs for inventory management. The Company estimates and records distribution fees due to its customers based on gross sales. Product Returns: The Company generally offers a right of return based on the product’s expiration date and certain spoilage and damaged instances. The Company estimates the amount of product sales that may be returned and records the estimate as a reduction of product sales in the period the related product sales is recognized. The Company’s estimates for expected returns are based primarily on an ongoing analysis of sales information and visibility into the inventory remaining in the distribution channel. Discounts: The Company provides product discounts, such as prompt pay discounts, to its customers. The Company estimates cash discounts based on terms in negotiated contracts and the Company’s expectations regarding future payment patterns.
Inventories	Inventories Inventories are stated at the lower of cost or net realizable value and recognized on a first-in, first-out ("FIFO") method. The Company uses standard cost to determine the cost basis for inventory. Inventory is capitalized based on when future economic benefit is expected to be realized. The Company began capitalizing inventory upon receiving FDA approval for NEXLETOL and NEXLIZET on February 21, 2020 and February 26, 2020, respectively. Prior to the FDA approval of NEXLETOL and NEXLIZET, expenses associated with the manufacturing of the Company's products were recorded as research and development expense. The Company analyzes its inventory levels on a periodic basis to determine if any inventory is at risk for expiration prior to sale or has a cost basis that is greater than its estimated future net realizable value. Any adjustments are recognized through cost of goods sold in the period in which they are incurred.
Recently Implemented Accounting Pronouncements	Recently Implemented Accounting Pronouncements In August 2020, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 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) (“ASU 2020-06”). This ASU simplifies the accounting for convertible instruments by removing the separation models for convertible debt with cash conversion features and convertible instruments with a beneficial conversion feature, which requires the fair value of the embedded conversion feature of convertible instruments be allocated to equity. Under ASU 2020-06, a convertible debt instrument with those features will generally be reported as a single liability at its amortized cost with no separate accounting for the embedded conversion features in equity. The adoption of this ASU resulted in the reclassification of the portion of the Company's convertible notes from equity to debt, which also reduces reported interest expense and increases reported net income. ASU 2020-06 requires the application of the if-converted method when calculating diluted earnings per share, eliminating the Company’s ability to use the treasury stock method when certain conditions are met. The ASU is effective for annual reporting periods beginning after December 15, 2021, with early adoption permitted no earlier than fiscal years beginning after December 15, 2020. The Company early adopted this standard as of January 1, 2021 which resulted in a net increase in the convertible notes of approximately $92.0 million, an adjustment to accumulated deficit of $1.5 million, and a reduction to additional paid-in capital of $93.5 million. The tax impact of the adoption was not material. There have been no other material changes to the significant accounting policies previously disclosed in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020.

- Definition

Disclosure of inventory accounting policy for inventory classes, including, but not limited to, basis for determining inventory amounts, methods by which amounts are added and removed from inventory classes, loss recognition on impairment of inventories, and situations in which inventories are stated above cost.

+ References + Details

Inventories (Tables)

3 Months Ended

Mar. 31, 2021

Inventory Disclosure [Abstract]

Schedule of Inventories

Inventories consist of the following (in thousands):


	March 31, 2021		December 31, 2020
Raw materials	$	17,505	$	13,788
Work in process	2,078		2,028
Finished goods	447		320
	$	20,030	$	16,136

Investments (Tables)

3 Months Ended

Mar. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Schedule of Company's Cash Equivalents and Short-Term Investments

The following table summarizes the Company’s cash equivalents and short-term investments (in thousands):


	March 31, 2021
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Cash equivalents:
Money market funds	$	206,804	$	—	$	—	$	206,804


Total	$	206,804	$	—	$	—	$	206,804


	December 31, 2020
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Cash equivalents:
Money market funds	$	281,783	$	—	$	—	$	281,783






Total	$	281,783	$	—	$	—	$	281,783

Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2021

Fair Value Disclosures [Abstract]

Schedule of the Company's Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis

The following table presents the Company’s financial assets that have been measured at fair value on a recurring basis (in thousands):


Description	Total		Level 1		Level 2		Level 3

March 31, 2021
Assets:
Money market funds	$	206,804	$	206,804	$	—	$	—


Total assets at fair value	$	206,804	$	206,804	$	—	$	—
December 31, 2020
Assets:
Money market funds	$	281,783	$	281,783	$	—	$	—




Total assets at fair value	$	281,783	$	281,783	$	—	$	—

Liability Related to the Revenue Interest Purchase Agreement (Tables)

3 Months Ended

Mar. 31, 2021

Summary of Revenue Interest Liability Activity During the Period

The following table summarizes the revenue interest liability activity during the three months ended March 31, 2021:


	(in thousands)
Total revenue interest liability at December 31, 2020	$	176,604

Interest expense recognized	4,925
Revenue Interests payments	(573)
Total revenue interest liability at March 31, 2021	$	180,956

Convertible Notes (Tables)

3 Months Ended

Mar. 31, 2021

Debt Disclosure [Abstract]

Summary of Convertible Debt

The following tables summarizes the outstanding principal and debt issuance cost balances as follows (in thousands):


	Convertible note, debt balance	Debt issuance cost	Convertible notes, net
Balance at December 31, 2020	185,100	(5,733)	179,367
Adjustments to net principal due to adoption of ASU 2020-06	94,900	(2,973)	91,927
Balance at January 1, 2021	280,000	(8,706)	271,294
Balance at March 31, 2021	280,000	(8,306)	271,694

Balance Sheet Disclosures (Tables)

3 Months Ended

Mar. 31, 2021

Payables and Accruals [Abstract]

Summary of Prepaid and Other Current Assets

Prepaid and other current assets consist of the following (in thousands):


	March 31, 2021		December 31, 2020
Accounts receivable	$	17,255	$	12,388
Insurance receivable	5,000		—
Prepaid inventory cost	7,603		5,957
Other prepaid and current assets	4,305		5,609
Total prepaid and other current assets	$	34,163	$	23,954

Schedule of Other Accrued Liabilities

Other accrued liabilities consist of the following (in thousands):


	March 31, 2021		December 31, 2020
Accrued legal settlement	$	18,250	$	—
Accrued compensation	11,243		15,161
Accrued variable consideration	10,082		5,025
Accrued professional fees	4,845		3,183
Accrued interest on convertible notes	4,169		1,369
Accrued other	177		52
Total other accrued liabilities	$	48,766	$	24,790

Stock Compensation (Tables)

3 Months Ended

Mar. 31, 2021

Share-based Payment Arrangement [Abstract]

Summary of Activity Relating to the Company's Options to Purchase Common Stock

The following table summarizes the activity relating to the Company’s options to purchase common stock for the three months ended March 31, 2021:


	Number of Options	Weighted-Average Exercise Price Per Share		Weighted-Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
					(in thousands)
Outstanding at December 31, 2020	4,176,518	$	40.24	5.28	$	18,415
Granted	458,000	$	32.12
Forfeited or expired	(431,675)	$	54.06
Exercised	(172,268)	$	15.49
Outstanding at March 31, 2021	4,030,575	$	38.90	5.75	$	19,711

Summary of Information About the Company's Stock Option Plan

The following table summarizes information about the Company’s stock option plan as of March 31, 2021:


	Number of Options	Weighted-Average Exercise Price Per Share		Weighted-Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
					(in thousands)
Vested and expected to vest at March 31, 2021	4,030,575	$	38.90	5.75	$	19,711
Exercisable at March 31, 2021	3,025,257	$	36.81	4.75	$	19,711

Summary of Activity Relating to the Company's RSUs

The following table summarizes the activity relating to the Company’s RSUs for the three months ended March 31, 2021:


	Number of RSUs	Weighted-Average Fair Value Per Share
Outstanding and unvested December 31, 2020	401,234	$	46.92
Granted	358,280	$	31.75
Forfeited	(76,468)	$	43.09
Vested	(43,465)	$	52.80
Outstanding and unvested March 31, 2021	639,581	$	38.49

Net Loss Per Common Share (Tables)

3 Months Ended

Mar. 31, 2021

Earnings Per Share [Abstract]

Schedule of Shares Excluded From Calculation of Diluted Net Loss Per Share

The shares outstanding at the end of the respective periods presented below were excluded from the calculation of diluted net loss per share due to their anti-dilutive effect:


	Three Months Ended March 31,
	2021	2020
Common shares under option	4,030,575	4,829,454
Unvested RSUs	639,581	389,762
Shares issuable related to the ESPP	17,838	—
Shares issuable upon conversion of convertible notes	8,460,237	—
Total potential dilutive shares	13,148,231	5,219,216

Statements of Cash Flows (Tables)

3 Months Ended

Mar. 31, 2021

Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]

Reconciliation of Cash and Cash Equivalents and Restricted Cash


	March 31, 2021		March 31, 2020		December 31, 2020		December 31, 2019
Cash and cash equivalents	$	217,939	$	149,386	$	304,962	$	166,130
Restricted cash	—		928		—		928
Total cash and cash equivalents and restricted cash shown on the condensed statements of cash flows	$	217,939	$	150,314	$	304,962	$	167,058

The Company and Basis of Presentation (Details) - USD ($)		3 Months Ended
	Apr. 26, 2021	Mar. 31, 2021	Mar. 31, 2020
The Company and Basis of Presentation
Proceeds from revenue interest purchase agreement, net of issuance costs		$ 0	$ 25,000,000
License and Collaboration Agreement \| Daiichi Sankyo Co. Ltd \| Subsequent Event
The Company and Basis of Presentation
Upfront cash payment	$ 30,000,000.0
Potential additional future payments	$ 175,000,000.0
License and Collaboration Agreement \| Daiichi Sankyo Co. Ltd \| Minimum \| Subsequent Event
The Company and Basis of Presentation
Percentage of royalties to be received on the net sales	5.00%
License and Collaboration Agreement \| Daiichi Sankyo Co. Ltd \| Maximum \| Subsequent Event
The Company and Basis of Presentation
Percentage of royalties to be received on the net sales	20.00%
RIPA Amendment \| Oberland \| Subsequent Event
The Company and Basis of Presentation
Proceeds from revenue interest purchase agreement, net of issuance costs	$ 50,000,000

Summary of Significant Accounting Policies (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021 USD ($) customer revenue_source	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($) customer	Jan. 01, 2021 USD ($)
Summary of Significant Accounting Policies
Number of revenue sources \| revenue_source	2
Total Revenues	$ 7,978	$ 1,840
Convertible notes, net of issuance costs	271,694		$ 179,367
Accumulated Deficit	928,204		838,817
Additional Paid in Capital	(713,782)		$ (797,655)
Product sales, net
Summary of Significant Accounting Policies
Total Revenues	$ 6,350	$ 858
Cumulative Effect, Period of Adoption, Adjustment
Summary of Significant Accounting Policies
Convertible notes, net of issuance costs				$ 92,000
Accumulated Deficit				1,500
Additional Paid in Capital				$ 93,500
Trade Receivables \| Customer Concentration Risk
Summary of Significant Accounting Policies
Number of major customers \| customer	8		8

Collaborations with Third Parties (Details) - USD ($)			1 Months Ended		3 Months Ended
Collaborations with Third Parties (Details) - USD ($)	Apr. 17, 2020	Jan. 02, 2019	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2021	Mar. 31, 2020
Collaborations with Third Parties
Total revenues					$ 7,978,000	$ 1,840,000
Collaboration revenue
Collaborations with Third Parties
Total revenues					1,628,000	982,000
Daiichi Sankyo Europe GmbH ("DSE") \| Regulatory performance obligations
Collaborations with Third Parties
Upfront payment, revenue recognized						1,000,000.0
Daiichi Sankyo Europe GmbH ("DSE") \| NILEMDO and NUSTENDI, sales of bulk tablets
Collaborations with Third Parties
Total revenues					1,600,000
License and Collaboration Agreement \| Daiichi Sankyo Europe GmbH ("DSE")
Collaborations with Third Parties
Upfront cash payment		$ 150,000,000.0
Cash payment to the Company upon first commercial sales in the DSE Territory		$ 150,000,000.0
License and Collaboration Agreement \| Daiichi Sankyo Europe GmbH ("DSE") \| Minimum
Collaborations with Third Parties
Percentage of royalties to be received on the net sales		15.00%
License and Collaboration Agreement \| Daiichi Sankyo Europe GmbH ("DSE") \| Maximum
Collaborations with Third Parties
Percentage of royalties to be received on the net sales		25.00%
License and Collaboration Agreement \| Serometrix
Collaborations with Third Parties
Upfront cash payment			$ 12,500,000
Amended License and Collaboration Agreement \| Daiichi Sankyo Europe GmbH ("DSE")
Collaborations with Third Parties
Proceeds received upon completion of NUSTENDI MAA transfer				$ 150,000,000.0
Exclusive Development and Commercialization Rights to NEXLETOL and NEXLIZET Tablets \| Otsuka Pharmaceutical Co, Ltd.
Collaborations with Third Parties
Upfront cash payment	$ 60,000,000.0
Potential additional future payments	$ 450,000,000.0
Exclusive Development and Commercialization Rights to NEXLETOL and NEXLIZET Tablets \| Otsuka Pharmaceutical Co, Ltd. \| Minimum
Collaborations with Third Parties
Percentage of royalties to be received on the net sales	15.00%
Exclusive Development and Commercialization Rights to NEXLETOL and NEXLIZET Tablets \| Otsuka Pharmaceutical Co, Ltd. \| Maximum
Collaborations with Third Parties
Percentage of royalties to be received on the net sales	30.00%
Milestone payment, first JNDA submissions	$ 20,000,000.0
Milestone payment, first NHI Price Listing for NEXLETOL in the Otsuka Territory	70,000,000.0
Milestone payment, achievement of the primary MACE in the CLEAR Outcomes study and CV risk reduction rate on the U.S. label	50,000,000.0
Milestone payments related to total net sales achievements	$ 310,000,000.0
Exclusive Development and Commercialization Rights to NEXLETOL and NEXLIZET Tablets \| Otsuka Pharmaceutical Co, Ltd. \| Collaboration revenue
Collaborations with Third Parties
Total revenues					$ 0	$ 0

Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Raw materials	$ 17,505	$ 13,788
Work in process	2,078	2,028
Finished goods	447	320
Total Inventory	$ 20,030	$ 16,136

Commitments and Contingencies (Details) - Pending Litigation $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($)
Loss Contingencies [Line Items]
Payment to plaintiff	$ 18,250
Accrued legal settlement	18,250
Insurance settlement recovery	5,000
Gain (loss) related to litigation settlement	$ (13,250)

Investments - Summary of Cash Equivalents and Short-Term Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Investments
Amortized Cost	$ 206,804	$ 281,783
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	206,804	281,783
Money market funds \| Cash Equivalents
Investments
Amortized Cost	206,804	281,783
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	$ 206,804	$ 281,783

Investments - Narrative (Details) - USD ($)	3 Months Ended
Investments - Narrative (Details) - USD ($)	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Investments
Other income, net	$ 14,000	$ 368,000
Allowance for credit loss	0	0
Accrued interest receivable	0		$ 0
Reclassification out of Accumulated Other Comprehensive Income
Investments
Other income, net	0	0
Other Nonoperating Income (Expense)
Investments
Interest income on investments		$ 400,000
Other Nonoperating Income (Expense) \| Maximum
Investments
Interest income on investments	$ 100,000

Fair Value Measurements (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Fair value measurements
Estimated Fair Value	$ 206,804	$ 281,783
Recurring fair value measurement
Fair value measurements
Estimated Fair Value	206,804	281,783
Recurring fair value measurement \| Money market funds
Fair value measurements
Estimated Fair Value	206,804	281,783
Recurring fair value measurement \| Level 1
Fair value measurements
Estimated Fair Value	206,804	281,783
Recurring fair value measurement \| Level 1 \| Money market funds
Fair value measurements
Estimated Fair Value	206,804	281,783
Recurring fair value measurement \| Level 2
Fair value measurements
Estimated Fair Value	0	0
Recurring fair value measurement \| Level 2 \| Money market funds
Fair value measurements
Estimated Fair Value	0	0
Recurring fair value measurement \| Level 3
Fair value measurements
Estimated Fair Value	0	0
Recurring fair value measurement \| Level 3 \| Money market funds
Fair value measurements
Estimated Fair Value	$ 0	$ 0

Liability Related to the Revenue Interest Purchase Agreement - Narrative (Details) - USD ($)		1 Months Ended		3 Months Ended
	Jun. 26, 2019	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Liability Related to the Revenue Interest Purchase Agreement
Proceeds from revenue interest liability				$ 0	$ 25,000,000
Revenue interest liability				180,956,000		$ 176,604,000
Interest expense				8,125,000	4,171,000
Revenue Interest Purchase Agreement (RIPA)
Liability Related to the Revenue Interest Purchase Agreement
Revenue interest liability				181,000,000.0
Capitalized issuance costs				500,000
Interest expense				4,900,000	$ 4,200,000
Revenue Interest Purchase Agreement (RIPA) \| Oberland
Liability Related to the Revenue Interest Purchase Agreement
Gross proceeds from revenue interest liability	$ 125,000,000.0
Total amount of subsequent installment, subject to RIPA terms and conditions	75,000,000.0
Amount of subsequent installment, subject to regulatory approval	25,000,000.0
Amount of subsequent installment, subject to achievement of sales threshold	50,000,000.0
Milestone amount for worldwide sales to receive the third payment	$ 100,000,000.0
Consecutive number of months sales must be at or above milestone amount	6 months
Proceeds from revenue interest liability		$ 25,000,000.0
Revenue interest rate which will take effect if annual net sales equals or exceeds the sales threshold by December 31, 2021	2.50%
Initial revenue interest rate	7.50%
Minimum amount of annual net sales to qualify for reduced revenue interest rate by December 31, 2021	$ 350,000,000.0
Percentage of invested capital received by December 31, 2024, to qualify for second reduced revenue interest rate	100.00%
Revenue interest rate if annual net sales equal or exceed the Sales Threshold and if the Purchasers receive 100% of their invested capital by December 31, 2024	0.40%
Percentage of increase in royalty rate upon drawdown of third payment	33.33%
Percentage of revenue interests payment on which agreement terminates	195.00%
Percentage of revenue interests payment on which agreement terminates, if prior to the anniversary of the closing date, if put option is exercised	120.00%
Percentage of revenue interests payment on which agreement terminates, prior to the third anniversary of the closing date, if put option is exercised	175.00%
Percentage of revenue interests payment on which agreement terminates, after the third anniversary of the closing date, if put option is exercised	195.00%
Capitalized issuance costs			$ 600,000
Repayment amount expected to pay in next twelve months				$ 6,400,000
Effective annual imputed interest rate (as a percent)				11.80%
Revenue Interest Purchase Agreement (RIPA) \| Oberland \| Net Sales Less Than $250 Million
Liability Related to the Revenue Interest Purchase Agreement
Initial revenue interest rate	7.50%
Minimum amount of annual net sales to qualify for reduced revenue interest rate by December 31, 2021	$ 250,000,000
Hypothetical sales generated amount	100,000,000
Hypothetical repayment obligation	$ 7,500,000
Revenue Interest Purchase Agreement (RIPA) \| Oberland \| Net Sales Greater Than $250 Million But Less Than $350 Million
Liability Related to the Revenue Interest Purchase Agreement
Revenue interest rate which will take effect if annual net sales equals or exceeds the sales threshold by December 31, 2021	2.50%
Minimum amount of annual net sales to qualify for reduced revenue interest rate by December 31, 2021	$ 250,000,000
Hypothetical sales generated amount	100,000,000
Hypothetical repayment obligation	2,500,000
Revenue Interest Purchase Agreement (RIPA) \| Oberland \| Net Sales Greater Than $350 Million
Liability Related to the Revenue Interest Purchase Agreement
Minimum amount of annual net sales to qualify for reduced revenue interest rate by December 31, 2021	350,000,000
Hypothetical sales generated amount	100,000,000
Hypothetical repayment obligation	$ 2,500,000

Liability Related to the Revenue Interest Purchase Agreement - Summary of Revenue Interest Liability (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Liability From Sale Of Future Revenues [Roll Forward]
Revenue interest liability at December 31, 2020	$ 176,604
Revenue Interests payments	(573)	$ 0
Revenue interest liability at March 31, 2021	180,956
Revenue Interest Purchase Agreement (RIPA)
Liability From Sale Of Future Revenues [Roll Forward]
Interest expense recognized	4,925
Revenue interest liability at March 31, 2021	$ 181,000

Convertible Notes (Details)			3 Months Ended	12 Months Ended
Convertible Notes (Details)	Nov. 18, 2020 USD ($)	Nov. 16, 2020 USD ($) day $ / shares shares	Mar. 31, 2021 USD ($) $ / shares	Dec. 31, 2020 USD ($) $ / shares	Jan. 01, 2021 USD ($)
Debt Instrument [Line Items]
Purchase of capped call options associated with convertible notes		$ 46,000,000.0
Prepayment of forward stock repurchase transaction		$ 55,000,000.0
Common stock, par value (in dollars per share) \| $ / shares			$ 0.001	$ 0.001
Additional Paid in Capital			$ (713,782,000)	$ (797,655,000)
Accumulated Deficit			928,204,000	838,817,000
Underlying common stock (in shares) \| shares		1,994,198
Cumulative Effect, Period of Adoption, Adjustment
Debt Instrument [Line Items]
Additional Paid in Capital					$ 93,500,000
Accumulated Deficit					$ 1,500,000
Capped Call \| Common stock
Debt Instrument [Line Items]
Exercise price (in dollars per share) \| $ / shares		$ 55.16
Class of warrant or right, premium percentage		100.00%
Convertible Senior Notes Due 2025 \| Convertible Debt
Debt Instrument [Line Items]
Debt instrument, face amount	$ 280,000,000.0	$ 250,000,000.0
Debt instrument, stated interest rate		4.00%
Proceeds from debt, net of issuance costs	$ 29,100,000	$ 242,000,000.0		271,100,000
Debt instrument, additional principal amount		$ 30,000,000.0
Proceeds from issuance of convertible notes				280,000,000.0
Debt instrument, convertible, conversion ratio		30.2151
Debt instrument, convertible, conversion price (in dollars per share) \| $ / shares		$ 33.096
Debt instrument, redemption price, percentage		100.00%
Debt issuance cost		$ 8,900,000
Debt instrument, term		5 years
Long-term debt		$ 177,600,000
Debt instrument, convertible, carrying amount of equity component		$ 93,500,000
Debt interest expense			3,200,000
Debt fair value			$ 295,100,000	$ 283,400,000
Convertible Senior Notes Due 2025 \| Convertible Debt \| Period One
Debt Instrument [Line Items]
Common stock, par value (in dollars per share) \| $ / shares		$ 0.001
Debt instrument, convertible, threshold percentage of stock price trigger		130.00%
Debt instrument, convertible, threshold trading days \| day		20
Debt instrument, convertible, threshold consecutive trading days \| day		30
Number of business days \| day		5
Number of consecutive trading days \| day		5
Debt instrument, convertible, threshold percentage of last reported sale price		98.00%
Convertible Senior Notes Due 2025 \| Convertible Debt \| Period Two
Debt Instrument [Line Items]
Debt instrument, convertible, threshold percentage of stock price trigger		130.00%
Debt instrument, convertible, threshold trading days \| day		20
Debt instrument, convertible, threshold consecutive trading days \| day		30
Debt instrument, redemption price, percentage		100.00%
Debt instrument, required amount outstanding		$ 125,000,000.0
Convertible Senior Notes Due 2025 \| Convertible Debt \| Long-term Debt
Debt Instrument [Line Items]
Debt issuance cost		5,800,000
Convertible Senior Notes Due 2025 \| Convertible Debt \| Additional Paid-In Capital
Debt Instrument [Line Items]
Debt issuance cost		$ 3,100,000

Convertible Notes - Summary of Convertible Debt (Details) - Convertible Debt - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Convertible note, debt balance	$ 280,000	$ 185,100
Debt issuance cost	(8,306)	(5,733)
Convertible notes, net	$ 271,694	179,367
Cumulative Effect, Period of Adoption, Adjustment
Debt Instrument [Line Items]
Convertible note, debt balance		94,900
Debt issuance cost		(2,973)
Convertible notes, net		91,927
Cumulative Effect, Period of Adoption, Adjusted Balance
Debt Instrument [Line Items]
Convertible note, debt balance		280,000
Debt issuance cost		(8,706)
Convertible notes, net		$ 271,294

Balance Sheet Disclosures - Prepaid and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Accounts receivable	$ 17,255	$ 12,388
Insurance receivable	5,000	0
Prepaid inventory cost	7,603	5,957
Other prepaid and current assets	4,305	5,609
Other prepaid and current assets	$ 34,163	$ 23,954

Balance Sheet Disclosures - Other Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Accrued legal settlement	$ 18,250	$ 0
Accrued compensation	11,243	15,161
Accrued variable consideration	10,082	5,025
Accrued professional fees	4,845	3,183
Accrued interest on convertible notes	4,169	1,369
Accrued other	177	52
Total other accrued liabilities	$ 48,766	$ 24,790

Stock Compensation - Employee Stock Purchase Plan (Details) - Shares issuable related to the ESPP - USD ($)	1 Months Ended	3 Months Ended
	Apr. 30, 2020	Mar. 31, 2021
Employee Stock Purchase Plan
Maximum annual contributions per employee, as a percentage of base salary	10.00%
Amount of maximum annual contributions per employee	$ 25,000
Purchase discount	15.00%
Duration of offering periods	6 months
Stock-based compensation expense		$ 300,000
Shares issued (in shares)		50,818
Shares reserved for future issuance (in shares)		774,182

Stock Compensation - Schedule of Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Number of Options
Outstanding at the beginning of period (in shares)	4,176,518
Granted (in shares)	458,000
Forfeited or expired (in shares)	(431,675)
Exercised (in shares)	(172,268)
Outstanding at the end of the period (in shares)	4,030,575	4,176,518
Vested and expected to vest (in shares)	4,030,575
Exercisable (in shares)	3,025,257
Weighted-Average Exercise Price Per Share
Outstanding at the beginning of period (in dollars per share)	$ 40.24
Granted (in dollars per share)	32.12
Forfeited or expired (in dollars per share)	54.06
Exercised (in dollars per share)	15.49
Outstanding at the end of the period (in dollars per share)	38.90	$ 40.24
Vested and expected to vest (in dollars per share)	38.90
Exercisable (in dollars per share)	$ 36.81
Weighted-Average Remaining Contractual Term (Years)
Outstanding	5 years 9 months	5 years 3 months 10 days
Vested and expected to vest	5 years 9 months
Exercisable	4 years 9 months
Aggregate Intrinsic Value
Outstanding	$ 19,711	$ 18,415
Vested and expected to vest	19,711
Exercisable	$ 19,711

Stock Compensation - Stock Options Additional Information (Details) - Stock Options - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Stock compensation
Stock-based compensation expense	$ 3.7	$ 5.6
Stock-based compensation capitalized into inventory	0.3	$ 0.2
Unrecognized stock-based compensation expense, options	$ 28.7
Weighted-average period over which remaining unrecognized compensation cost will be recognized	2 years 7 months 6 days

Stock Compensation - RSUs (Details) - RSUs	3 Months Ended
Stock Compensation - RSUs (Details) - RSUs	Mar. 31, 2021 $ / shares shares
Number of RSUs
Outstanding and unvested at the beginning of period (in shares) \| shares	401,234
Granted (in shares) \| shares	358,280
Forfeited or expired (in shares) \| shares	(76,468)
Vested (in shares) \| shares	(43,465)
Outstanding and unvested at the ending of period (in shares) \| shares	639,581
Weighted-Average Fair Value Per Share
Outstanding and unvested at the beginning of period (in dollars per share) \| $ / shares	$ 46.92
Granted (in dollars per share) \| $ / shares	31.75
Forfeited or expired (in dollars per share) \| $ / shares	43.09
Vested (in dollars per share) \| $ / shares	52.80
Outstanding and unvested at the at the end of the period (in dollars per share) \| $ / shares	$ 38.49

Stock Compensation - RSUs Additional Information (Details) - RSUs - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Stock compensation
Stock-based compensation expense	$ 1.8	$ 1.5
Stock-based compensation capitalized into inventory	0.1
Unrecognized stock-based compensation expense, RSUs	$ 21.8
Weighted-average period over which remaining unrecognized compensation cost will be recognized	3 years 2 months 12 days
Maximum
Stock compensation
Stock-based compensation capitalized into inventory		$ 0.1

Income Taxes (Details) - USD ($)	3 Months Ended
Income Taxes (Details) - USD ($)	Mar. 31, 2021	Mar. 31, 2020
Provision for income taxes
Provision for income taxes	$ 0	$ 0

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Net Loss Per Common Share (Details) - shares	3 Months Ended
Net Loss Per Common Share (Details) - shares	Mar. 31, 2021	Mar. 31, 2020
Net Income (Loss) Per Common Share
Total potential dilutive shares (in shares)	13,148,231	5,219,216
Common shares under option
Net Income (Loss) Per Common Share
Total potential dilutive shares (in shares)	4,030,575	4,829,454
Unvested RSUs
Net Income (Loss) Per Common Share
Total potential dilutive shares (in shares)	639,581	389,762
Shares issuable related to the ESPP
Net Income (Loss) Per Common Share
Total potential dilutive shares (in shares)	17,838	0
Shares issuable upon conversion of convertible notes
Net Income (Loss) Per Common Share
Total potential dilutive shares (in shares)	8,460,237	0

Statements of Cash Flows (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	$ 217,939	$ 304,962	$ 149,386	$ 166,130
Restricted cash	0	0	928	928
Total cash and cash equivalents and restricted cash shown on the condensed statements of cash flows	$ 217,939	$ 304,962	$ 150,314	$ 167,058

Subsequent events (Details) - USD ($)		3 Months Ended
Subsequent events (Details) - USD ($)	Apr. 26, 2021	Mar. 31, 2021	Mar. 31, 2020
Subsequent Event [Line Items]
Proceeds from revenue interest purchase agreement, net of issuance costs		$ 0	$ 25,000,000
Daiichi Sankyo Co. Ltd \| Subsequent Event \| License and Collaboration Agreement
Subsequent Event [Line Items]
Upfront cash payment	$ 30,000,000.0
Potential additional future payments	$ 175,000,000.0
Daiichi Sankyo Co. Ltd \| Minimum \| Subsequent Event \| License and Collaboration Agreement
Subsequent Event [Line Items]
Percentage of royalties to be received on the net sales	5.00%
Daiichi Sankyo Co. Ltd \| Maximum \| Subsequent Event \| License and Collaboration Agreement
Subsequent Event [Line Items]
Percentage of royalties to be received on the net sales	20.00%
Oberland \| Subsequent Event \| RIPA Amendment
Subsequent Event [Line Items]
Proceeds from revenue interest purchase agreement, net of issuance costs	$ 50,000,000
Revenue interest rate which will take effect if annual net sales equals or exceeds the sales threshold by December 31, 2024	3.33%
Initial revenue interest rate	10.00%
Minimum amount of annual net sales to qualify for reduced revenue interest rate by December 31, 2024, contingent on 100% invested capital received	$ 350,000,000
Percentage of invested capital received by December 31, 2024, to qualify for second reduced revenue interest rate	100.00%
Amount of annual U.S. net sales for the year ended December 31, 2021 to not have the Covered Territory expand from the United States to world-wide net sales	$ 350,000,000.0
Percentage of revenue interests payment on which agreement terminates, prior to the third anniversary of the closing date, if put option is exercised	200.00%
Percentage of revenue interests payment on which agreement terminates, after the third anniversary of the closing date, if put option is exercised	225.00%