Credit Facilities	3 Months Ended
Mar. 31, 2018
Line of Credit Facility [Abstract]
Credit Facilities	Credit Facilities 2.25% Convertible Senior Notes On December 10, 2013, the Company issued $86.3 million in aggregate principal amount of 2.25% Convertible Senior Notes (the “2.25% Senior Notes”). The 2.25% Senior Notes mature on December 15, 2018 unless earlier repurchased by the Company or converted. The Company received net proceeds of approximately $82.6 million from the sale of the 2.25% Senior Notes, after deducting underwriting discounts and commissions and offering expenses payable by the Company. Interest is payable on the 2.25% Senior Notes on June 15 and December 15 of each year, beginning June 15, 2016. The 2.25% Senior Notes are governed by the terms of a base indenture (the “Base Indenture”), as supplemented by the first supplemental indenture relating to the 2.25% Senior Notes (the “First Supplemental Indenture,” and together with the Base Indenture, the “Indenture”), between the Company and Wells Fargo Bank, National Association (the “Trustee”), each of which were entered into on December 10, 2013. The 2.25% Senior Notes are senior unsecured obligations and are: (a) senior in right of payment to the Company’s future indebtedness that is expressly subordinated in right of payment to the 2.25% Senior Notes; (b) equal in right of payment to the Company’s existing and future unsecured indebtedness that is not so subordinated; (c) effectively junior to any of the Company’s secured indebtedness to the extent of the value of the assets securing such indebtedness; and (d) and structurally junior to all existing and future indebtedness (including trade payables) incurred by the Company’s subsidiaries. The Company could not redeem the 2.25% Senior Notes prior to December 15, 2016. On or after December 15, 2016, the Company may redeem for cash all or any portion of the 2.25% Senior Notes, at its option, but only if the closing sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period ending on, and including, the second trading day immediately preceding the date on which the Company provides notice of redemption, exceeds 130% of the conversion price on each applicable trading day. The redemption price will equal 100% of the principal amount of the 2.25% Senior Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date. No sinking fund is provided for the 2.25% Senior Notes. Holders may convert their 2.25% Senior Notes at any time prior to the close of business on the business day immediately preceding September 15, 2018 only under the following circumstances: (i) during any calendar quarter commencing after the calendar quarter ending on March 31, 2014, if the closing sale price of the Company’s common stock, for at least 20 trading days (whether or not consecutive) in the period of 30 consecutive trading days ending on the last trading day of the calendar quarter immediately preceding the calendar quarter in which the conversion occurs, is more than 130% of the conversion price of the 2.25% Senior Notes in effect on each applicable trading day; (ii) during the five consecutive business-day period following any five consecutive trading-day period in which the trading price for the 2.25% Senior Notes for each such trading day was less than 98% of the closing sale price of the Company’s common stock on such date multiplied by the then-current conversion rate; (iii) if the Company calls all or any portion of the notes for redemption, at any time prior to the close of business on the second scheduled trading day prior to the redemption date; or (iv) upon the occurrence of specified corporate events. On or after September 15, 2018 until the close of business on the second scheduled trading day immediately preceding the stated maturity date, holders may surrender their 2.25% Senior Notes for conversion at any time, regardless of the foregoing circumstances. Upon conversion, the Company will, at its election, pay or deliver, as the case may be, cash, shares of the Company’s common stock or a combination of cash and shares of the Company’s common stock. The initial conversion rate of the 2.25% Senior Notes will be 41.6051 shares of the Company’s common stock for each $1,000 principal amount of 2.25% Senior Notes, which represents an initial conversion price of approximately $24.04 per share. Following certain corporate transactions that occur on or prior to the stated maturity date or the Company’s delivery of a notice of redemption, the Company will increase the conversion rate for a holder that elects to convert its 2.25% Senior Notes in connection with such a corporate transaction. If a fundamental change (as defined in the Indenture) occurs prior to the stated maturity date, holders may require the Company to purchase for cash all or any portion of their 2.25% Senior Notes at a fundamental change purchase price equal to 100% of the principal amount of the 2.25% Senior Notes to be purchased, plus accrued and unpaid interest to, but excluding, the fundamental change purchase date. The 2.25% Senior Notes Indenture contains customary terms and covenants and events of default with respect to the 2.25% Senior Notes. If an event of default (as defined in the Indenture) occurs and is continuing, either the Trustee or the holders of at least 25% in aggregate principal amount of the outstanding 2.25% Senior Notes may declare the principal amount of the 2.25% Senior Notes to be due and payable immediately by notice to the Company (with a copy to the Trustee). If an event of default arising out of certain events of bankruptcy, insolvency or reorganization involving the Company or a significant subsidiary (as set forth in the Indenture) occurs with respect to us, the principal amount of the 2.25% Senior Notes and accrued and unpaid interest, if any, will automatically become immediately due and payable. The Company was not required to separate the conversion option in the 2.25% Senior Notes under ASC 815, "Derivatives and Hedging", and has the ability to settle the 2.25% Senior Notes in cash, common stock or a combination of cash and common stock, at its option. In accordance with cash conversion guidance contained in ASC 470-20, "Debt with Conversion and Other Options", the Company accounted for the 2.25% Senior Notes by allocating the issuance proceeds between the liability and the equity component. The equity component is classified in stockholders’ equity and the resulting discount on the liability component is accreted such that interest expense equals the Company’s nonconvertible debt borrowing rate. The separation was performed by first determining the fair value of a similar debt that does not have an associated equity component. That amount was then deducted from the initial proceeds of the 2.25% Senior Notes as a whole to arrive at a residual amount, which was allocated to the conversion feature that is classified as equity. The initial fair value of the indebtedness was $66.9 million resulting in a $19.3 million allocation to the embedded conversion option. The embedded conversion option was recorded in stockholders’ equity and as debt discount, to be subsequently accreted to interest expense over the term of the 2.25% Senior Notes. Underwriting discounts and commissions and offering expenses totaled $3.7 million and were allocated between the liability and the equity component in proportion to the allocation of proceeds and accounted for as debt issuance costs and equity issuance costs, respectively. As a result, $2.9 million attributable to the indebtedness was recorded as deferred financing costs as a reduction of the 2.25% Senior Convertible Notes, to be subsequently amortized as interest expense over the term of the 2.25% Senior Notes, and $0.8 million attributable to the equity component was recorded as a reduction to additional paid-in-capital in stockholders’ equity. On April 3, 2017, the Company entered into the Facility Agreement with Deerfield, pursuant to which Deerfield agreed to loan to the Company up to $120 million, subject to the terms and conditions set forth in the Facility Agreement. The Company used a portion of the proceeds from the Term Loan to repurchase $68 million aggregate principal amount of outstanding 2.25% Senior Notes, plus the accrued but unpaid interest thereon, from the holders thereof in privately negotiated transactions. Refer to the section entitled Deerfield Facility Agreement below for further discussion. The embedded conversion option of the 2.25% Senior Notes, which was originally recorded in additional paid-in capital, was reduced by $2.2 million. Additionally, $3.2 million related to the reduction of outstanding principal related to the 2.25% Senior Notes was charged to loss on debt extinguishment on the Company’s Condensed Consolidated Statements of Operations and Comprehensive Loss. As of March 31, 2018, the Company had outstanding borrowings of $17.6 million, and deferred financing costs of $0.1 million, related to the 2.25% Senior Notes. There are no principal payments due during the term. Annual interest expense on these notes will range from $1.1 million to $1.5 million through maturity. Capped Call Transactions On December 10, 2013, in connection with the pricing of the 2.25% Senior Notes and the exercise in full of their overallotment option by the underwriters, the Company entered into privately-negotiated capped call transactions (the “Capped Call Transactions”) with Bank of America, N.A., an affiliate of Merrill Lynch, Pierce, Fenner & Smith Incorporated. The Capped Call Transactions initial conversion rate and number of options substantially corresponds to each $1,000 principal amount of 2.25% Senior Notes. The Company used approximately $7.4 million of the net proceeds from the 2.25% Senior Notes offering to pay for the cost of the Capped Call Transactions. The Capped Call Transactions are separate transactions entered into by the Company with Bank of America, N.A., are not part of the terms of the 2.25% Senior Notes and will not change the holders’ rights under the 2.25% Senior Notes. The Capped Call Transactions have anti-dilution adjustments substantially similar to those applicable to the 2.25% Senior Notes. The Capped Call Transactions are derivative instruments that are recorded within stockholders’ equity because they meet an exemption from mark-to-market derivative accounting. The Capped Call Transactions are expected generally to reduce the potential dilution and/or offset potential cash payments that the Company is required to make in excess of the principal amount upon conversion of the 2.25% Senior Notes in the event that the market price per share of the Company’s common stock, as measured under the terms of the Capped Call Transactions, is greater than the strike price of the Capped Call Transactions, which initially corresponds to the $24.04 conversion price of the 2.25% Senior Notes. If, however, the market price per share of the Company’s common stock, as measured under the terms of the Capped Call Transactions, exceeds the initial cap price of $29.02, there would nevertheless be dilution and/or there would not be an offset of such potential cash payments, in each case, to the extent that such market price exceeds the cap price of the Capped Call Transactions. The Company will not be required to make any cash payments to Bank of America, N.A. or any of its affiliates upon the exercise of the options that are a part of the Capped Call Transactions, but will be entitled to receive from Bank of America, N.A. (or an affiliate thereof) a number of shares of the Company’s common stock and/or an amount of cash generally based on the amount by which the market price per share of the Company’s common stock, as measured under the terms of the Capped Call Transactions, is greater than the strike price of the Capped Call Transactions during the relevant valuation period under the Capped Call Transactions. However, if the market price of the Company’s common stock, as measured under the terms of the Capped Call Transactions, exceeds the cap price of the Capped Call Transactions during such valuation period under the Capped Call Transactions, the number of shares of common stock and/or the amount of cash the Company expects to receive upon exercise of the Capped Call Transactions will be capped based on the amount by which the cap price exceeds the strike price of the Capped Call Transactions. For any conversions of 2.25% Senior Notes prior to the close of business on the 55th scheduled trading day immediately preceding the stated maturity date of the 2.25% Senior Notes, including without limitation upon an acquisition of the Company or similar business combination, a corresponding portion of the Capped Call Transactions will be terminated. Upon such termination, the portion of the Capped Call Transactions being terminated will be settled at fair value (subject to certain limitations), as determined by Bank of America, N.A., in its capacity as calculation agent under the Capped Call Transactions, which the Company expects to receive from Bank of America, N.A., and no payments will be due Bank of America, N.A. The capped call expires on December 13, 2018. In connection with the Company’s repurchase of approximately $68 million aggregate principal amount of outstanding 2.25% Senior Notes in April 2017, the Company and Bank of America, N.A. unwound the portion of the Capped Call Transactions relating to the repurchased 2.25% Senior Notes. These Capped Call Transactions were originally classified in stockholders’ equity and continued to meet the criteria for classification thereof while outstanding, and therefore were not subsequently measured at fair value. The Company did not pay or receive any compensation related to the unwind of the Capped Call Transactions. Therefore, the Company accounted for the unwind of the Capped Call Transactions by removing these options at their carrying value in additional paid-in capital and recording an offsetting entry to additional paid-in capital. As a result, the Company did not recognize any gain or loss, and the unwind had no net impact on additional paid-in capital. 3.25% Convertible Senior Notes due 2020 On November 2, 2015, the Company issued $125.0 million aggregate principal amount of 3.25% Senior Convertible Notes due 2020 (the “3.25% Senior Notes”). The 3.25% Senior Notes are governed by the Base Indenture, as amended and supplemented by the second supplemental indenture relating to the 3.25% Senior Notes (the “Second Supplemental Indenture,” and together with the Base Indenture, the “3.25% Senior Notes Indenture”), dated as of November 2, 2015, by and between the Company and the Trustee. The 3.25% Senior Notes are senior unsecured obligations and are: senior in right of payment to the Company’s future indebtedness that is expressly subordinated in right of payment to the 3.25% Senior Notes; equal in right of payment to the Company’s existing and future unsecured indebtedness that is not so subordinated, including the 2.25% Senior Notes; effectively junior to any of the Company’s secured indebtedness to the extent of the value of the assets securing such indebtedness; and structurally junior to all existing and future indebtedness (including trade payables) incurred by the Company’s subsidiaries. The 3.25% Senior Notes accrue interest at a rate of 3.25% per year, payable semi-annually in arrears on May 1 and November 1 of each year, commencing May 1, 2016. The 3.25% Senior Notes mature on November 1, 2020, unless earlier purchased, redeemed or converted into shares of common stock in accordance with the terms of the 3.25% Senior Notes Indenture. The Company may not redeem the 3.25% Senior Notes prior to November 1, 2018. On or after November 1, 2018, the Company may redeem for cash all or any portion of the 3.25% Senior Notes, at its option, but only if the closing sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period ending on, and including, the second trading day immediately preceding the date on which the Company provides notice of redemption, exceeds 130% of the conversion price on each applicable trading day. The redemption date can be no sooner than 30 trading days from the date on which notice of redemption is provided to the holders, during which time, up until two trading days prior to the redemption, the holders may elect to convert all or a portion of the 3.25% Senior Notes into shares of the Company’s common stock. The redemption price will equal 100% of the principal amount of the 3.25% Senior Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date. No sinking fund is provided for the 3.25% Senior Notes. The 3.25% Senior Notes are convertible at the option of the holders: (i) in the calendar quarter following any quarter in which, for at least 20 out of the 30 consecutive trading days (whether or not consecutive) ending on the last day of the quarter, the closing price of the Company’s common stock is more than 130% of the then-current conversion price of the 3.25% Senior Notes; (ii) in the five business days following any five day period in which the trading price per $1,000 note was less than 98% of the product of the closing sale price of the Company’s common stock and the current conversion rate; (iii) in the event that the Company has provided notice of redemption, but no later than two trading days prior to Company’s proposed redemption date; or (iv) upon the occurrence of specified corporate events. On or after August 1, 2020 until the close of business on the second scheduled trading day immediately preceding the stated maturity date, holders may surrender their 3.25% Senior Notes for conversion at any time, regardless of the foregoing circumstances. The initial conversion rate of the 3.25% Senior Notes is 89.4314 shares of the Company’s common stock per $1,000 principal amount of the 3.25% Senior Notes, which is equivalent to an initial conversion price of approximately $11.18 per share. The conversion rate is subject to adjustment upon the occurrence of certain specified events. Upon conversion, the Company will at its election pay or deliver, as the case may be, cash, shares of the Company’s common stock or a combination of cash and shares of the Company’s common stock. If a fundamental change (as defined in the 3.25% Senior Notes Indenture) occurs prior to the stated maturity date, holders may require the Company to purchase for cash all or any portion of their 3.25% Senior Notes at a fundamental change purchase price equal to 100% of the principal amount of the 3.25% Senior Notes to be purchased, plus accrued and unpaid interest. The 3.25% Senior Notes Indenture contains customary terms and covenants and events of default with respect to the 3.25% Senior Notes. If an event of default (as defined in the 3.25% Senior Notes Indenture) occurs and is continuing, either the Trustee or the holders of at least 25% in aggregate principal amount of the outstanding 3.25% Senior Notes may declare the principal amount of the 3.25% Senior Notes to be due and payable immediately by notice to the Company (with a copy to the Trustee). If an event of default arising out of certain events of bankruptcy, insolvency or reorganization involving the Company or a significant subsidiary (as set forth in the 3.25% Senior Notes Indenture) occurs with respect to us, the principal amount of the 3.25% Senior Notes and accrued and unpaid interest, if any, will automatically become immediately due and payable. Upon issuance and through December 31, 2015, the Company was not required to separate the conversion option from the 3.25% Senior Notes under ASC 815, "Derivatives and Hedging". However, because the Company has the ability to settle the 3.25% Senior Notes in cash, common stock or a combination of cash and common stock, the Company applied the cash conversion guidance contained in ASC 470-20, "Debt With Conversion and other Options", and accounted for the 3.25% Senior Notes by allocating the issuance proceeds between the liability-classified debt component and a separate equity component attributable to the conversion option. The equity component is classified in stockholders’ equity and the resulting discount on the liability component is accreted such that interest expense equals the Company’s borrowing rate for nonconvertible loan products of similar duration. The separation was performed by first determining the fair value of a similar debt that does not have an associated equity component. That amount was then deducted from the initial proceeds of the 3.25% Senior Notes as a whole to arrive at a residual amount, which was allocated to the conversion feature that is classified as equity. The initial fair value of the indebtedness was $97.8 million resulting in a $27.2 million allocation to the embedded conversion option. The embedded conversion option was recorded in stockholders’ equity and as a debt discount, to be subsequently accreted to interest expense over the term of the 3.25% Senior Notes. Underwriting discounts and commissions and offering expenses totaled $3.7 million and were allocated between the liability and the equity component in proportion to the allocation of proceeds and accounted for as debt issuance costs and equity issuance costs, respectively. As a result, $2.9 million attributable to the indebtedness was recorded as deferred financing costs as a reduction of the 3.25% Senior Convertible Notes, to be subsequently amortized as interest expense over the term of the 3.25% Senior Notes, and $0.8 million attributable to the equity component was recorded as a reduction to additional paid-in-capital in stockholders’ equity. As of March 31, 2018, the Company had outstanding borrowings of $109.4 million, and deferred financing costs of $1.7 million, related to the 3.25% Senior Notes. There are no principal payments due during the term. Annual interest expense on these 3.25% Senior Notes will range from $9.1 million to $10.7 million through maturity. MidCap Credit Facility On July 29, 2016, the Company entered into a credit and security agreement with MidCap Financial Trust ("MidCap"), as agent for the lenders party thereto and as a lender, whereby the Company could borrow up to the lesser of $50.0 million or its applicable borrowing base of asset-based revolving loans (the “MidCap Credit Facility”). All amounts owing under the MidCap Credit Facility accrued interest at a rate equal to the LIBOR Rate plus four and one tenth percent (4.10%). For purposes of the MidCap Credit Facility, LIBOR Rate meant a per annum rate of interest equal to the greater of (a) one half of one percent (0.50%) and (b) the rate determined by MidCap by dividing (i) the Base LIBOR Rate, meaning the base London interbank offer rate for the applicable interest period, by (ii) the sum of one minus the daily average during such interest period of the aggregate maximum reserve requirement then imposed under Regulation D of the Board of Governors of the Federal Reserve System for “Eurocurrency Liabilities” (as defined therein). The MidCap Credit Facility was secured by substantially all of the Company's assets, excluding its intellectual property (“Collateral”), and placed customary limitations on indebtedness, liens, distributions, acquisitions, investments, and other activities of the Company in a manner designed to protect the Collateral. Deferred financing costs directly related to the MidCap Credit Facility such as legal, origination, and professional services fees totaled $0.9 million, which was recorded as deferred financing costs in other assets, to be subsequently amortized as interest expense over the term of the MidCap Credit Facility. The MidCap Credit Facility also contains a lockbox arrangement clause requiring the Company to maintain a lockbox bank account in favor of the MidCap Credit Facility; Company cash receipts remitted to the lockbox bank account are swept on a regular basis to reduce outstanding borrowings related to the MidCap Credit Facility. In conjunction with the Company’s termination of the Company's prior credit facility with Bank of America and concurrent entry into a credit and security agreement with MidCap in July 2016, the Company entered into a corporate credit card agreement whereby the Company is required to maintain a $2.0 million deposit in favor of the credit card issuer. The deposit account related to these credit cards will be presented as restricted cash on the Company’s Condensed Consolidated Balance Sheet. On April 3, 2017, the Company replaced the MidCap Credit Facility with a new revolving line of credit with Deerfield ELGX Revolver, LLC. As a result, the Company wrote off approximately $0.8 million in deferred financing costs and was required to pay a $2.5 million termination fee to Midcap; the foregoing were charged to loss on debt extinguishment on the Company’s Condensed Consolidated Statements of Operations and Comprehensive Loss. Deerfield Facility Agreement On April 3, 2017 (“Agreement Date”), the Company entered into a Facility Agreement (the “Facility Agreement”) with affiliates of Deerfield Management Company, L.P. (collectively, “Deerfield”), pursuant to which Deerfield agreed to loan to the Company up to $120.0 million, subject to the terms and conditions set forth in the Facility Agreement (the “Term Loan”). The Company drew the entire principal amount of the Term Loan on the Agreement Date. The Company agreed to pay Deerfield a yield enhancement fee equal to 2.25% of the principal amount of the funds disbursed on the Agreement Date. The Company also agreed to reimburse Deerfield for all reasonable out-of-pocket expenses incurred by Deerfield in connection with the negotiation and documentation of the Facility Agreement up to a capped amount. Accordingly, deferred financing costs of $5.1 million were recorded on the Company’s Condensed Consolidated Balance Sheet as a direct reduction of the Term Loan, to be subsequently amortized as interest expense over the effective period of the Term Loan. Concurrently with entering into the Facility Agreement, the Company entered into a Guaranty and Security Agreement with Deerfield (the “Security Agreement”), pursuant to which, as security for the repayment of the Company’s obligations under the Facility Agreement, the Company granted to Deerfield a first priority security interest in substantially all of the Company’s assets including intellectual property, with the priority of such security interest being pari passu with the security interest granted pursuant to the Facility Agreement. Any amounts drawn under the Facility Agreement accrue interest at a rate of 6.87% per annum, payable quarterly in arrears beginning on July 1, 2017 and on the first business day of each calendar quarter thereafter and on the Maturity Date, unless repaid earlier. The Company will be required to pay Deerfield on each of April 2, 2021, April 2, 2022 and April 2, 2023 (the “Maturity Date”), an amortization payment equal to $40 million (or, if on the Maturity Date, the remaining outstanding principal amount of the Term Loan). Upon a change of control of the Company, if the acquirer satisfies certain conditions set forth in the Facility Agreement, such acquirer may assume the outstanding principal amount under the Facility Agreement without penalty. If such acquirer does not satisfy the conditions set forth in the Facility Agreement, Deerfield may, at its option, require the Company to repay the outstanding principal balance under the Facility Agreement plus, depending on the timing of the change of control transaction, the Company may be required to pay a make-whole premium and will be required to pay a change of control fee. At any time on or after the fourth anniversary of the Agreement Date, the Company has the right to prepay any amounts owed under the Facility Agreement without premium or penalty, unless such prepayment occurs in connection with a change of control of the Company, in which case the Company must pay Deerfield a change of control fee unless such change of control occurs beyond a certain period after the Maturity Date. At any time prior to the fourth anniversary of the Agreement Date, any prepayment made by the Company will be subject to a make-whole premium and, if such prepayment occurs in connection with a change of control of the Company, a change of control fee. Any amounts drawn under the Facility Agreement may become immediately due and payable upon customary events of default, as defined in the Facility Agreement, or the consummation of certain change of control transactions, as described above. The Facility Agreement contains various representations and warranties, events of default, and affirmative and negative covenants, customary for financings of this type, including reporting requirements, requirements that the Company maintain timely reporting with the SEC and restrictions on the ability of the Company and its subsidiaries to incur additional liens on their assets, incur additional indebtedness and acquire and dispose of assets outside the ordinary course of business. As of March 31, 2018, the Company had outstanding borrowings of $107.2 million, and deferred financing costs of $4.3 million, related to the Term Loan. Annual interest expense on these notes will range from $1.5 million to $12.7 million through maturity. Warrants In connection with the execution of the Facility Agreement, the Company issued to Deerfield warrants to purchase an aggregate of 6,470,000 shares of common stock of the Company at an exercise price of $9.23 per share (the “Deerfield Warrants”). The number of shares of common stock of the Company into which the Warrants are exercisable and the exercise price of the Warrants will be adjusted to reflect any stock splits, recapitalizations or similar adjustments in the number of outstanding shares of common stock of the Company. The Warrants expire on the seventh anniversary of the Agreement Date. Subject to certain exceptions, the Warrants contain limitations such that the Company may not issue shares of common stock of the Company to Deerfield upon the exercise of the Warrants if such issuance would result in Deerfield beneficially owning in excess of 4.985% of the total number of shares of common stock of the Company then issued and outstanding. The holders of the Warrants may exercise the Warrants for cash, on a cashless basis or through a reduction of an amount of principal outstanding under the Term Loan. In connection with certain major transactions, the holders may have the option to convert the Warrants, in whole or in part, into the right to receive the transaction consideration payable upon consummation of such major transaction in respect of a number of shares of common stock of the Company equal to the Black-Scholes value of the Warrants, as defined therein, and in the case of other major transactions, the holders may have the right to exercise the Warrants, in whole or in part, for a number of shares of common stock of the Company equal to the Black-Scholes value of the Warrants. The Company measured the initial fair value of the 6,470,000 shares underlying the Deerfield Warrants at $14.3 million, net of issuance costs of $0.4 million, and recorded the amount in additional paid-in-capital and as a direct reduction of the Term Loan, to be subsequently amortized as interest expense over the effective period of the Term Loan. Registration Rights Agreement In connection with the Term Loan and the issuance of the Warrants, the Company entered into a Registration Rights Agreement with Deerfield (the “Registration Rights Agreement”). Pursuant to the terms of the Registration Rights Agreement, the Company agreed to file a registration statement on Form S-3 (or if Form S-3 is not then available, such other form of registration statement as is then available) with the Commission on or prior to the 30th day following the Agreement Date, to register for resale the shares of common stock of the Company issuable upon the exercise of the Warrants. The aforementioned registration statement was filed on Form S-3 on May 2, 2017. Credit and Security Agreement On the Agreement Date, the Company entered into a Credit and Security Agreement (the “Credit Agreement”) with Deerfield ELGX Revolver, LLC (“Deerfield Revolver”), pursuant to which the Company could borrow up to the lesser of $50 million or its applicable borrowing base from time to time prior to March 31, 2020 (the “Revolver”). Any outstanding principal under the Revolver will accrue interest at a rate equal to 3-month LIBOR (with a 1% floor) plus 4.60%, payable monthly in arrears on the first business day of the immediately succeeding calendar month and on the maturity date. The Company is subject to other fees in addition to interest on the outstanding principal amount under the Revolver, including in connection with an early termination of the Revolver. As described above, the Deerfield Revolver replaced the Company’s $50.0 million asset-based revolving line of credit with MidCap Financial Trust. As a result, the Company recorded $1.2 million in deferred financing costs related to the Deerfield Revolver and presented these costs in other assets, to be subsequently amortized as interest expense over the term of the Deerfield Revolver, on the Company’s Condensed Consolidated Balance Sheets. The Company’s obligations under the Credit Agreement are secured by a first priority security interest in substantially all of the Company’s assets including intellectual property, with the priority of such security interest being pari passu with the security interest granted pursuant to the Term Loan. In conjunction with the Company’s entry into the Credit Agreement, the Company entered into a corporate credit card agreement whereby the Company is required to maintain a $2.0 million deposit in favor of the credit card issuer. The deposit account related to these credit cards will be presented as restricted cash on the Company’s Condensed Consolidated Balance Sheets. As of December 31, 2017, the Company was not in compliance with the required minimum net revenue threshold set forth in the Credit Agreement. On January 5, 2018, the Company delivered a notice of termination to Deerfield for the Deerfield Revolver under the Credit Agreement. The termination of the Deerfield Revolver was effective on January 12, 2018 (the “Termination Date”) and required the Company to pay $1.3 million in termination fees. Additionally, the Company wrote off $1.0 million in unamortized deferred financing costs as of the Termination Date. The total of $2.3 million was charged to loss on debt extinguishment on the Company’s Consolidated Statements of Operations and Comprehensive Loss.

Credit Facilities

2.25% Convertible Senior Notes

On December 10, 2013, the Company issued $86.3 million in aggregate principal amount of 2.25% Convertible Senior Notes (the “2.25% Senior Notes”). The 2.25% Senior Notes mature on December 15, 2018 unless earlier repurchased by the Company or converted. The Company received net proceeds of approximately $82.6 million from the sale of the 2.25% Senior Notes, after deducting underwriting discounts and commissions and offering expenses payable by the Company. Interest is payable on the 2.25% Senior Notes on June 15 and December 15 of each year, beginning June 15, 2016.

The 2.25% Senior Notes are governed by the terms of a base indenture (the “Base Indenture”), as supplemented by the first supplemental indenture relating to the 2.25% Senior Notes (the “First Supplemental Indenture,” and together with the Base Indenture, the “Indenture”), between the Company and Wells Fargo Bank, National Association (the “Trustee”), each of which were entered into on December 10, 2013.

The 2.25% Senior Notes are senior unsecured obligations and are: (a) senior in right of payment to the Company’s future indebtedness that is expressly subordinated in right of payment to the 2.25% Senior Notes; (b) equal in right of payment to the Company’s existing and future unsecured indebtedness that is not so subordinated; (c) effectively junior to any of the Company’s secured indebtedness to the extent of the value of the assets securing such indebtedness; and (d) and structurally junior to all existing and future indebtedness (including trade payables) incurred by the Company’s subsidiaries.

The Company could not redeem the 2.25% Senior Notes prior to December 15, 2016. On or after December 15, 2016, the Company may redeem for cash all or any portion of the 2.25% Senior Notes, at its option, but only if the closing sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period ending on, and including, the second trading day immediately preceding the date on which the Company provides notice of redemption, exceeds 130% of the conversion price on each applicable trading day. The redemption price will equal 100% of the principal amount of the 2.25% Senior Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date. No sinking fund is provided for the 2.25% Senior Notes.

Holders may convert their 2.25% Senior Notes at any time prior to the close of business on the business day immediately preceding September 15, 2018 only under the following circumstances: (i) during any calendar quarter commencing after the calendar quarter ending on March 31, 2014, if the closing sale price of the Company’s common stock, for at least 20 trading days (whether or not consecutive) in the period of 30 consecutive trading days ending on the last trading day of the calendar quarter immediately preceding the calendar quarter in which the conversion occurs, is more than 130% of the conversion price of the 2.25% Senior Notes in effect on each applicable trading day; (ii) during the five consecutive business-day period following any five consecutive trading-day period in which the trading price for the 2.25% Senior Notes for each such trading day was less than 98% of the closing sale price of the Company’s common stock on such date multiplied by the then-current conversion rate; (iii) if the Company calls all or any portion of the notes for redemption, at any time prior to the close of business on the second scheduled trading day prior to the redemption date; or (iv) upon the occurrence of specified corporate events. On or after September 15, 2018 until the close of business on the second scheduled trading day immediately preceding the stated maturity date, holders may surrender their 2.25% Senior Notes for conversion at any time, regardless of the foregoing circumstances.

Upon conversion, the Company will, at its election, pay or deliver, as the case may be, cash, shares of the Company’s common stock or a combination of cash and shares of the Company’s common stock.

The initial conversion rate of the 2.25% Senior Notes will be 41.6051 shares of the Company’s common stock for each $1,000 principal amount of 2.25% Senior Notes, which represents an initial conversion price of approximately $24.04 per share. Following certain corporate transactions that occur on or prior to the stated maturity date or the Company’s delivery of a notice of redemption, the Company will increase the conversion rate for a holder that elects to convert its 2.25% Senior Notes in connection with such a corporate transaction.

If a fundamental change (as defined in the Indenture) occurs prior to the stated maturity date, holders may require the Company to purchase for cash all or any portion of their 2.25% Senior Notes at a fundamental change purchase price equal to 100% of the principal amount of the 2.25% Senior Notes to be purchased, plus accrued and unpaid interest to, but excluding, the fundamental change purchase date.

The 2.25% Senior Notes Indenture contains customary terms and covenants and events of default with respect to the 2.25% Senior Notes. If an event of default (as defined in the Indenture) occurs and is continuing, either the Trustee or the holders of at least 25% in aggregate principal amount of the outstanding 2.25% Senior Notes may declare the principal amount of the 2.25% Senior Notes to be due and payable immediately by notice to the Company (with a copy to the Trustee). If an event of default arising out of certain events of bankruptcy, insolvency or reorganization involving the Company or a significant subsidiary (as set forth in the Indenture) occurs with respect to us, the principal amount of the 2.25% Senior Notes and accrued and unpaid interest, if any, will automatically become immediately due and payable.

The Company was not required to separate the conversion option in the 2.25% Senior Notes under ASC 815, "Derivatives and Hedging", and has the ability to settle the 2.25% Senior Notes in cash, common stock or a combination of cash and common stock, at its option. In accordance with cash conversion guidance contained in ASC 470-20, "Debt with Conversion and Other Options", the Company accounted for the 2.25% Senior Notes by allocating the issuance proceeds between the liability and the equity component. The equity component is classified in stockholders’ equity and the resulting discount on the liability component is accreted such that interest expense equals the Company’s nonconvertible debt borrowing rate. The separation was performed by first determining the fair value of a similar debt that does not have an associated equity component. That amount was then deducted from the initial proceeds of the 2.25% Senior Notes as a whole to arrive at a residual amount, which was allocated to the conversion feature that is classified as equity. The initial fair value of the indebtedness was $66.9 million resulting in a $19.3 million allocation to the embedded conversion option. The embedded conversion option was recorded in stockholders’ equity and as debt discount, to be subsequently accreted to interest expense over the term of the 2.25% Senior Notes. Underwriting discounts and commissions and offering expenses totaled $3.7 million and were allocated between the liability and the equity component in proportion to the allocation of proceeds and accounted for as debt issuance costs and equity issuance costs, respectively. As a result, $2.9 million attributable to the indebtedness was recorded as deferred financing costs as a reduction of the 2.25% Senior Convertible Notes, to be subsequently amortized as interest expense over the term of the 2.25% Senior Notes, and $0.8 million attributable to the equity component was recorded as a reduction to additional paid-in-capital in stockholders’ equity.

On April 3, 2017, the Company entered into the Facility Agreement with Deerfield, pursuant to which Deerfield agreed to loan to the Company up to $120 million, subject to the terms and conditions set forth in the Facility Agreement. The Company used a portion of the proceeds from the Term Loan to repurchase $68 million aggregate principal amount of outstanding 2.25% Senior Notes, plus the accrued but unpaid interest thereon, from the holders thereof in privately negotiated transactions. Refer to the section entitled Deerfield Facility Agreement below for further discussion. The embedded conversion option of the 2.25% Senior Notes, which was originally recorded in additional paid-in capital, was reduced by $2.2 million. Additionally, $3.2 million related to the reduction of outstanding principal related to the 2.25% Senior Notes was charged to loss on debt extinguishment on the Company’s Condensed Consolidated Statements of Operations and Comprehensive Loss.

As of March 31, 2018, the Company had outstanding borrowings of $17.6 million, and deferred financing costs of $0.1 million, related to the 2.25% Senior Notes. There are no principal payments due during the term. Annual interest expense on these notes will range from $1.1 million to $1.5 million through maturity.

Capped Call Transactions

On December 10, 2013, in connection with the pricing of the 2.25% Senior Notes and the exercise in full of their overallotment option by the underwriters, the Company entered into privately-negotiated capped call transactions (the “Capped Call Transactions”) with Bank of America, N.A., an affiliate of Merrill Lynch, Pierce, Fenner & Smith Incorporated. The Capped Call Transactions initial conversion rate and number of options substantially corresponds to each $1,000 principal amount of 2.25% Senior Notes. The Company used approximately $7.4 million of the net proceeds from the 2.25% Senior Notes offering to pay for the cost of the Capped Call Transactions.

The Capped Call Transactions are separate transactions entered into by the Company with Bank of America, N.A., are not part of the terms of the 2.25% Senior Notes and will not change the holders’ rights under the 2.25% Senior Notes. The Capped Call Transactions have anti-dilution adjustments substantially similar to those applicable to the 2.25% Senior Notes. The Capped Call Transactions are derivative instruments that are recorded within stockholders’ equity because they meet an exemption from mark-to-market derivative accounting.

The Capped Call Transactions are expected generally to reduce the potential dilution and/or offset potential cash payments that the Company is required to make in excess of the principal amount upon conversion of the 2.25% Senior Notes in the event that the market price per share of the Company’s common stock, as measured under the terms of the Capped Call Transactions, is greater than the strike price of the Capped Call Transactions, which initially corresponds to the $24.04 conversion price of the 2.25% Senior Notes. If, however, the market price per share of the Company’s common stock, as measured under the terms of the Capped Call Transactions, exceeds the initial cap price of $29.02, there would nevertheless be dilution and/or there would not be an offset of such potential cash payments, in each case, to the extent that such market price exceeds the cap price of the Capped Call Transactions.

The Company will not be required to make any cash payments to Bank of America, N.A. or any of its affiliates upon the exercise of the options that are a part of the Capped Call Transactions, but will be entitled to receive from Bank of America, N.A. (or an affiliate thereof) a number of shares of the Company’s common stock and/or an amount of cash generally based on the amount by which the market price per share of the Company’s common stock, as measured under the terms of the Capped Call Transactions, is greater than the strike price of the Capped Call Transactions during the relevant valuation period under the Capped Call Transactions. However, if the market price of the Company’s common stock, as measured under the terms of the Capped Call Transactions, exceeds the cap price of the Capped Call Transactions during such valuation period under the Capped Call Transactions, the number of shares of common stock and/or the amount of cash the Company expects to receive upon exercise of the Capped Call Transactions will be capped based on the amount by which the cap price exceeds the strike price of the Capped Call Transactions.

For any conversions of 2.25% Senior Notes prior to the close of business on the 55th scheduled trading day immediately preceding the stated maturity date of the 2.25% Senior Notes, including without limitation upon an acquisition of the Company or similar business combination, a corresponding portion of the Capped Call Transactions will be terminated. Upon such termination, the portion of the Capped Call Transactions being terminated will be settled at fair value (subject to certain limitations), as determined by Bank of America, N.A., in its capacity as calculation agent under the Capped Call Transactions, which the Company expects to receive from Bank of America, N.A., and no payments will be due Bank of America, N.A. The capped call expires on December 13, 2018.

In connection with the Company’s repurchase of approximately $68 million aggregate principal amount of outstanding 2.25% Senior Notes in April 2017, the Company and Bank of America, N.A. unwound the portion of the Capped Call Transactions relating to the repurchased 2.25% Senior Notes. These Capped Call Transactions were originally classified in stockholders’ equity and continued to meet the criteria for classification thereof while outstanding, and therefore were not subsequently measured at fair value. The Company did not pay or receive any compensation related to the unwind of the Capped Call Transactions. Therefore, the Company accounted for the unwind of the Capped Call Transactions by removing these options at their carrying value in additional paid-in capital and recording an offsetting entry to additional paid-in capital. As a result, the Company did not recognize any gain or loss, and the unwind had no net impact on additional paid-in capital.

3.25% Convertible Senior Notes due 2020

On November 2, 2015, the Company issued $125.0 million aggregate principal amount of 3.25% Senior Convertible Notes due 2020 (the “3.25% Senior Notes”). The 3.25% Senior Notes are governed by the Base Indenture, as amended and supplemented by the second supplemental indenture relating to the 3.25% Senior Notes (the “Second Supplemental Indenture,” and together with the Base Indenture, the “3.25% Senior Notes Indenture”), dated as of November 2, 2015, by and between the Company and the Trustee.

The 3.25% Senior Notes are senior unsecured obligations and are: senior in right of payment to the Company’s future indebtedness that is expressly subordinated in right of payment to the 3.25% Senior Notes; equal in right of payment to the Company’s existing and future unsecured indebtedness that is not so subordinated, including the 2.25% Senior Notes; effectively junior to any of the Company’s secured indebtedness to the extent of the value of the assets securing such indebtedness; and structurally junior to all existing and future indebtedness (including trade payables) incurred by the Company’s subsidiaries.

The 3.25% Senior Notes accrue interest at a rate of 3.25% per year, payable semi-annually in arrears on May 1 and November 1 of each year, commencing May 1, 2016. The 3.25% Senior Notes mature on November 1, 2020, unless earlier purchased, redeemed or converted into shares of common stock in accordance with the terms of the 3.25% Senior Notes Indenture.

The Company may not redeem the 3.25% Senior Notes prior to November 1, 2018. On or after November 1, 2018, the Company may redeem for cash all or any portion of the 3.25% Senior Notes, at its option, but only if the closing sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period ending on, and including, the second trading day immediately preceding the date on which the Company provides notice of redemption, exceeds 130% of the conversion price on each applicable trading day. The redemption date can be no sooner than 30 trading days from the date on which notice of redemption is provided to the holders, during which time, up until two trading days prior to the redemption, the holders may elect to convert all or a portion of the 3.25% Senior Notes into shares of the Company’s common stock. The redemption price will equal 100% of the principal amount of the 3.25% Senior Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date. No sinking fund is provided for the 3.25% Senior Notes.

The 3.25% Senior Notes are convertible at the option of the holders: (i) in the calendar quarter following any quarter in which, for at least 20 out of the 30 consecutive trading days (whether or not consecutive) ending on the last day of the quarter, the closing price of the Company’s common stock is more than 130% of the then-current conversion price of the 3.25% Senior Notes; (ii) in the five business days following any five day period in which the trading price per $1,000 note was less than 98% of the product of the closing sale price of the Company’s common stock and the current conversion rate; (iii) in the event that the Company has provided notice of redemption, but no later than two trading days prior to Company’s proposed redemption date; or (iv) upon the occurrence of specified corporate events. On or after August 1, 2020 until the close of business on the second scheduled trading day immediately preceding the stated maturity date, holders may surrender their 3.25% Senior Notes for conversion at any time, regardless of the foregoing circumstances.

The initial conversion rate of the 3.25% Senior Notes is 89.4314 shares of the Company’s common stock per $1,000 principal amount of the 3.25% Senior Notes, which is equivalent to an initial conversion price of approximately $11.18 per share. The conversion rate is subject to adjustment upon the occurrence of certain specified events. Upon conversion, the Company will at its election pay or deliver, as the case may be, cash, shares of the Company’s common stock or a combination of cash and shares of the Company’s common stock.

If a fundamental change (as defined in the 3.25% Senior Notes Indenture) occurs prior to the stated maturity date, holders may require the Company to purchase for cash all or any portion of their 3.25% Senior Notes at a fundamental change purchase price equal to 100% of the principal amount of the 3.25% Senior Notes to be purchased, plus accrued and unpaid interest.

The 3.25% Senior Notes Indenture contains customary terms and covenants and events of default with respect to the 3.25% Senior Notes. If an event of default (as defined in the 3.25% Senior Notes Indenture) occurs and is continuing, either the Trustee or the holders of at least 25% in aggregate principal amount of the outstanding 3.25% Senior Notes may declare the principal amount of the 3.25% Senior Notes to be due and payable immediately by notice to the Company (with a copy to the Trustee). If an event of default arising out of certain events of bankruptcy, insolvency or reorganization involving the Company or a significant subsidiary (as set forth in the 3.25% Senior Notes Indenture) occurs with respect to us, the principal amount of the 3.25% Senior Notes and accrued and unpaid interest, if any, will automatically become immediately due and payable.

Upon issuance and through December 31, 2015, the Company was not required to separate the conversion option from the 3.25% Senior Notes under ASC 815, "Derivatives and Hedging". However, because the Company has the ability to settle the 3.25% Senior Notes in cash, common stock or a combination of cash and common stock, the Company applied the cash conversion guidance contained in ASC 470-20, "Debt With Conversion and other Options", and accounted for the 3.25% Senior Notes by allocating the issuance proceeds between the liability-classified debt component and a separate equity component attributable to the conversion option. The equity component is classified in stockholders’ equity and the resulting discount on the liability component is accreted such that interest expense equals the Company’s borrowing rate for nonconvertible loan products of similar duration. The separation was performed by first determining the fair value of a similar debt that does not have an associated equity component. That amount was then deducted from the initial proceeds of the 3.25% Senior Notes as a whole to arrive at a residual amount, which was allocated to the conversion feature that is classified as equity. The initial fair value of the indebtedness was $97.8 million resulting in a $27.2 million allocation to the embedded conversion option. The embedded conversion option was recorded in stockholders’ equity and as a debt discount, to be subsequently accreted to interest expense over the term of the 3.25% Senior Notes. Underwriting discounts and commissions and offering expenses totaled $3.7 million and were allocated between the liability and the equity component in proportion to the allocation of proceeds and accounted for as debt issuance costs and equity issuance costs, respectively. As a result, $2.9 million attributable to the indebtedness was recorded as deferred financing costs as a reduction of the 3.25% Senior Convertible Notes, to be subsequently amortized as interest expense over the term of the 3.25% Senior Notes, and $0.8 million attributable to the equity component was recorded as a reduction to additional paid-in-capital in stockholders’ equity.

As of March 31, 2018, the Company had outstanding borrowings of $109.4 million, and deferred financing costs of $1.7 million, related to the 3.25% Senior Notes. There are no principal payments due during the term. Annual interest expense on these 3.25% Senior Notes will range from $9.1 million to $10.7 million through maturity.

MidCap Credit Facility

On July 29, 2016, the Company entered into a credit and security agreement with MidCap Financial Trust ("MidCap"), as agent for the lenders party thereto and as a lender, whereby the Company could borrow up to the lesser of $50.0 million or its applicable borrowing base of asset-based revolving loans (the “MidCap Credit Facility”). All amounts owing under the MidCap Credit Facility accrued interest at a rate equal to the LIBOR Rate plus four and one tenth percent (4.10%). For purposes of the MidCap Credit Facility, LIBOR Rate meant a per annum rate of interest equal to the greater of (a) one half of one percent (0.50%) and (b) the rate determined by MidCap by dividing (i) the Base LIBOR Rate, meaning the base London interbank offer rate for the applicable interest period, by (ii) the sum of one minus the daily average during such interest period of the aggregate maximum reserve requirement then imposed under Regulation D of the Board of Governors of the Federal Reserve System for “Eurocurrency Liabilities” (as defined therein).

The MidCap Credit Facility was secured by substantially all of the Company's assets, excluding its intellectual property (“Collateral”), and placed customary limitations on indebtedness, liens, distributions, acquisitions, investments, and other activities of the Company in a manner designed to protect the Collateral.

Deferred financing costs directly related to the MidCap Credit Facility such as legal, origination, and professional services fees totaled $0.9 million, which was recorded as deferred financing costs in other assets, to be subsequently amortized as interest expense over the term of the MidCap Credit Facility. The MidCap Credit Facility also contains a lockbox arrangement clause requiring the Company to maintain a lockbox bank account in favor of the MidCap Credit Facility; Company cash receipts remitted to the lockbox bank account are swept on a regular basis to reduce outstanding borrowings related to the MidCap Credit Facility.

In conjunction with the Company’s termination of the Company's prior credit facility with Bank of America and concurrent entry into a credit and security agreement with MidCap in July 2016, the Company entered into a corporate credit card agreement whereby the Company is required to maintain a $2.0 million deposit in favor of the credit card issuer. The deposit account related to these credit cards will be presented as restricted cash on the Company’s Condensed Consolidated Balance Sheet.

On April 3, 2017, the Company replaced the MidCap Credit Facility with a new revolving line of credit with Deerfield ELGX Revolver, LLC. As a result, the Company wrote off approximately $0.8 million in deferred financing costs and was required to pay a $2.5 million termination fee to Midcap; the foregoing were charged to loss on debt extinguishment on the Company’s Condensed Consolidated Statements of Operations and Comprehensive Loss.

Deerfield Facility Agreement

On April 3, 2017 (“Agreement Date”), the Company entered into a Facility Agreement (the “Facility Agreement”) with affiliates of Deerfield Management Company, L.P. (collectively, “Deerfield”), pursuant to which Deerfield agreed to loan to the Company up to $120.0 million, subject to the terms and conditions set forth in the Facility Agreement (the “Term Loan”). The Company drew the entire principal amount of the Term Loan on the Agreement Date. The Company agreed to pay Deerfield a yield enhancement fee equal to 2.25% of the principal amount of the funds disbursed on the Agreement Date. The Company also agreed to reimburse Deerfield for all reasonable out-of-pocket expenses incurred by Deerfield in connection with the negotiation and documentation of the Facility Agreement up to a capped amount. Accordingly, deferred financing costs of $5.1 million were recorded on the Company’s Condensed Consolidated Balance Sheet as a direct reduction of the Term Loan, to be subsequently amortized as interest expense over the effective period of the Term Loan. Concurrently with entering into the Facility Agreement, the Company entered into a Guaranty and Security Agreement with Deerfield (the “Security Agreement”), pursuant to which, as security for the repayment of the Company’s obligations under the Facility Agreement, the Company granted to Deerfield a first priority security interest in substantially all of the Company’s assets including intellectual property, with the priority of such security interest being pari passu with the security interest granted pursuant to the Facility Agreement.

Any amounts drawn under the Facility Agreement accrue interest at a rate of 6.87% per annum, payable quarterly in arrears beginning on July 1, 2017 and on the first business day of each calendar quarter thereafter and on the Maturity Date, unless repaid earlier. The Company will be required to pay Deerfield on each of April 2, 2021, April 2, 2022 and April 2, 2023 (the “Maturity Date”), an amortization payment equal to $40 million (or, if on the Maturity Date, the remaining outstanding principal amount of the Term Loan).

Upon a change of control of the Company, if the acquirer satisfies certain conditions set forth in the Facility Agreement, such acquirer may assume the outstanding principal amount under the Facility Agreement without penalty. If such acquirer does not satisfy the conditions set forth in the Facility Agreement, Deerfield may, at its option, require the Company to repay the outstanding principal balance under the Facility Agreement plus, depending on the timing of the change of control transaction, the Company may be required to pay a make-whole premium and will be required to pay a change of control fee.

At any time on or after the fourth anniversary of the Agreement Date, the Company has the right to prepay any amounts owed under the Facility Agreement without premium or penalty, unless such prepayment occurs in connection with a change of control of the Company, in which case the Company must pay Deerfield a change of control fee unless such change of control occurs beyond a certain period after the Maturity Date. At any time prior to the fourth anniversary of the Agreement Date, any prepayment made by the Company will be subject to a make-whole premium and, if such prepayment occurs in connection with a change of control of the Company, a change of control fee.

Any amounts drawn under the Facility Agreement may become immediately due and payable upon customary events of default, as defined in the Facility Agreement, or the consummation of certain change of control transactions, as described above.

The Facility Agreement contains various representations and warranties, events of default, and affirmative and negative covenants, customary for financings of this type, including reporting requirements, requirements that the Company maintain timely reporting with the SEC and restrictions on the ability of the Company and its subsidiaries to incur additional liens on their assets, incur additional indebtedness and acquire and dispose of assets outside the ordinary course of business.

As of March 31, 2018, the Company had outstanding borrowings of $107.2 million, and deferred financing costs of $4.3 million, related to the Term Loan. Annual interest expense on these notes will range from $1.5 million to $12.7 million through maturity.

Warrants

In connection with the execution of the Facility Agreement, the Company issued to Deerfield warrants to purchase an aggregate of 6,470,000 shares of common stock of the Company at an exercise price of $9.23 per share (the “Deerfield Warrants”). The number of shares of common stock of the Company into which the Warrants are exercisable and the exercise price of the Warrants will be adjusted to reflect any stock splits, recapitalizations or similar adjustments in the number of outstanding shares of common stock of the Company.

The Warrants expire on the seventh anniversary of the Agreement Date. Subject to certain exceptions, the Warrants contain limitations such that the Company may not issue shares of common stock of the Company to Deerfield upon the exercise of the Warrants if such issuance would result in Deerfield beneficially owning in excess of 4.985% of the total number of shares of common stock of the Company then issued and outstanding.

The holders of the Warrants may exercise the Warrants for cash, on a cashless basis or through a reduction of an amount of principal outstanding under the Term Loan. In connection with certain major transactions, the holders may have the option to convert the Warrants, in whole or in part, into the right to receive the transaction consideration payable upon consummation of such major transaction in respect of a number of shares of common stock of the Company equal to the Black-Scholes value of the Warrants, as defined therein, and in the case of other major transactions, the holders may have the right to exercise the Warrants, in whole or in part, for a number of shares of common stock of the Company equal to the Black-Scholes value of the Warrants.

The Company measured the initial fair value of the 6,470,000 shares underlying the Deerfield Warrants at $14.3 million, net of issuance costs of $0.4 million, and recorded the amount in additional paid-in-capital and as a direct reduction of the Term Loan, to be subsequently amortized as interest expense over the effective period of the Term Loan.

Registration Rights Agreement

In connection with the Term Loan and the issuance of the Warrants, the Company entered into a Registration Rights Agreement with Deerfield (the “Registration Rights Agreement”). Pursuant to the terms of the Registration Rights Agreement, the Company agreed to file a registration statement on Form S-3 (or if Form S-3 is not then available, such other form of registration statement as is then available) with the Commission on or prior to the 30th day following the Agreement Date, to register for resale the shares of common stock of the Company issuable upon the exercise of the Warrants. The aforementioned registration statement was filed on Form S-3 on May 2, 2017.

Credit and Security Agreement

On the Agreement Date, the Company entered into a Credit and Security Agreement (the “Credit Agreement”) with Deerfield ELGX Revolver, LLC (“Deerfield Revolver”), pursuant to which the Company could borrow up to the lesser of $50 million or its applicable borrowing base from time to time prior to March 31, 2020 (the “Revolver”). Any outstanding principal under the Revolver will accrue interest at a rate equal to 3-month LIBOR (with a 1% floor) plus 4.60%, payable monthly in arrears on the first business day of the immediately succeeding calendar month and on the maturity date. The Company is subject to other fees in addition to interest on the outstanding principal amount under the Revolver, including in connection with an early termination of the Revolver.

As described above, the Deerfield Revolver replaced the Company’s $50.0 million asset-based revolving line of credit with MidCap Financial Trust. As a result, the Company recorded $1.2 million in deferred financing costs related to the Deerfield Revolver and presented these costs in other assets, to be subsequently amortized as interest expense over the term of the Deerfield Revolver, on the Company’s Condensed Consolidated Balance Sheets. The Company’s obligations under the Credit Agreement are secured by a first priority security interest in substantially all of the Company’s assets including intellectual property, with the priority of such security interest being pari passu with the security interest granted pursuant to the Term Loan.

In conjunction with the Company’s entry into the Credit Agreement, the Company entered into a corporate credit card agreement whereby the Company is required to maintain a $2.0 million deposit in favor of the credit card issuer. The deposit account related to these credit cards will be presented as restricted cash on the Company’s Condensed Consolidated Balance Sheets.

As of December 31, 2017, the Company was not in compliance with the required minimum net revenue threshold set forth in the Credit Agreement. On January 5, 2018, the Company delivered a notice of termination to Deerfield for the Deerfield Revolver under the Credit Agreement. The termination of the Deerfield Revolver was effective on January 12, 2018 (the “Termination Date”) and required the Company to pay $1.3 million in termination fees. Additionally, the Company wrote off $1.0 million in unamortized deferred financing costs as of the Termination Date. The total of $2.3 million was charged to loss on debt extinguishment on the Company’s Consolidated Statements of Operations and Comprehensive Loss.