21,425,000 Units Each Unit Consisting of One Share of Common Stock ($0.0001 par value per Share) And A Warrant to Purchase 0.50 of a Share of Common Stock HORIZON PHARMA, INC. UNDERWRITING AGREEMENT

Exhibit 1.1

EXECUTION COPY

21,425,000 Units

Each Unit Consisting of

One Share of Common Stock ($0.0001 par value per Share)

And

A Warrant to Purchase 0.50 of a Share of Common Stock

HORIZON PHARMA, INC.

UNDERWRITING AGREEMENT

September 20, 2012

▇▇▇▇▇ and Company, LLC

▇▇▇ ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇

▇▇▇ ▇▇▇▇, ▇▇ ▇▇▇▇▇

JMP Securities LLC

▇▇▇ ▇▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇▇▇ ▇▇▇▇

▇▇▇ ▇▇▇▇▇▇▇▇▇, ▇▇ ▇▇▇▇▇

▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated

▇▇▇ ▇▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇▇▇ ▇▇▇▇

▇▇▇ ▇▇▇▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇

As Representatives of the several Underwriters

Ladies and Gentlemen:

Introductory. Horizon Pharma, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 21,425,000 units (the “Units”), each of which shall consist of (i) one (1) share of the Company’s common stock, par value $0.0001 per share (the “Common Stock”) (such shares of Common Stock constituting a part of the Units, collectively the “Shares”), and (ii) a warrant of the Company in the form set forth in Exhibit C hereto, to purchase 0.50 of a share of Common Stock (such warrants constituting a part of the Units, collectively the “Warrants”). The shares of Common Stock issuable upon exercise of the Warrants are called the “Warrant Shares,” and the Warrant Shares, together with the Warrants and the Shares, are called the Securities. The 21,425,000 Units to be sold by the Company are called the “Firm Units” and each Firm Unit is comprised of a “Firm Share” and a “Firm Warrant.” The respective amounts of the Firm Units to be purchased by each of the several Underwriters are set forth opposite their names on Schedule A hereto In addition, the Company has granted to the Underwriters an option to purchase (A) up to an additional 3,213,750 shares of Common Stock and (B) up to 3,213,750 additional warrants(which, if fully exercised, will result in the issuance of 1,606,875 Warrant Shares) for the purpose of covering over allotments in connection with the sale of the Firm Shares and Firm Warrants. The additional 3,213,750 Units to be sold by the Company pursuant to such option are collectively called the “Optional Units,” each Optional Unit consisting of an optional

Share (collectively, the “Optional Shares”) and an optional Warrant (collectively, the “Optional Warrants”). The Firm Units and, if and to the extent such option is exercised, the Optional Units are collectively called the “Offered Units.” ▇▇▇▇▇ and Company, LLC (“Cowen”), JMP Securities LLC (“JMP”) and ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”), have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Units.

A registration statement of the Company on Form S-3 (File No. 333-182975) (including such amendments and supplements thereto as may have been filed before execution of this Agreement, the “Registration Statement”) in respect of the Shares and Warrants has been filed with the Securities and Exchange Commission (the “Commission”) pursuant to Rule 415 under the Securities Act of 1933, as amended (the “Securities Act”). The Company meets the requirements for use of Form S-3 under the Securities Act and the rules and regulations of the Commission thereunder (the “Rules and Regulations”). Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of the Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus dated September 19, 2012 describing the Offered Units and the offering thereof is called the “Preliminary Prospectus,” and the Preliminary Prospectus and any other preliminary prospectus that describes the Offered Units and the offering thereof and is used prior to the filing of the Prospectus (as defined below) is called a “preliminary prospectus.” The prospectus, in the form first used by the Underwriters to confirm sales of the Offered Units or in the form first made available to the Underwriters by the Company to meet requests of purchasers pursuant to Rule 173 under the Securities Act, is called the “Prospectus.” As used herein, “Applicable Time” is 8:15 a.m. (New York time) on September 20, 2012. As used herein, “free writing prospectus” has the meaning set forth in Rule 405 under the Securities Act, and “Time of Sale Prospectus” means the preliminary prospectus, as amended or supplemented immediately prior to the Applicable Time, together with the free writing prospectuses, if any, identified in Schedule B hereto, each “road show” (as defined in Rule 433 under the Securities Act), if any, related to the offering of the Units contemplated hereby that is a “written communication” (as defined in Rule 405 under the Securities Act) (each such road show, a “Road Show”), and the pricing information set forth in Schedule C hereto. Any reference herein to any Registration Statement, preliminary prospectus, Preliminary Prospectus or the Prospectus shall be deemed to refer to and include the documents incorporated by reference therein. Any reference to any amendment or supplement to any preliminary prospectus, Preliminary Prospectus or the Prospectus shall be deemed to refer to and include any documents filed after the date of such preliminary prospectus, Preliminary Prospectus or the Prospectus under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and incorporated by reference in such preliminary prospectus, Preliminary Prospectus or Prospectus, as the case may be. Any reference to any amendment to the Registration Statement shall be deemed to refer to and include any annual report of the Company filed pursuant to Section 13(a) or 15(d) of the Exchange Act after the date of this Agreement that is incorporated by reference in the Registration Statement.

All references in this Agreement to the Registration Statement, the 462(b) Registration Statement, any Preliminary Prospectus, a preliminary prospectus, or the Prospectus, or any amendments or supplements to any of the foregoing, shall include any copy thereof filed with the Commission pursuant to its Electronic Data Gathering, Analysis and Retrieval System (“▇▇▇▇▇”).

The Company hereby confirms its agreements with the Underwriters as follows:

Section 1. Representations and Warranties of the Company. The Company hereby represents, warrants and covenants to each Underwriter, as of the date of this Agreement, as of the Firm Unit Closing Date (as hereinafter defined) and as of each Optional Unit Closing Date (as hereafter defined), if any, and covenants with each Underwriter, as follows:

(a) Compliance with Registration Requirements. The Registration Statement and any Rule 462(b) Registration Statement have been declared effective by the Commission under the Securities Act. The Company has complied, to the Commission’s satisfaction, with all requests of the Commission for additional or supplemental information. No stop order suspending the effectiveness of the Registration Statement or any post-effective amendment thereto or any Rule 462(b) Registration Statement is in effect and no proceedings for such purpose have been instituted or are pending or, to the Company’s knowledge, are contemplated or threatened by the Commission. The Company meets the requirements for use of Form S-3 under the Securities Act. The Company is eligible to make offerings of the Common Stock pursuant to General Instruction 1.B.1 of Form S-3.

Each preliminary prospectus and the Prospectus when filed complied or will comply in all material respects with the Securities Act and, if filed by electronic transmission pursuant to ▇▇▇▇▇ (except as may be permitted by Regulation S-T under the Securities Act), was identical to the copy thereof delivered to the Underwriters for use in connection with the offer and sale of the Offered Units. Each of the Registration Statement, any Rule 462(b) Registration Statement and any post-effective amendment thereto as of its respective effective time and at all subsequent times during the period beginning on the date hereof and ending on the later of the Optional Unit Closing Date or such date, as in the opinion of counsel for the Underwriters, the Prospectus is no longer required by law to be delivered (assuming the absence of Rule 172 under the Securities Act), in connection with sales by the Underwriters or a dealer (the “Prospectus Delivery Period”) complied and will comply in all material respects with the Securities Act and did not and will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading. As of the Applicable Time, the Time of Sale Prospectus (including any preliminary prospectus wrapper) did not, and at the time of each sale of the Offered Units and at the Firm Unit Closing Date (as defined in Section 2), the Time of Sale Prospectus, as then amended or supplemented by the Company, if applicable, will not, contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading. The Prospectus (including any Prospectus wrapper), as amended or supplemented, as of its date and at all subsequent times during the Prospectus Delivery Period, did not and will not contain any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. The documents incorporated by reference in the Prospectus, when they became effective or were filed with the Commission, as the case may be, conformed in all material respects to the requirements of the Securities Act or the Exchange Act, as applicable, and the rules and regulations of the Commission thereunder and none of such documents contained any untrue statement of a material fact or omitted to state any material fact required to be stated therein or necessary to make the statements therein in light of the circumstances under which they were made, not misleading; and any further documents so filed and incorporated by reference in the Prospectus, when such documents are filed with Commission will conform in all material respects to the requirements of the Securities Act or the Exchange Act, as applicable, and the rules and regulations of the Commission thereunder and will not contain any untrue statement of a material fact or omit to state any material fact required to be

stated therein or necessary to make the statements therein in light of the circumstances under which they were made, not misleading. The representations and warranties set forth in the four immediately preceding sentences do not apply to statements in or omissions from the Registration Statement, any Rule 462(b) Registration Statement, or any post-effective amendment thereto, or the Prospectus or the Time of Sale Prospectus, or any amendments or supplements thereto, made in reliance upon and in conformity with information relating to any Underwriter furnished to the Company in writing by the Representatives expressly for use therein, it being understood and agreed that the only such information furnished by the Representatives to the Company consists of the information described in Section 9(b) below. There are no contracts or other documents required to be described in the Time of Sale Prospectus or the Prospectus or to be filed as exhibits to the Registration Statement which have not been described or filed as required.

At the time of filing the Registration Statement and any post-effective amendments thereto, and at the date hereof, the Company was not, and the Company currently is not, an “ineligible issuer,” as defined in Rule 405 of the Rules and Regulations.

Any free writing prospectus that the Company is required to file pursuant to Rule 433(d) under the Securities Act has been, or will be, filed with the Commission in accordance with the requirements of the Securities Act. Each free writing prospectus that the Company has filed, or is required to file, pursuant to Rule 433(d) under the Securities Act or that was prepared by or behalf of or used or referred to by the Company complies or will comply in all material respects with the requirements of Rule 433 under the Securities Act including timely filing with the Commission or retention where required and legending, and each such free writing prospectus, as of its issue date and at all subsequent times through the completion of the public offer and sale of the Offered Units did not, does not and will not include any information that conflicted, conflicts with or will conflict with the information contained in the Registration Statement, the Prospectus or any preliminary prospectus, including any document incorporated by reference therein.

Except for the free writing prospectuses, if any, identified in Schedule B hereto, and electronic road shows, if any, furnished to you before first use, the Company has not prepared, used or referred to, and will not, without your prior consent, prepare, use or refer to, any free writing prospectus.

(b) Offering Materials Furnished to Underwriters. The Company has delivered to each Representative a complete copy of the Registration Statement, each amendment thereto and any Rule 462(b) Registration Statement and of each consent and certificate of experts filed as a part thereof, and conformed copies of the Registration Statement, each amendment thereto and any Rule 462(b) Registration Statement (without exhibits) and preliminary prospectuses, the Time of Sale Prospectus, the Prospectus, as amended or supplemented, and any free writing prospectus reviewed and consented to by the Representatives, in such quantities and at such places as the Representatives have reasonably requested for each of the Underwriters.

(c) Distribution of Offering Material By the Company. The Company has not distributed and will not distribute, prior to the later of (i) the expiration or termination of the option granted to the several Underwriters in Section 2 and (ii) the completion of the Underwriters’ distribution of the Offered Units, any offering material in connection with the offering and sale of the Offered Units other than a preliminary prospectus, the Time of Sale Prospectus, the Prospectus, any free writing prospectus reviewed and consented to by the Representatives, or the Registration Statement.

(d) The Underwriting Agreement. This Agreement has been duly authorized, executed and delivered by, and is a valid and binding agreement of, the Company, enforceable against the Company in accordance with its terms, except as rights to indemnification hereunder may be limited by applicable law and except as the enforcement hereof may be limited by bankruptcy, insolvency, reorganization, moratorium or other similar laws relating to or affecting the rights and remedies of creditors or by general equitable principles.

(e) Authorization of the Shares. The Shares have been duly authorized for issuance and sale pursuant to this Agreement and, when issued and delivered by the Company pursuant to this Agreement, will be validly issued, fully paid and non-assessable, and the issuance and sale of the Shares is not subject to any preemptive rights, rights of first refusal or other similar rights to subscribe for or purchase the Shares.

(f) Authorization of the Warrants and Warrant Shares. The Warrants have been duly authorized for issuance and sale pursuant to this Agreement and, when executed, issued and delivered by the Company pursuant to this Agreement against payment of the consideration set forth herein, will constitute legal, valid and binding obligations of the Company, enforceable against the Company in accordance with their terms, except as the enforcement thereof may be limited by bankruptcy, insolvency, reorganization, moratorium or other similar laws relating to or affecting the rights and remedies of creditors or by general equitable principles. The Warrant Shares issuable upon exercise of the Warrants have been duly authorized and validly reserved for issuance upon exercise of the Warrants in a number sufficient to meet the current exercise requirements. Upon exercise of the Warrants in accordance with their terms, the Warrant Shares issuable thereupon will be duly and validly issued and fully paid and non-assessable, and the issuance and sale of the Warrant Shares will not be subject to any preemptive rights, rights of first refusal or other similar rights to subscribe for or purchase the Warrant Shares.

(g) No Applicable Registration or Other Similar Rights. There are no persons with registration or other similar rights to have any equity or debt securities registered for sale under the Registration Statement or included in the offering contemplated by this Agreement, except for such rights as have been duly waived.

(h) No Material Adverse Change. Except as otherwise disclosed in the Time of Sale Prospectus, subsequent to the respective dates as of which information is given in the Time of Sale Prospectus: (i) there has been no material adverse change, or any development that could reasonably be expected to result in a material adverse change, in the condition, financial or otherwise, or in the earnings, business, operations or prospects, whether or not arising from transactions in the ordinary course of business, of the Company and its subsidiaries, considered as one entity (any such change is called a “Material Adverse Change”); (ii) the Company and its subsidiaries, considered as one entity, have not incurred any material liability or obligation, indirect, direct or contingent, not in the ordinary course of business nor entered into any material transaction or agreement not in the ordinary course of business; and (iii) there has been no dividend or distribution of any kind declared, paid or made by the Company or, except for dividends paid to the Company or other subsidiaries, any of its subsidiaries on any class of capital stock or repurchase or redemption by the Company or any of its subsidiaries of any class of capital stock.

(i) Independent Registered Public Accounting Firms. PricewaterhouseCoopers LLP, which has expressed its opinion with respect to the financial statements (which term as used in this Agreement includes the related notes thereto) and supporting schedules filed with the Commission or incorporated by reference as a part of the

Registration Statement and included in the Preliminary Prospectus, the Prospectus and Time of Sale Prospectus (each, an “Applicable Prospectus” and collectively, the “Applicable Prospectuses”), is (i) an independent registered public accounting firm as required by the Securities Act and the Exchange Act, (ii) in compliance with the applicable requirements relating to the qualification of accountants under Rule 2-01 of Regulation S-X and (iii) an independent registered public accounting firm as defined by the Public Company Accounting Oversight Board (the “PCAOB”) whose registration has not been suspended or revoked and, to the Company’s knowledge, who has not requested such registration to be withdrawn.

(j) Preparation of the Financial Statements.

(i) The financial statements filed with the Commission as a part of the Registration Statement and included in the Time of Sale Prospectus and the Prospectus (the “Company Financial Statements”) present fairly, in all material respects, the consolidated financial position of the Company and its subsidiaries as of and at the dates indicated and the results of their operations and cash flows for the periods specified. The supporting schedules to such Company Financial Statements included in the Registration Statement present fairly, in all material respects, the information required to be stated therein. Such Company Financial Statements and supporting schedules have been prepared in conformity with generally accepted accounting principles, as applied in the United States, applied on a consistent basis throughout the periods involved, except as may be expressly stated in the related notes thereto. Except as otherwise noted therein, the financial data set forth in each Applicable Prospectus under the captions “Ratios of Earnings to Fixed Charges”, “Selected Financial Data” and “Capitalization” fairly present, in all material respects, the information set forth therein on a basis consistent with that of the Company Financial Statements contained, incorporated or deemed to be incorporated in the Registration Statement.

(ii) No financial statements or supporting schedules are required to be included in the Registration Statement or any Applicable Prospectus which are not so included.

(iii) To the Company’s knowledge, no person who has been suspended or barred from being associated with a registered public accounting firm, or who has failed to comply with any sanction pursuant to Rule 5300 promulgated by the PCAOB, has participated in or otherwise aided the preparation of, or audited, the financial statements, supporting schedules or other financial data filed with the Commission as a part of the Registration Statement and included in any Applicable Prospectus.

(k) Interactive Data. The interactive data in eXtensible Business Reporting Language included or incorporated by reference in the each Registration Statement fairly presents the information called for in all material respects and has been prepared in accordance with the Commission’s rules and guidelines applicable thereto.

(l) Internal Control Over Financial Reporting. The Company and each of its subsidiaries make and keep books and records that are accurate in all material respects. The Company maintains a system of internal control over financial reporting (as such term is defined in Exchange Act Rule 13a-15(f)) that complies with the requirements of the Exchange Act (as defined below) applicable to the Company and has been designed by the Company’s principal executive officer and principal financial officer, or under their supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with U.S. generally accepted accounting

principles. The Company is not aware of any material weakness in the Company’s internal control over financial reporting (it being understood that this subsection shall not require the Company to comply with Section 404 of the Sarbanes Oxley Act of 2002 as of an earlier date than it would otherwise be required to so comply under applicable law). Except a disclosed in the Time of Sale Prospectus, since the date of the latest quarterly or annual financial statements included in the Time of Sale Prospectus, there has been no change in the Company’s internal control over financial reporting that has materially affected, or is reasonably likely to materially affect, the Company’s internal control over financial reporting.

(m) Incorporation and Good Standing of the Company and its Subsidiaries. Each of the Company and its subsidiaries has been duly incorporated or organized, as the case may be, and is validly existing as a corporation, partnership or limited liability company, as applicable, in good standing under the laws of the jurisdiction of its incorporation or organization and has the power and authority (corporate or other) to own, lease and operate its properties and to conduct its business as described in each Applicable Prospectus and, in the case of the Company, to enter into and perform its obligations under this Agreement, except where the failure to be in good standing would not reasonably be expected to result in a Material Adverse Change. Each of the Company and each subsidiary is duly qualified as a foreign corporation, partnership or limited liability company, as applicable, to transact business and is in good standing in, with respect to the Company and Horizon Pharma USA, Inc., the State of Illinois, and with respect to each of the Company and each of its subsidiaries, each other jurisdiction in which such qualification is required, whether by reason of the ownership or leasing of property or the conduct of business, except where the failure to be so qualified or in good standing would not reasonably be expected to result in a Material Adverse Change. All of the issued and outstanding capital stock or other equity or ownership interests of each of the Company’s subsidiaries have been duly authorized and validly issued, are fully paid and non-assessable and, except as set forth in the Time of Sale Prospectus, are owned by the Company, directly or through subsidiaries, free and clear of any security interest, mortgage, pledge, lien, encumbrance or adverse claim. The Company does not own or control, directly or indirectly, any corporation, association or other entity other than (i) the subsidiaries listed in Exhibit 21.1 to the Company’s Form 10-K for the fiscal year ended December 31, 2011and (ii) such other entities omitted from Exhibit 21.1 which, when such omitted entities are considered in the aggregate as a single subsidiary, would not constitute a “significant subsidiary” within the meaning of Rule 1-02(w) of Regulation S-X.

(n) Capitalization and Other Capital Stock Matters. Since the most recent date such information was included in the Prospectus, there has been no material change in the authorized, issued and outstanding capital stock of the Company (other than for subsequent issuances, if any, pursuant to employee benefit plans described in the Time of Sale Prospectus, upon the exercise of outstanding options or warrants described in the Time of Sale Prospectus, as a result of sales of Offered Units hereunder or as otherwise described in any document incorporated by reference in the Prospectus). The Common Stock (including the Shares) conforms in all material respects to the description thereof contained in the Time of Sale Prospectus. All of the issued and outstanding shares of Common Stock have been duly authorized and validly issued, are fully paid and non-assessable and have been issued in compliance with federal and state securities laws. None of the outstanding shares of Common Stock were issued in violation of any preemptive rights, rights of first refusal or other similar rights to subscribe for or purchase securities of the Company. Except as may have been issued pursuant to the Company’s stock option and other stock plans or arrangements described in the Time of Sale Prospectus, there are no authorized or outstanding options, warrants, preemptive rights, rights of first refusal or other rights to purchase, or equity or debt securities convertible into or exchangeable or exercisable for, any capital stock of the Company or any of its

subsidiaries other than those accurately described in the Time of Sale Prospectus. The description of the Company’s stock option, stock bonus and other stock plans or arrangements, and the options or other rights granted thereunder, set forth in each Applicable Prospectus accurately and fairly presents, in all material respects, the information required to be shown with respect to such plans, arrangements, options and rights. All grants of options to acquire shares of Common Stock (each, a “Company Stock Option”) were validly issued and approved by the Board of Directors of the Company, a committee thereof or an individual with authority duly delegated by the Board of Directors of the Company or a committee thereof. Grants of Company Stock Options were (i) made in material compliance with all applicable laws and (ii) as a whole, made in material compliance with the terms of the plans under which such Company Stock Options were issued. There is no and has been no policy or practice of the Company to coordinate the grant of Company Stock Options with the release or other public announcement of material information regarding the Company or its results of operations or prospects.

(o) Stock Exchange Listing. The Shares have been approved for listing on the Nasdaq Global Market, subject only to official notice of issuance.

(p) Non-Contravention of Existing Instruments; No Further Authorizations or Approvals Required. Neither the Company nor any of its subsidiaries is in violation of its charter or by laws, partnership agreement or operating agreement or similar organizational document, as applicable, or is in default (or, with the giving of notice or lapse of time, would be in default) (“Default”) under any indenture, mortgage, loan or credit agreement, note, contract, franchise, lease or other instrument to which the Company or any of its subsidiaries is a party or by which it or any of them may be bound (including, without limitation, any credit agreement, indenture, pledge agreement, security agreement or other instrument or agreement evidencing, guaranteeing, securing or relating to indebtedness of the Company or any of its subsidiaries ), or to which any of the property or assets of the Company or any of its subsidiaries is subject (each, an “Existing Instrument”), except for such Defaults as would not reasonably be expected to, individually or in the aggregate, result in a Material Adverse Change. The Company’s execution, delivery and performance of this Agreement, consummation of the transactions contemplated hereby and by the Prospectus and the issuance and sale of the Offered Units (i) have been duly authorized by all necessary corporate action and will not result in any violation of the provisions of the charter or by laws, partnership agreement or operating agreement or similar organizational document of the Company or any subsidiary, as applicable, (ii) will not conflict with or constitute a breach of, or Default under, or result in the creation or imposition of any lien, charge or encumbrance upon any property or assets of the Company or any of its subsidiaries pursuant to, or require the consent of any other party to, any Existing Instrument, except for such breaches, Defaults or results, or failure to obtain such consent, as would not reasonably be expected, individually or in the aggregate, to result in a Material Adverse Change and (iii) will not, assuming the Underwriters’ compliance with their obligations under this Agreement, result in any violation of any law, administrative regulation or administrative or court decree applicable to the Company or any subsidiary, except for such violations as would not reasonably be expected, individually or in the aggregate, to result in a Material Adverse Change. No consent, approval, authorization or other order of, or registration or filing with, any court or other governmental or regulatory authority or agency, is required for the Company’s execution, delivery and performance of this Agreement and consummation of the transactions contemplated hereby and by the Prospectus, except such as have been obtained or made or will be made by the Company under the Securities Act, or that may be required under applicable state securities or blue sky laws and from the Financial Industry Regulatory Authority (“FINRA”).

(q) No Material Actions or Proceedings. Except as disclosed in the Time of Sale Prospectus, there are no legal or governmental actions, suits or proceedings pending or, to the Company’s knowledge, threatened (i) against or affecting the Company or any of its subsidiaries, (ii) which have as the subject thereof any officer or director of, or property owned or leased by, the Company or any of its subsidiaries or (iii) relating to environmental or discrimination matters, where in any such case (A) to the Company’s knowledge there is a substantial likelihood that such action, suit or proceeding will be determined adversely to the Company, such subsidiary or such officer or director, (B) any such action, suit or proceeding, if so determined adversely, would reasonably be expected to result in a Material Adverse Change or adversely affect the consummation of the transactions contemplated by this Agreement or (C) any such action, suit or proceeding is or would be material in the context of the sale of Shares. No material labor dispute with the employees of the Company or any of its subsidiaries, exists or, to the Company’s knowledge, is threatened or imminent.

(r) Intellectual Property Rights. The Company and its subsidiaries own, possess or can acquire on reasonable terms sufficient trademarks, trade names, patent rights, copyrights, domain names, licenses, approvals, trade secrets and other similar rights (collectively, “Intellectual Property Rights”) reasonably necessary to conduct their businesses as now conducted; except to the extent failure to own, possess or acquire such Intellectual Property Rights would not result in a Material Adverse Change. Neither the Company nor any of its subsidiaries has received, or has any reason to believe that it will receive, any notice of infringement or conflict with asserted Intellectual Property Rights of others. Except as would not be reasonably likely to result, individually or in the aggregate, in a Material Adverse Change or except as disclosed in the Time of Sale Prospectus (i) to the Company’s knowledge, there is no infringement, misappropriation or violation by third parties of any of the Intellectual Property Rights owned by the Company; (ii) there is no pending or, to the Company’s knowledge, threatened action, suit, proceeding or claim by others challenging the rights of the Company and its subsidiaries in or to any such Intellectual Property Rights, and the Company is unaware of any facts which would form a reasonable basis for any such claim, that would, individually or in the aggregate, together with any other claims in this subsection (q) result in a Material Adverse Change; (iii) the Intellectual Property Rights owned by the Company and its subsidiaries and, to the Company’s knowledge, the Intellectual Property Rights licensed to the Company and its subsidiaries have not been adjudged by a court of competent jurisdiction invalid or unenforceable, in whole or in part, and there is no pending or, to the Company’s knowledge, threatened action, suit, proceeding or claim by others challenging the validity or scope of any such Intellectual Property Rights, and the Company is unaware of any facts which would form a reasonable basis for any such claim that would, individually or in the aggregate, together with any other claims in this subsection (q) result in a Material Adverse Change; (iv) there is no pending or, to the Company’s knowledge, threatened action, suit, proceeding or claim by others that the Company or its subsidiaries infringe, misappropriate or otherwise violate any Intellectual Property Rights or other proprietary rights of others, the Company and its subsidiaries have not received any written notice of such claim and the Company is unaware of any other facts which would form a reasonable basis for any such claim that would reasonably be expected, individually or in the aggregate, together with any other claims in this subsection (q) to result in a Material Adverse Change; and (v) to the Company’s knowledge, no employee of the Company or a subsidiary of the Company is in or has ever been in violation in any material respect of any term of any employment contract, patent disclosure agreement, invention assignment agreement, non-competition agreement, non-solicitation agreement, nondisclosure agreement or any restrictive covenant to or with a former employer where the basis of such violation relates to such employee’s employment with the Company or a subsidiary of the Company, or actions undertaken by the employee while employed with the Company or a subsidiary of the Company

and would reasonably be expected to result, individually or in the aggregate, in a Material Adverse Change. To the Company’s knowledge, all material technical information developed by and belonging to the Company and its subsidiaries for which they have not sought, and do not intend to seek, to patent or otherwise protect pursuant to applicable intellectual property laws has been kept confidential or disclosed only under obligations of confidentiality. The Company is not a party to or bound by any options, licenses or agreements with respect to the Intellectual Property Rights of any other person or entity that are required to be set forth in the Prospectus and are not described therein. None of the technology employed by the Company or any of its subsidiaries has been obtained or is being used by the Company or any of its subsidiaries in violation of any contractual obligation binding on the Company or any of its subsidiaries or, to the Company’s knowledge, any of its or its subsidiaries’ officers, directors or employees or otherwise in violation of the rights of any persons, except in each case for such violations that would not reasonably be expected to result in a Material Adverse Change.

(s) All Necessary Permits, etc. The Company and each subsidiary possess such valid and current certificates, authorizations or permits issued by the appropriate state, federal or foreign regulatory agencies or bodies necessary to conduct their respective businesses other than those the failure to possess or own would not result in a Material Adverse Change, and neither the Company nor any subsidiary has received, or has any reason to believe that it will receive, any notice of proceedings relating to the revocation or modification of, or non-compliance with, any such certificate, authorization or permit which, singly or in the aggregate, if the subject of an unfavorable decision, ruling or finding, would reasonably be expected to result in a Material Adverse Change.

(t) Title to Properties. The Company and each of its subsidiaries has good and marketable title to all of the real and personal property and other assets owned by it, in each case free and clear of any security interests, mortgages, liens, encumbrances, equities, adverse claims and other defects, except such as are disclosed in the Time of Sale Prospectus or as do not materially and adversely affect the value of such property and do not materially interfere with the use made or proposed to be made of such property by the Company or such subsidiary. To the Company’s knowledge, the real property, improvements, equipment and personal property held under lease by the Company or any subsidiary are held under valid and enforceable leases, with such exceptions as are not material and do not materially interfere with the use made or proposed to be made of such real property, improvements, equipment or personal property by the Company or such subsidiary.

(u) Tax Law Compliance. The Company and its consolidated subsidiaries have filed all necessary federal, state and foreign income and franchise tax returns or have properly requested extensions thereof and have paid all taxes required to be paid by any of them and, if due and payable, any related or similar assessment, fine or penalty levied against any of them except as may be being contested in good faith and by appropriate proceedings. The Company has made adequate charges, accruals and reserves in the applicable financial statements referred to in Section 1(i) above in respect of all federal, state and foreign income and franchise taxes for all periods as to which the tax liability of the Company or any of its consolidated subsidiaries has not been finally determined.

(v) Company Not an “Investment Company”. The Company has been advised of the rules and requirements under the Investment Company Act of 1940, as amended (the “Investment Company Act”). The Company is not, and will not be, either after receipt of payment for the Offered Units or after the application of the proceeds therefrom as described under “Use of Proceeds” in each Applicable Prospectus, an “investment company” within the

meaning of Investment Company Act and will conduct its business in a manner so that it will not become subject to the Investment Company Act.

(w) Insurance. Each of the Company and its subsidiaries are insured by recognized, financially sound and reputable institutions with policies in such amounts and with such deductibles and covering such risks as are generally deemed adequate and customary for the business for which it is engaged. The Company has no reason to believe that it or any subsidiary will not be able (i) to renew its existing insurance coverage as and when such policies expire or (ii) to obtain comparable coverage from similar institutions as may be necessary or appropriate to conduct its business as now conducted and at a cost that would not result in a Material Adverse Change. Neither the Company nor any subsidiary has been denied any insurance coverage material to the Company which it has sought or for which it has applied.

(x) No Price Stabilization or Manipulation; Compliance with Regulation M. The Company has not taken and will not take, directly or indirectly, any action designed to or that might be reasonably expected to cause or result in stabilization or manipulation of the price of the Shares or any other “reference security” (as defined in Rule 100 of Regulation M under the 1934 Act (“Regulation M”)) whether to facilitate the sale or resale of the Shares or Warrants or otherwise, and has taken no action which would directly or indirectly violate Regulation M. The Company acknowledges that the Underwriters may engage in passive market making transactions in the Shares on the Nasdaq Global Market in accordance with Regulation M.

(y) Related Party Transactions. There are no business relationships or related-party transactions involving the Company or any of its subsidiaries or any other person required to be described in each Applicable Prospectus which have not been described as required.

(z) FINRA Matters. All of the information provided to the Underwriters or to counsel for the Underwriters by the Company, its officers and directors and the holders of any securities (debt or equity) or options to acquire any securities of the Company in connection with letters, filings or other supplemental information provided to FINRA pursuant to FINRA Rule 5110 or FINRA Rule 5121 is true, complete and correct.

(aa) Parties to Lock-Up Agreements. Each of the Company’s directors and officers listed in Exhibit A hereto has executed and delivered to the Representatives a lock-up agreement substantially in the form of Exhibit B hereto. Exhibit A hereto contains a true, complete and correct list of all directors and officers of the Company. If any additional persons shall become directors or officers of the Company prior to the end of the Company Lock-up Period (as defined below), the Company shall cause each such person, prior to or contemporaneously with their appointment or election as a director or officer of the Company, to execute and deliver to the Representatives an agreement substantially in the form attached hereto as Exhibit B.

(bb) Statistical and Market-Related Data. The statistical, demographic and market-related data included in the Registration Statement and each Applicable Prospectus are based on or derived from sources that the Company believes to be reliable and accurate or represent the Company’s good faith estimates that are made on the basis of data derived from such sources.

(cc) No Unlawful Contributions or Other Payments. Neither the Company nor any of its subsidiaries nor, to the Company’s knowledge, any employee or agent of the

Company or any subsidiary, has made any contribution or other payment to any official of, or candidate for, any federal, state or foreign office in violation of any law or of the character required to be disclosed in the Registration Statement and each Applicable Prospectus and not so disclosed.

(dd) Disclosure Controls and Procedures; Deficiencies in or Changes to Internal Control Over Financial Reporting. The Company maintains a system of accounting controls sufficient to provide reasonable assurances that (i) transactions are executed in accordance with management’s general or specific authorization; (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles as applied in the United States and to maintain accountability for assets; (iii) access to assets is permitted only in accordance with management’s general or specific authorization; and (iv) the recorded accountability for assets is compared with existing assets at reasonable intervals and appropriate action is taken with respect to any differences. The Company has established and maintains disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)), which (i) are designed to ensure that material information relating to the Company, including its consolidated subsidiaries, is made known to the Company’s principal executive officer and its principal financial officer by others within those entities, during the periods in which the periodic reports required under the Exchange Act are being prepared; (ii) have been evaluated by management of the Company for effectiveness as of the end of the Company’s fiscal quarter ended June 30, 2012; and (iii) are effective in all material respects to perform the functions for which they were established. The Company is not aware of (i) any significant deficiencies or material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the Company’s ability to record, process, summarize and report financial information or (ii) any fraud, whether or not material, that involves management or other employees who have a significant role in the Company’s internal control over financial reporting.

(ee) Compliance with Environmental Laws. Except as described in the Time of Sale Prospectus and except as would not reasonably be expected to, individually or in the aggregate, result in a Material Adverse Change: (i) neither the Company nor any of its subsidiaries is in violation of any federal, state, local or foreign law or regulation relating to pollution or protection of human health or the environment (including, without limitation, ambient air, surface water, groundwater, land surface or subsurface strata) or wildlife, including without limitation, laws and regulations relating to emissions, discharges, releases or threatened releases of chemicals, pollutants, contaminants, wastes, toxic substances, hazardous substances, petroleum and petroleum products (collectively, “Materials of Environmental Concern”), or otherwise relating to the manufacture, processing, distribution, use, treatment, storage, disposal, transport or handling of Materials of Environment Concern (collectively, “Environmental Laws”), which violation includes, but is not limited to, noncompliance with any permits or other governmental authorizations required for the operation of the business of the Company or its subsidiaries under applicable Environmental Laws, or noncompliance with the terms and conditions thereof, nor has the Company or any of its subsidiaries received any written communication, whether from a governmental authority, citizens group, employee or otherwise, that alleges that the Company or any of its subsidiaries is in violation of any Environmental Law; (ii) there is no claim, action or cause of action filed with a court or governmental authority, no investigation with respect to which the Company has received written notice, and no written notice by any person or entity alleging potential liability for investigatory costs, cleanup costs, governmental responses costs, natural resources damages, property damages, personal injuries, attorneys’ fees or penalties arising out of, based on or resulting from the presence, or release into the environment, of any Material of Environmental Concern at any location owned, leased or

operated by the Company or any of its subsidiaries, now or in the past (collectively, “Environmental Claims”), pending or, to the Company’s knowledge, threatened against the Company or any of its subsidiaries or any person or entity whose liability for any Environmental Claim the Company or any of its subsidiaries has retained or assumed either contractually or by operation of law; and (iii) to the Company’s knowledge, there are no past or present actions, activities, circumstances, conditions, events or incidents, including, without limitation, the release, emission, discharge, presence or disposal of any Material of Environmental Concern, that reasonably could result in a violation of any Environmental Law or form the basis of a potential Environmental Claim against the Company or any of its subsidiaries or against any person or entity whose liability for any Environmental Claim the Company or any of its subsidiaries has retained or assumed either contractually or by operation of law.

(ff) ERISA Compliance. The Company and its subsidiaries and any “employee benefit plan” (as defined under the Employee Retirement Income Security Act of 1974, as amended, and the regulations and published interpretations thereunder (collectively, “ERISA”)) established or maintained by the Company, its subsidiaries or their “ERISA Affiliates” (as defined below) are in compliance in all material respects with ERISA. “ERISA Affiliate” means, with respect to the Company or a subsidiary, any member of any group of organizations described in Sections 414(b),(c),(m) or (o) of the Internal Revenue Code of 1986, as amended, and the regulations and published interpretations thereunder (the “Code”) of which the Company or such subsidiary is a member. No “reportable event” (as defined under ERISA) has occurred or is reasonably expected to occur with respect to any “employee benefit plan” established or maintained by the Company, its subsidiaries or any of their ERISA Affiliates. No “employee benefit plan” established or maintained by the Company, its subsidiaries or any of their ERISA Affiliates, if such “employee benefit plan” were terminated, would have any “amount of unfunded benefit liabilities” (as defined under ERISA). Neither the Company, its subsidiaries nor any of their ERISA Affiliates has incurred or reasonably expects to incur any liability under (i) Title IV of ERISA with respect to termination of, or withdrawal from, any “employee benefit plan” or (ii) Sections 412, 4971, 4975 or 4980B of the Code. Each “employee benefit plan” established or maintained by the Company, its subsidiaries or any of their ERISA Affiliates that is intended to be qualified under Section 401(a) of the Code is so qualified and nothing has occurred, whether by action or failure to act, which would reasonably be expected to result in the loss of such qualification.

(gg) Brokers. Except as contemplated by this Agreement, there is no broker, finder or other party that is entitled to receive from the Company any brokerage or finder’s fee or other fee or commission as a result of any transactions contemplated by this Agreement.

(hh) No Outstanding Loans or Other Extensions of Credit. There are no outstanding loans, advances (except normal advances for business expenses in the ordinary course of business) or guarantees or indebtedness by the Company to or for the benefit of any of the officers or directors of the Company or any of the members of any of them.

(ii) Compliance with Laws. The Company has not been advised, and has no reason to believe, that it and each of its subsidiaries are not conducting business in compliance with all applicable laws, rules and regulations of the jurisdictions in which it is conducting business, except where failure to be so in compliance would not result in a Material Adverse Change. The Company has not received any FDA Form 483, notice of adverse finding, warning letter, untitled letter or other correspondence or notice from the U.S. Food and Drug Administration or any other governmental authority alleging or asserting noncompliance with any laws applicable to the Company.

(jj) Dividend Restrictions. Except as described in the Time of Sale Prospectus or provided under credit facility agreements filed as exhibits to documents incorporated by reference in the Registration Statement, no subsidiary of the Company is prohibited or restricted, directly or indirectly, from paying dividends to the Company, or from making any other distribution with respect to such subsidiary’s equity securities or from repaying to the Company or any other subsidiary of the Company any amounts that may from time to time become due under any loans or advances to such subsidiary from the Company or from transferring any property or assets to the Company or to any other subsidiary.

(kk) No Reliance. The Company has not relied upon the Underwriters or legal counsel for the Underwriters for any legal, tax or accounting advice in connection with the offering and sale of the Offered Units.

(ll) Foreign Corrupt Practices Act. Neither the Company nor any of its subsidiaries nor, to the knowledge of the Company, any director, officer, agent, employee, affiliate or other person acting on behalf of the Company or any of its subsidiaries is aware of or has taken any action, directly or indirectly, that has resulted or would result in a violation of the Foreign Corrupt Practices Act of 1977, as amended, and the rules and regulations thereunder (the “FCPA”), including, without limitation, making use of the mails or any means or instrumentality of interstate commerce corruptly in furtherance of an offer, payment, promise to pay or authorization of the payment of any money, or other property, gift, promise to give, or authorization of the giving of anything of value to any “foreign official” (as such term is defined in the FCPA) or any foreign political party or official thereof or any candidate for foreign political office, in contravention of the FCPA; and the Company and its subsidiaries and, to the knowledge of the Company, the Company’s affiliates have conducted their respective businesses in compliance with the FCPA and have instituted and maintain policies and procedures designed to ensure, and which are reasonably expected to continue to ensure, continued compliance therewith.

(mm) Money Laundering Laws. The operations of the Company and its subsidiaries are, and have been conducted at all times, in compliance with applicable financial recordkeeping and reporting requirements of the Currency and Foreign Transactions Reporting Act of 1970, as amended, the money laundering statutes of all applicable jurisdictions, the rules and regulations thereunder and any related or similar applicable rules, regulations or guidelines, issued, administered or enforced by any governmental agency (collectively, the “Money Laundering Laws”) and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or any of its subsidiaries with respect to the Money Laundering Laws is pending or, to the best knowledge of the Company, threatened.

(nn) OFAC. Neither the Company nor any of its subsidiaries nor, to the knowledge of the Company, any director, officer, agent, employee, affiliate or person acting on behalf of the Company or any of its subsidiaries is currently subject to any U.S. sanctions administered by the Office of Foreign Assets Control of the U.S. Treasury Department (“OFAC”); and the Company will not directly or indirectly use the proceeds of this offering, or lend, contribute or otherwise make available such proceeds to any subsidiary, joint venture partner or other person or entity, for the purpose of financing the activities of any person currently subject to any U.S. sanctions administered by OFAC.

Any certificate contemplated hereby and signed by any officer of the Company or any of its subsidiaries and delivered to the Representatives or to counsel for the Underwriters shall be

deemed a representation and warranty by the Company to each Underwriter as to the matters covered thereby.

The Company acknowledges that the Underwriters and, for purposes of the opinions to be delivered pursuant to Section 6 hereof, counsel to the Company and counsel to the Underwriters, will rely upon the accuracy and truthfulness of the foregoing representations and hereby consents to such reliance.

Section 2. Purchase, Sale and Delivery of the Offered Units

(a) The Firm Units. The Company agrees to issue and sell to each of the Underwriters, and each of the Underwriters agrees, severally and not jointly, to purchase from the Company, at a purchase price per share of Common Stock of $3.2806 (the “Per Share Purchase Price”) and a purchase price per Warrant of $0.0094 (the “Per Warrant Purchase Price” and together with the Per Share Purchase Price, the “Unit Purchase Price”), the number of Firm Units set forth opposite the name of such Underwriter under the column “Number of Firm Units to be Purchased” on Schedule A.

(b) The Optional Units. The Company hereby grants to the several Underwriters an option to purchase, severally and not jointly, all or any part of the Optional Shares at the Per Share Purchase Price and/or Optional Warrants at the Per Warrant Purchase Price. The number of Optional Shares and Optional Warrants to be purchased by each Underwriter shall be the same percentage (adjusted by the Representatives to eliminate fractions) of the total number of Optional Shares and Optional Warrants to be purchased by the Underwriters as such Underwriter is purchasing of the Firm Shares and the Firm Warrants. Such option may be exercised only to cover over-allotments in the sales of the Firm Units by the Underwriters and may be exercised in whole or in part at any time on or before 12:00 noon, New York City time, on the business day before the Firm Units Closing Date (as defined below), and from time to time thereafter within 30 days after the date of this Agreement, in each case upon written, facsimile or telegraphic notice, or verbal or telephonic notice confirmed by written, facsimile or telegraphic notice, by the Representatives to the Company no later than 12:00 noon, New York City time, on the business day before the Firm Units Closing Date or at least two business days before the Optional Units Closing Date (as defined below), as the case may be, setting forth the number of Optional Shares and Optional Warrants to be purchased and the time and date (if other than the Firm Units Closing Date) of such purchase. The Representatives, in their sole discretion, shall determine the allocation and distribution of the Optional Shares and Optional Warrants. The Representatives may cancel the option at any time prior to its expiration by giving written notice of such cancellation to the Company.

(c) The Closing Dates. Payment of the purchase price for, and delivery of certificates for, the Firm Shares and Firm Warrants shall be made at the offices of ▇▇▇▇▇▇▇ Procter LLP, The New York Times Building, ▇▇▇ ▇▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇ ▇▇▇▇, ▇▇ ▇▇▇▇▇ (or such other place as may be agreed to by the Company and the Representatives) at 10:00 a.m. New York time, on September 25, 2012, or such other time and date not later than 1:30 p.m. New York time, on September 25, 2012 as the Representatives shall designate by notice to the Company (the time and date of such closing are called the “Firm Units Closing Date”). The Company hereby acknowledges that circumstances under which the Representatives may provide notice to postpone the Firm Units Closing Date as originally scheduled include, but are in no way limited to, any determination by the Company or the Representatives to recirculate to the public copies of an amended or supplemented Prospectus or a delay as contemplated by the provisions of Section 11. In addition, in the event that any or all of the Optional Shares and/or Optional

Warrants are purchased by the Underwriters, payment of the Per Share Purchase Price and/or the Per Warrant Purchase Price, and delivery of the certificates for such Optional Shares and/or Optional Warrants shall be made at the above-mentioned offices, or at such other place as shall be agreed upon by the Representatives and the Company, on each date of delivery as specified in the notice from the Representatives to the Company (such time and date of delivery and payment are called the “Optional Units Closing Date”). The Firm Units Closing Date and any Optional Units Closing Date are called, individually, a “Closing Date” and, together, the “Closing Dates.”

(d) Payment for the Offered Units. Payment shall be made to the Company by wire transfer of immediately available funds against delivery of the certificates to the Representatives for the respective accounts of the Underwriters for the Shares and Warrants to be purchased by them.

It is understood that the Representatives have been authorized, for their own accounts and the accounts of the several Underwriters, to accept delivery of and receipt for, and make payment of the purchase price for, the Shares and Warrants the Underwriters have agreed to purchase. Each of ▇▇▇▇▇, JMP and Stifel individually and not as the Representatives of the Underwriters, may (but shall not be obligated to) make payment for any Shares and Warrants to be purchased by any Underwriter whose funds shall not have been received by the Representatives by the Firm Units Closing Date or the applicable Optional Units Closing Date, as the case may be, for the account of such Underwriter, but any such payment shall not relieve such Underwriter from any of its obligations under this Agreement.

(e) Delivery of the Offered Units. Certificates evidencing the Shares and the Warrants shall be registered in such names and shall be in such denominations as the Representatives shall request at least two full business days before the Firm Units Closing Date or, in the case of Optional Units, on the day of notice of exercise of the option as described in Section 2(b) and, in the case of the Shares, be delivered by or on behalf of the Company to the Representatives through the facilities of the Depository Trust Company (“DTC”) for the account of the Underwriters and in the case of the Warrants, shall be delivered by the Company directly to the Representatives for the account of the Underwriters. The Company will cause the certificates representing the Shares and the Warrants to be made available for checking and packaging, at such place as is designated by the Representatives, on the full business day before the Firm Units Closing Date (or the Optional Units Closing Date in the case of the Optional Units). Time shall be of the essence, and delivery at the time and place specified in this Agreement is a further condition to the obligations of the Underwriters.

Section 3. Additional Covenants of the Company. The Company further covenants and agrees with each Underwriter as follows:

(a) Documents; Representatives’ Review of Proposed Amendments and Supplements. To prepare the Prospectus in a form reasonably acceptable to the Representatives containing information previously omitted at the time of effectiveness of the Registration Statement in reliance on Rules 430A, 430B or 430C of the Rules and Regulations and to file such Prospectus pursuant to Rule 424(b) of the Rules and Regulations not later than the second business (2nd) day following the execution and delivery of this Agreement or, if applicable, such earlier time as may be required by Rule 430A of the Rules and Regulations; to notify the Representatives promptly of the Company’s intention to file or prepare any supplement or amendment to any Registration Statement or to the Prospectus relating to the offering of the Offered Units and to make no amendment or supplement to the Registration Statement or to the Prospectus relating to the offering of the Offered Units to which the Representatives shall

reasonably object by notice to the Company after a reasonable period to review; to advise the Representatives, promptly after it receives notice thereof, of the time when any amendment to any Registration Statement has been filed or becomes effective or any supplement to the Prospectus or any amended Prospectus relating to the offering of the Offered Units has been filed and to furnish the Representatives with copies thereof; to file promptly all material required to be filed by the Company with the Commission pursuant to Rules 433(d) or 163(b)(2) of the Rules and Regulations, as the case may be; to file promptly all reports and any definitive proxy or information statements required to be filed by the Company with the Commission pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act during the Prospectus Delivery Period; to advise the Representatives during the Prospectus Delivery Period, promptly after it receives notice thereof, of the issuance by the Commission of any stop order or of any order preventing or suspending the use of any Preliminary Prospectus, any Issuer Free Writing Prospectus or the Prospectus, of the suspension of the qualification of the Shares or the Warrants for offering or sale in any jurisdiction, of the initiation or threatening of any proceeding for any such purpose, or of any request by the Commission for the amending or supplementing of the Registration Statement, the Time of Sale Prospectus or the Prospectus; and, in the event of the issuance of any stop order or of any order preventing or suspending the use of any Preliminary Prospectus, any Issuer Free Writing Prospectus or the Prospectus or suspending any such qualification during the Prospectus Delivery Period, to promptly to use its best efforts to obtain the withdrawal of such order.

(b) Delivery of Registration Statement, Time of Sale Prospectus and Prospectus. Upon the request of the Representatives, to the extent not available on ▇▇▇▇▇, the Company shall furnish to you, without charge, two copies of the Registration Statement, any amendments thereto and any Rule 462(b) Registration Statement (including exhibits thereto) and shall furnish to you in New York City, without charge, prior to 10:00 a.m. New York City time on the business day next succeeding the date of this Agreement and during the period mentioned in Section 3(e) or 3(f) below, as many copies of the Time of Sale Prospectus, the Prospectus and any supplements and amendments thereto or to the Registration Statement as you may reasonably request.

(c) Free Writing Prospectuses. The Company shall furnish to the Representatives for review, a reasonable amount of time prior to the proposed time of filing or use thereof, a copy of each proposed free writing prospectus or any amendment or supplement thereto to be prepared by or on behalf of, used by, or referred to by the Company and the Company shall not file, use or refer to any proposed free writing prospectus or any amendment or supplement thereto without the Representatives’ consent; provided that the prior written consent of the Representatives hereto shall be deemed to have been given in respect of the Issuer Free Writing Prospectuses included in Schedule B hereto. The Company shall furnish to each Underwriter, without charge, as many copies of any free writing prospectus prepared by or on behalf of, or used by the Company, as such Underwriter may reasonably request. If during the Prospectus Delivery Period there occurred or occurs an event or development as a result of which any free writing prospectus prepared by or on behalf of, used by, or referred to by the Company conflicted or would conflict with the information contained in the Registration Statement or included or would include an untrue statement of a material fact or omitted or would omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances prevailing at that subsequent time, not misleading, the Company shall promptly amend or supplement such free writing prospectus to eliminate or correct such conflict or so that the statements in such free writing prospectus as so amended or supplemented will not include an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances prevailing at such subsequent time, not

misleading, as the case may be; provided, however, that prior to amending or supplementing any such free writing prospectus, the Company shall furnish to the Representatives for review, a reasonable amount of time prior to the proposed time of filing or use thereof, a copy of such proposed amended or supplemented free writing prospectus and the Company shall not file, use or refer to any such amended or supplemented free writing prospectus without the Representatives’ consent.

(d) Filing of Underwriter Free Writing Prospectuses. The Company shall not take any action that would result in any Underwriter or the Company being required to file with the Commission pursuant to Rule 433(d) under the Securities Act a free writing prospectus prepared by or on behalf of the Underwriters that the Underwriters otherwise would not have been required to file thereunder.

(e) Cease Use of Free Writing Prospectus. If at any time following issuance of a free writing prospectus in connection with the offering of the Offered Units there occurred or occurs an event or development as a result of which such free writing prospectus conflicted or will conflict with the information contained in the Registration Statement, Time of Sale Prospectus or Prospectus, including any document incorporated by reference therein and any prospectus supplement deemed to be a part thereof and not superseded or modified or included or would include an untrue statement of a material fact or omitted or would omit to state a material fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, the Company has promptly notified or will promptly notify the Representatives so that any use of such free writing prospectus may cease until it is amended or supplemented and has promptly amended or will promptly amend or supplement, at its own expense, such free writing prospectus to eliminate or correct such conflict, untrue statement or omission.

(f) Amendments and Supplements to Time of Sale Prospectus. If the Time of Sale Prospectus is being used to solicit offers to buy the Offered Units at a time when the Prospectus is not yet available to prospective purchasers and any event shall occur or condition exist as a result of which it is necessary to amend or supplement the Time of Sale Prospectus so that the Time of Sale Prospectus does not include an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances when delivered to a prospective purchaser, not misleading, or if any event shall occur or condition exist as a result of which the Time of Sale Prospectus conflicts with the information contained in the Registration Statement, or if, in the opinion of the Company, counsel for the Company, the Representatives or counsel for the Underwriters, it is necessary to amend or supplement the Time of Sale Prospectus to comply with applicable law, including the Securities Act, the Company shall (subject to Sections 3(b) and 3(c)) promptly prepare, file with the Commission and furnish, at its own expense, to the Underwriters and to any dealer upon request, either amendments or supplements to the Time of Sale Prospectus so that the statements in the Time of Sale Prospectus as so amended or supplemented will not include an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances when delivered to a prospective purchaser, not misleading or so that the Time of Sale Prospectus, as amended or supplemented, will no longer conflict with the Registration Statement, or so that the Time of Sale Prospectus, as amended or supplemented, will comply with applicable law including the Securities Act.

(g) Securities Act Compliance. During the Prospectus Delivery Period, the Company shall promptly advise the Representatives in writing (i) of the receipt of any comments of, or requests for additional or supplemental information from, the Commission, (ii) of the time

and date of any filing or post-effective amendment to the Registration Statement, any Rule 462(b) Registration Statement or any amendment or supplement to any preliminary prospectus, the Time of Sale Prospectus, any free writing prospectus or the Prospectus, (iii) of the time and date that any post-effective amendment to the Registration Statement or any Rule 462(b) Registration Statement becomes effective.

(h) Amendments and Supplements to the Prospectus and Other Securities Act Matters. If, at any time during the Prospectus Delivery Period, any event shall occur or condition exist as a result of which it is necessary to amend or supplement the Prospectus so that the Prospectus does not include an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances when the Prospectus is delivered to a purchaser, not misleading, or if in the opinion of the Company, counsel for the Company, the Representatives or counsel for the Underwriters it is otherwise necessary to amend or supplement the Prospectus to comply with applicable law, including the Securities Act, the Company agrees (subject to Sections 3(b) and 3(c)) to promptly prepare, file with the Commission and furnish at its own expense to the Underwriters and to any dealer upon request, amendments or supplements to the Prospectus so that the statements in the Prospectus as so amended or supplemented will not include an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances when the Prospectus is delivered to a purchaser, not misleading or so that the Prospectus, as amended or supplemented, will comply with applicable law including the Securities Act. Neither the Representatives’ consent to, or delivery of, any such amendment or supplement shall constitute a waiver of any of the Company’s obligations under Sections 3(b) or 3(c).

(i) Blue Sky Compliance. The Company shall cooperate with the Representatives and counsel for the Underwriters to qualify or register the Offered Units for sale under (or obtain exemptions from the application of) the state securities or blue sky laws or Canadian provincial securities laws of those jurisdictions designated by the Representatives, shall comply with such laws and shall continue such qualifications, registrations and exemptions in effect so long as required for the distribution of the Shares and Warrants; provided that the Company shall not be required to qualify as a foreign corporation or to take any action that would subject it to general service of process in any such jurisdiction where it is not presently qualified or where it would be subject to taxation as a foreign corporation. The Company will advise the Representatives promptly of the suspension of the qualification or registration of (or any such exemption relating to) the Shares and Warrants for offering, sale or trading in any jurisdiction or any initiation or threat of any proceeding for any such purpose, and in the event of the issuance of any order suspending such qualification, registration or exemption, the Company shall use its best efforts to obtain the withdrawal thereof at the earliest possible moment.

(j) Use of Proceeds. The Company shall apply the net proceeds from the sale of the Offered Units sold by it in the manner described under the caption “Use of Proceeds” in each Applicable Prospectus.

(k) Transfer Agent. The Company shall engage and maintain, at its expense, a registrar and transfer agent for the Shares and Warrants.

(l) Earnings Statement. To make generally available to its stockholders as soon as practicable, but in any event not later than sixteen (16) months after the effective date of the Registration Statement (as defined in Rule 158(c) of the Rules and Regulations), an earnings statement of the Company and its subsidiaries (which need not be audited) complying with

Section 11(a) of the Securities Act and the Rules and Regulations (including, at the option of the Company, Rule 158).

(m) ▇▇▇▇▇▇▇▇-▇▇▇▇▇. To at all times comply in all material respects with applicable provisions of the ▇▇▇▇▇▇▇▇-▇▇▇▇▇ Act in effect from time to time.

(n) Listing. The Company will use its best efforts to list, subject to notice of issuance, the Shares on the Nasdaq Global Market and to maintain the listing of the Shares on the Nasdaq Global Market.

(o) Agreement Not to Offer or Sell Additional Shares. That the Company will not, for a period of ninety (90) days from the date of this Agreement, (the “Lock-Up Period”) without the prior written consent of the Representatives, directly or indirectly offer, sell, assign, transfer, pledge, contract to sell, or otherwise dispose of, or announce the intention to otherwise dispose of, any Shares or any securities convertible into or exercisable or exchangeable for Shares, other than the Company’s sale of the Offered Units hereunder or pursuant to or in connection with (i) employee benefit plans, equity compensation plans or other compensation plans as in existence on the date hereof and as described in the Time of Sale Prospectus, (ii) currently outstanding options, warrants or rights or the Warrants, (iii) beginning on the 31st day after the date of this Agreement, the sale and issuance of Shares pursuant to that certain Sales Agreement, dated as of August 14, 2012, by and between the Company and ▇▇▇▇▇, or (iv) a bona fide strategic partnership, joint venture, collaboration, merger or acquisition or license of any business or assets of a third party; provided that the total number of shares of Common Stock, including shares underlying convertible or exercisable securities, that may be issued pursuant to this clause (iv) may not exceed ten percent (10%) of the number of outstanding shares of Common Stock immediately following the completion of the offering contemplated by this Agreement. The Company also agrees that during such period, other than for the sale of the Offered Units hereunder, the Company will not file any registration statement, preliminary prospectus or prospectus, or any amendment or supplement thereto, under the Securities Act for any such transaction or which registers, or offers for sale, Units or any securities convertible into or exercisable or exchangeable for Units, Shares or Warrants; provided, however, the foregoing limitation shall not apply to the filing of any registration statement on Form S-8 in respect of any equity compensation plans or arrangements maintained by the Company. If (i) the Company issues an earnings release or material news or a material event relating to the Company occurs, during the last 17 days of the Lock-Up Period, or (ii) prior to the expiration of the Lock-Up Period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the Lock-Up Period, the Lock-Up Period shall be extended and the restrictions imposed by this Agreement shall continue to apply until the expiration of the 18-day period beginning on the date of the issuance of the earnings release or the occurrence of the material news or material event except that such extension will not apply if, (A) the Company’s common stock is an “actively traded security” (as defined in Regulation M under the Exchange Act), (B) the Company meets the applicable requirements of Rule 139(a)(1) under the Securities Act in the manner contemplated by NASD Conduct Rule 2711(f)(4) and (C) the provisions of NASD Conduct Rule 2711(f)(4) do not restrict the publication or distribution by the Underwriters of any research reports relating to the Company during the 15 days before or after the last day of the Lock-Up Period (before giving effect to such extension). The Company will provide the Representatives with prior notice of any such announcement that gives rise to an extension of the Lock-Up Period.

(p) Future Reports to the Representatives. Upon request, during the period of five (5) years from the date hereof, to the extent not available on ▇▇▇▇▇, to deliver to each of

the Underwriters, (i) as soon as they are available, copies of all reports or other communications furnished to stockholders generally, and (ii) as soon as they are available, copies of any reports and financial statements furnished or filed with the Commission or any national securities exchange on which the Common Stock is listed. However, so long as the Company is subject to the reporting requirements of either Section 13 or Section 15(d) of the Exchange Act and is timely filing reports with the Commission on ▇▇▇▇▇, it is not required to furnish such reports or statements to the Underwriters.

(q) Investment Limitation. The Company shall not invest, or otherwise use the proceeds received by the Company from its sale of the Offered Units in such a manner as would require the Company or any of its subsidiaries to register as an investment company under the Investment Company Act.

(r) No Stabilization or Manipulation; Compliance with Regulation M. The Company will not take, directly or indirectly, any action designed to or that might be reasonably expected to cause or result in stabilization or manipulation of the price of the Shares or any other reference security, whether to facilitate the sale or resale of the Offered Units, Shares, Warrants or otherwise, and the Company will, and shall cause each of its affiliates to, comply with all applicable provisions of Regulation M. If the limitations of Rule 102 of Regulation M (“Rule 102”) do not apply with respect to the Offered Units or any other reference security pursuant to any exception set forth in Section (d) of Rule 102, then promptly upon notice from the Representatives (or, if later, at the time stated in the notice), the Company will, and shall cause each of its affiliates to, comply with Rule 102 as though such exception were not available but the other provisions of Rule 102 (as interpreted by the Commission) did apply.

(s) Existing Lock-Up Agreements. During the Lock-up Period, the Company will enforce all existing agreements between the Company and any of its security holders that prohibit the sale, transfer, assignment, pledge or hypothecation of any of the Company’s securities. In addition, the Company will direct the transfer agent to place stop transfer restrictions upon any such securities of the Company that are bound by such existing “lock-up” agreements for the duration of the periods contemplated in such agreements, including, without limitation, “lock-up” agreements entered into by the Company’s officers, directors and other persons and entities listed in Exhibit A hereto pursuant to Section 6(i).

The Representatives, on behalf of the several Underwriters, may, in their sole discretion, waive in writing the performance by the Company of any one or more of the foregoing covenants or extend the time for their performance.

Section 4. Payment of Expenses. The Company agrees to pay all costs and expenses incurred in connection with the performance of its obligations hereunder and in connection with the transactions contemplated hereby, including without limitation: (i) all costs, fees and expenses incident to the issuance and delivery of the Shares and Warrants (including all printing and engraving costs), (ii) all fees and expenses of the registrar and transfer agent of the Shares and Warrants, (iii) all necessary issue, transfer and other stamp taxes in connection with the issuance and sale of the Shares and Warrants to the Underwriters, (iv) all fees and expenses of the Company’s counsel, independent public or certified public accountants and other advisors, (v) all costs and expenses incurred in connection with the preparation, printing, filing, shipping and distribution of the Registration Statement (including financial statements, exhibits, schedules, consents and certificates of experts), the Time of Sale Prospectus, the Prospectus, any free writing prospectus prepared by or on behalf of, used by, or referred to by the Company, and each preliminary prospectus, and all amendments and supplements thereto, and this Agreement, (vi) all

filing fees, attorneys’ fees and expenses incurred by the Company or the Underwriters (subject to clause (x) below), in connection with qualifying or registering (or obtaining exemptions from the qualification or registration of) all or any part of the Shares and Warrants for offer and sale under the state securities or blue sky laws or the provincial securities laws of Canada, and, if requested by the Representatives, preparing and printing a “Blue Sky Survey” or memorandum and a “Canadian wrapper”, and any supplements thereto, advising the Underwriters of such qualifications, registrations, determinations and exemptions, (vii) the filing fees incident to, and the reasonable fees and expenses of counsel for the Underwriters in connection with, FINRA’s review, if any, and approval of the Underwriters’ participation in the offering and distribution of the Offered Units (subject to clause (x) below), (viii) the costs and expenses of the Company relating to investor presentations on any “road show” undertaken in connection with the marketing of the offering of the Offered Units, including, without limitation, expenses associated with the preparation or dissemination of any electronic road show, expenses associated with the production of road show slides and graphics, fees and expenses of any consultants engaged in connection with the road show presentations with the prior approval of the Company, travel and lodging expenses of the representatives, employees and officers of the Company and any such consultants, (ix) the fees and expenses associated with listing the Shares on the Nasdaq Global Market, (x) the out-of-pocket expenses of the Underwriters arising out of the offering contemplated by this Agreement (including the reasonable and documented fees of counsel to the Underwriters) and not otherwise provided in this Section 4; provided, however, that the aggregate amount reimbursed by the Company pursuant to clauses (vi), (vii) and this clause (x) shall not exceed $100,000, and (xi) all other fees, costs and expenses of the nature referred to in Item 13 of Part II of the Registration Statement. Except as provided in this Section 4, Section 7, Section 9 and Section 10 hereof, the Underwriters shall pay their own expenses, including the fees and disbursements of their counsel.

Section 5. Covenant of the Underwriters. Each Underwriter severally and not jointly, covenants with the Company not to take any action that would result in the Company being required to file with the Commission pursuant to Rule 433(d) under the Securities Act a free writing prospectus prepared by or on behalf of such Underwriter that otherwise would not be required to be filed by the Company thereunder, but for the action of such Underwriter.

Section 6. Conditions of the Obligations of the Underwriters. The obligations of the several Underwriters to purchase and pay for the Firm Units as provided herein on the Firm Units Closing Date and, with respect to the Optional Units, each Optional Units Closing Date, shall be subject to the accuracy of the representations and warranties on the part of the Company set forth in Section 1 hereof as of the date hereof and as of the Firm Units Closing Date as though then made and, with respect to the Optional Units, as of each Optional Units Closing Date as though then made, to the timely performance by the Company of its covenants and other obligations hereunder, and to each of the following additional conditions:

(a) Accountants’ Comfort Letters. On the date hereof, the Representatives shall have received from PricewaterhouseCoopers LLP, independent registered public accounting firm for the Company, (i) a letter dated the date hereof addressed to the Underwriters, in form and substance satisfactory to the Representatives, containing statements and information of the type ordinarily included in accountant’s “comfort letters” to underwriters, delivered according to Statement of Auditing Standards No. 72 (or any successor bulletin), with respect to the audited and unaudited financial statements and certain financial information contained in the Registration Statement, the Preliminary Prospectus, Time of Sale Prospectus, and each free writing prospectus, if any, and, with respect to each letter dated the date hereof only, the Prospectus (and the Representatives shall have received an additional two conformed copies of such accountants’

letter for each of the several Underwriters), and (ii) confirming that they are (A) independent public or certified public accountants as required by the Securities Act and (B) in compliance with the applicable requirements relating to the qualification of accountants under Rule 2-01 of Regulation S-X.

(b) Compliance with Registration Requirements; No Stop Order; No Objection from FINRA. For the period from and after effectiveness of this Agreement and prior to the Firm Unit Closing Date and, with respect to the Optional Shares, each Optional Unit Closing Date:

(i) the Prospectus (including the information required by Rule 430A, 430B and 430C under the Securities Act) shall have been filed with the Commission within the applicable time period prescribed for such filing by, and in compliance with, the Rules and Regulations, and the Rule 462(b) Registration Statement, if any, shall have become effective immediately upon its filing with the Commission;

(ii) no stop order suspending the effectiveness of the Registration Statement, any Rule 462(b) Registration Statement, or any post-effective amendment to the Registration Statement, shall be in effect and no proceedings for such purpose shall have been instituted or threatened by the Commission, and all requests for additional information on the part of the Commission (to be included or incorporated by reference in the Registration Statement or the Prospectus) shall have been complied with to the reasonable satisfaction of the Representatives; and

(iii) FINRA shall have raised no objection to the fairness and reasonableness of the underwriting terms and arrangements.

(c) No Material Adverse Change. For the period from and after the date of this Agreement and through and including the Firm Units Closing Date and, with respect to the Optional Shares, each Optional Units Closing Date, in the judgment of the Representatives there shall not have occurred any Material Adverse Change.

(d) Opinion of Counsel for the Company. On each of the Firm Units Closing Date and each Optional Units Closing Date the Representatives shall have received the opinion and negative assurance letter of ▇▇▇▇▇▇ LLP, counsel for the Company, dated as of such Closing Date, the forms of which are attached as Exhibit D-1 and Exhibit D-2, respectively.

(e) Opinion of Intellectual Property Counsel for the Company. On each of the Firm Units Closing Date and each Optional Units Closing Date the Representative shall have received the opinion of Global Patent Group, intellectual property counsel for the Company, dated as of such Closing Date, with respect to certain intellectual property matters, the form of which is attached as Exhibit E.

(f) Opinion of Counsel for the Underwriters. On each of the Firm Units Closing Date and each Optional Units Closing Date the Representatives shall have received the opinion and negative assurance letter of ▇▇▇▇▇▇▇ Procter LLP, counsel for the Underwriters, in form and substance satisfactory to the Underwriters, dated as of such Closing Date.

(g) Officers’ Certificate. On each of the Firm Units Closing Date and each Optional Units Closing Date the Representatives shall have received a written certificate executed by the Chief Executive Officer or President of the Company and the Chief Financial Officer of

the Company, dated as of such Closing Date, to the effect set forth in subsection (b)(ii) of this Section 6, and further to the effect that:

(i) for the period from and including the date of this Agreement through and including such Closing Date, there has not occurred any Material Adverse Change;

(ii) the representations, warranties and covenants of the Company set forth in Section 1 of this Agreement are true and correct with the same force and effect as though expressly made on and as of such Closing Date; and

(iii) the Company has complied with all the agreements hereunder and satisfied all the conditions on its part to be performed or satisfied hereunder at or prior to such Closing Date; and

(h) Secretary’s Certificate. The Company shall have furnished to the Underwriters a Secretary’s Certificate of the Company, in form and substance reasonably satisfactory to counsel for the Underwriters and customary for the type of offering contemplated by this Agreement.

(i) Bring-down Comfort Letter. On each of the Firm Units Closing Date and each Optional Units Closing Date the Representatives shall have received from PricewaterhouseCoopers LLP, independent public or certified public accountants for the Company, a letter dated such date, in form and substance satisfactory to the Representatives, to the effect that they reaffirm the statements made in the letter furnished by them pursuant to subsection (a) of this Section 6, except that the specified date referred to therein for the carrying out of procedures shall be no more than five business days prior to the Firm Units Closing Date or the applicable Optional Units Closing Date, as the case may be (and the Representatives shall have received an additional two conformed copies of such accountants’ letter for each of the several Underwriters).

(j) Lock-Up Agreement from Certain Securityholders of the Company. On or prior to the date hereof, the Company shall have furnished to the Representatives an agreement substantially in the form of Exhibit B hereto from each person listed in Exhibit A hereto, and such agreement shall be in full force and effect on each of the Firm Units Closing Date and each Optional Units Closing Date.

(k) Nasdaq Listing. The Company shall have filed a Notification: Listing of Additional Shares with the NASDAQ Global Market and shall have received no objection thereto from the NASDAQ Global Market.

(l) Good Standings. The Representatives shall have received on and as of such Closing Date satisfactory evidence of the good standing of the Company in the State of Delaware and existence as a foreign corporation in the State of Illinois.

(m) Rule 462(b) Registration Statement. In the event that a Rule 462(b) Registration Statement is filed in connection with the offering contemplated by this Agreement, such Rule 462(b) Registration Statement shall have been filed with the Commission on the date of this Agreement and shall have become effective automatically upon such filing.

(n) Additional Documents. On or before each of the Firm Units Closing Date and each Optional Units Closing Date, the Representatives and counsel for the Underwriters

shall have received such information, documents and opinions as they may reasonably request for the purposes of enabling them to pass upon the issuance and sale of the Offered Units as contemplated herein, or in order to evidence the accuracy of any of the representations and warranties, or the satisfaction of any of the conditions or agreements, herein contained; and all proceedings taken by the Company in connection with the issuance and sale of the Offered Units as contemplated herein and in connection with the other transactions contemplated by this Agreement shall be reasonably satisfactory in form and substance to the Representatives and counsel for the Underwriters.

If any condition specified in this Section 6 is not satisfied when and as required to be satisfied, this Agreement may be terminated by the Representatives by notice to the Company at any time on or prior to the Firm Units Closing Date and, with respect to the Optional Shares, at any time on or prior to the applicable Optional Units Closing Date, which termination shall be without liability on the part of any party to any other party, except that Section 4, Section 6, Section 8 and Section 9 shall at all times be effective and shall survive such termination.

Section 7. Reimbursement of Underwriters’ Expenses. If this Agreement is terminated by the Representatives pursuant to Section 6 prior to the Firm Units Closing Date, as a result of the failure of any of the conditions of subsections (a), (b), (c), (d), (e), (g), (h), (i), (j), (k) or (l) of Section 6 to be satisfied when and as required to be satisfied, or Section 12 prior to the Firm Units Closing Date, or if the sale to the Underwriters of the Firm Units on the Firm Units Closing Date is not consummated because of any refusal, inability or failure on the part of the Company to perform any agreement herein or to comply with any provision hereof, the Company agrees to reimburse the Representatives and the other Underwriters (or such Underwriters as have terminated this Agreement with respect to themselves), severally, upon demand for all out-of-pocket expenses that shall have been reasonably incurred by the Representatives and the Underwriters in connection with the proposed purchase and the offering and sale of the Offered Units, including but not limited to fees and disbursements of counsel, printing expenses, travel expenses, postage, facsimile and telephone charges.

Section 8. Effectiveness of this Agreement. This Agreement shall become effective upon the execution of this Agreement by the parties hereto.

Section 9. Indemnification.

(a) Indemnification of the Underwriters. The Company agrees to indemnify and hold harmless each Underwriter, its officers and employees, and each person, if any, who controls any Underwriter within the meaning of the Securities Act or the Exchange Act against any loss, claim, damage, liability or expense, as incurred, to which such Underwriter or such officer, employee or controlling person may become subject, under the Securities Act, the Exchange Act, other federal or state statutory law or regulation, or the laws or regulations of foreign jurisdictions where Offered Units have been offered or sold or at common law or otherwise (including in settlement of any litigation, if such settlement is effected in accordance with Section 9(d) below), insofar as such loss, claim, damage, liability or expense (or actions in respect thereof as contemplated below) arises out of or is based upon (i) any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement, or any amendment thereto, including any information deemed to be a part thereof pursuant to Rule 430A under the Securities Act, or the omission or alleged omission therefrom of a material fact required to be stated therein or necessary to make the statements therein not misleading; or (ii) any untrue statement or alleged untrue statement of a material fact contained in any preliminary prospectus, the Time of Sale Prospectus, any free writing prospectus that the Company has used, referred to

or filed, or is required to file, pursuant to Rule 433(d) of the Securities Act or the Prospectus (or any amendment or supplement thereto), or the omission or alleged omission therefrom of a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; and to reimburse each such Underwriter and each such officer, employee and controlling person for any and all expenses (including the fees and disbursements of counsel chosen by Cowen, JMP and Stifel) as such expenses are reasonably incurred by such Underwriter or such officer, employee or controlling person in connection with investigating, defending, settling, compromising or paying any such loss, claim, damage, liability, expense or action; provided, however, that the foregoing indemnity agreement shall not apply to any loss, claim, damage, liability or expense to the extent, but only to the extent, arising out of or based upon any untrue statement or alleged untrue statement or omission or alleged omission made in reliance upon and in conformity with written information furnished to the Company by the Representatives expressly for use in the Registration Statement, any preliminary prospectus, the Time of Sale Prospectus, any such free writing prospectus or the Prospectus (or any amendment or supplement thereto), it being understood and agreed that the only such information furnished by the Representatives to the Company consists of the information described in subsection (b) below. The indemnity agreement set forth in this Section 9(a) shall be in addition to any liabilities that the Company may otherwise have.

(b) Indemnification of the Company, its Directors and Officers. Each Underwriter agrees, severally and not jointly, to indemnify and hold harmless the Company, each of its directors and officers and each person, if any, who controls the Company within the meaning of the Securities Act or the Exchange Act, against any loss, claim, damage, liability or expense, as incurred, to which the Company, or any such director, officer or controlling person may become subject, under the Securities Act, the Exchange Act, or other federal or state statutory law or regulation, or at common law or otherwise (including in settlement of any litigation, if such settlement is effected with the written consent of such Underwriter), insofar as such loss, claim, damage, liability or expense (or actions in respect thereof as contemplated below) arises out of or is based upon any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement, any preliminary prospectus, the Time of Sale Prospectus, any free writing prospectus that the Company has used, referred to or filed, or is required to file, pursuant to Rule 433(d) of the Securities Act or the Prospectus (or such amendment or supplement thereto), or arises out of or is based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, in each case to the extent, but only to the extent, that such untrue statement or alleged untrue statement or omission or alleged omission was made in the Registration Statement, such preliminary prospectus, the Time of Sale Prospectus, such free writing prospectus that the Company has used, referred to or filed, or is required to file, pursuant to Rule 433(d) of the Securities Act, the Prospectus (or such amendment or supplement thereto), in reliance upon and in conformity with written information furnished to the Company by the Representatives expressly for use therein; and to reimburse the Company, or any such director, officer or controlling person for any legal and other expense as such expenses are reasonably incurred by the Company, or any such director, officer or controlling person in connection with investigating, defending, settling, compromising or paying any such loss, claim, damage, liability, expense or action. The Company hereby acknowledges that the only information that the Representatives and the Underwriters have furnished to the Company expressly for use in the Registration Statement, any preliminary prospectus, the Time of Sale Prospectus, any free writing prospectus that the Company has filed, or is required to file, pursuant to Rule 433(d) of the Securities Act or the Prospectus (or any amendment or supplement thereto) are the statements set forth in the first two sentences and the last sentence of the first paragraph under the section entitled “Commissions and Expenses” and the second, third, fourth and fifth paragraphs under the

section entitled “Price Stabilization, Short Positions and Penalty Bids”, each under the caption “Underwriting” in the Company’s Preliminary Prospectus and the Prospectus relating to the offering of the Offered Units. The indemnity agreement set forth in this Section 9(b) shall be in addition to any liabilities that each Underwriter may otherwise have.

(c) Notifications and Other Indemnification Procedures. Promptly after receipt by an indemnified party under this Section 9 of notice of the commencement of any action, such indemnified party will, if a claim in respect thereof is to be made against an indemnifying party under this Section 9, notify the indemnifying party in writing of the commencement thereof, but the failure to so notify the indemnifying party will not relieve such indemnifying party from any liability which it may have to any indemnified party for contribution or otherwise under the indemnity agreement contained in this Section 9 except to the extent such indemnifying party has been materially prejudiced by such failure. In case any such action is brought against any indemnified party and such indemnified party seeks or intends to seek indemnity from an indemnifying party, the indemnifying party will be entitled to participate in, and, to the extent that it shall elect, jointly with all other indemnifying parties similarly notified, by written notice delivered to the indemnified party promptly after receiving the aforesaid notice from such indemnified party, to assume the defense thereof with counsel reasonably satisfactory to such indemnified party; provided, however, if the defendants in any such action include both the indemnified party and the indemnifying party and the indemnified party shall have reasonably concluded that a conflict may arise between the positions of the indemnifying party and the indemnified party in conducting the defense of any such action or that there may be legal defenses available to it and/or other indemnified parties which are different from or additional to those available to the indemnifying party, the indemnified party or parties shall have the right to select separate counsel to assume such legal defenses and to otherwise participate in the defense of such action on behalf of such indemnified party or parties. Upon receipt of notice from the indemnifying party to such indemnified party of such indemnifying party’s election so to assume the defense of such action and approval by the indemnified party of counsel, the indemnifying party will not be liable to such indemnified party under this Section 9 for any legal or other expenses subsequently incurred by such indemnified party in connection with the defense thereof unless (i) the indemnified party shall have employed separate counsel in accordance with the proviso to the preceding sentence (it being understood, however, that the indemnifying party shall not be liable for the fees and expenses of more than one separate counsel (together with local counsel), representing the indemnified parties who are parties to such action), which counsel (together with any local counsel) for the indemnified parties shall be selected by Stifel, Cowen and JMP (in the case of counsel for the indemnified parties referred to in Section 9(a) above) or by the Company (in the case of counsel for the indemnified parties referred to in Section 9(b) above)) (ii) the indemnifying party shall not have employed counsel reasonably satisfactory to the indemnified party to represent the indemnified party within a reasonable time after notice of commencement of the action or (iii) the indemnifying party has authorized in writing the employment of counsel for the indemnified party at the expense of the indemnifying party, in each of which cases the fees and expenses of counsel shall be at the expense of the indemnifying party and shall be paid as they are incurred.

(d) Settlements. The indemnifying party under this Section 9 shall not be liable for any settlement of any proceeding effected without its written consent, but if settled with such consent or if there be a final judgment for the plaintiff, the indemnifying party agrees to indemnify the indemnified party against any loss, claim, damage, liability or expense by reason of such settlement or judgment. Notwithstanding the foregoing sentence, if at any time an indemnified party shall have requested an indemnifying party to reimburse the indemnified party for fees and expenses of counsel as contemplated by Section 9(c) hereof, the indemnifying party

agrees that it shall be liable for any settlement of any proceeding effected without its written consent if (i) such settlement is entered into more than 60 days after receipt by such indemnifying party of the aforesaid request and (ii) such indemnifying party shall not have reimbursed the indemnified party in accordance with such request prior to the date of such settlement. No indemnifying party shall, without the prior written consent of the indemnified party, effect any settlement, compromise or consent to the entry of judgment in any pending or threatened action, suit or proceeding in respect of which any indemnified party is or could have been a party and indemnity was or could have been sought hereunder by such indemnified party, unless such settlement, compromise or consent includes an unconditional release of such indemnified party from all liability on claims that are the subject matter of such action, suit or proceeding.

Section 10. Contribution. If the indemnification provided for in Section 9 is for any reason held to be unavailable to or otherwise insufficient to hold harmless an indemnified party in respect of any losses, claims, damages, liabilities or expenses referred to therein, then each indemnifying party shall contribute to the aggregate amount paid or payable by such indemnified party, as incurred, as a result of any losses, claims, damages, liabilities or expenses referred to therein (i) in such proportion as is appropriate to reflect the relative benefits received by the Company, on the one hand, and the Underwriters, on the other hand, from the offering of the Offered Units pursuant to this Agreement or (ii) if the allocation provided by clause (i) above is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause (i) above but also the relative fault of the Company, on the one hand, and the Underwriters, on the other hand, in connection with the statements or omissions which resulted in such losses, claims, damages, liabilities or expenses, as well as any other relevant equitable considerations. The relative benefits received by the Company, on the one hand, and the Underwriters, on the other hand, in connection with the offering of the Offered Units pursuant to this Agreement shall be deemed to be in the same respective proportions as the total net proceeds from the offering of the Offered Units pursuant to this Agreement (before deducting expenses) received by the Company, and the total underwriting discounts and commissions received by the Underwriters, in each case as set forth on the front cover page of the Prospectus bear to the aggregate initial public offering price of the Offered Units as set forth on such cover. The relative fault of the Company, on the one hand, and the Underwriters, on the other hand, shall be determined by reference to, among other things, whether any such untrue or alleged untrue statement of a material fact or omission or alleged omission to state a material fact relates to information supplied by the Company, on the one hand, or the Underwriters, on the other hand, and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.

The amount paid or payable by a party as a result of the losses, claims, damages, liabilities and expenses referred to above shall be deemed to include, subject to the limitations set forth in Section 9(c), any legal or other fees or expenses reasonably incurred by such party in connection with investigating or defending any action or claim. The provisions set forth in Section 9(c) with respect to notice of commencement of any action shall apply if a claim for contribution is to be made under this Section 10; provided, however, that no additional notice shall be required with respect to any action for which notice has been given under Section 9(c) for purposes of indemnification.

The Company and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 10 were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation which does not take account of the equitable considerations referred to in this Section 10.

Notwithstanding the provisions of this Section 10, no Underwriter shall be required to contribute any amount in excess of the underwriting discounts and commissions received by such Underwriter in connection with the Offered Units underwritten by it and distributed to the public. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Underwriters’ obligations to contribute pursuant to this Section 10 are several, and not joint, in proportion to their respective underwriting commitments as set forth opposite their respective names on Schedule A. For purposes of this Section 10, each officer and employee of an Underwriter and each person, if any, who controls an Underwriter within the meaning of the Securities Act or the Exchange Act shall have the same rights to contribution as such Underwriter, and each director of the Company, each officer of the Company, and each person, if any, who controls the Company with the meaning of the Securities Act and the Exchange Act shall have the same rights to contribution as the Company.

Section 11. Default of One or More of the Several Underwriters. If, on the Firm Units Closing Date or the applicable Optional Units Closing Date, as the case may be, any one or more of the several Underwriters shall fail or refuse to purchase Offered Units that it or they have agreed to purchase hereunder on such date, and the aggregate number of Offered Units which such defaulting Underwriter or Underwriters agreed but failed or refused to purchase does not exceed 10% of the aggregate number of the Offered Units required to be purchased on such date by the Underwriters, the Representatives may make arrangements satisfactory to the Company for the purchase of such Offered Units by other persons, including any of the Underwriters, but if no such arrangements are made by such Closing Date, the other Underwriters shall be obligated, severally and not jointly, in the proportions that the number of Offered Units set forth opposite their respective names on Schedule A bears to the aggregate number of Offered Units set forth opposite the names of all such non-defaulting Underwriters, or in such other proportions as may be specified by the Representatives with the consent of the non-defaulting Underwriters, to purchase the Offered Units which such defaulting Underwriter or Underwriters agreed but failed or refused to purchase on such date. If, on the Firm Units Closing Date or the applicable Optional Units Closing Date, as the case may be, any one or more of the Underwriters shall fail or refuse to purchase Offered Units and the aggregate number of Offered Units with respect to which such default occurs exceeds 10% of the aggregate number of Offered Units required to be purchased on such date by the Underwriters, and arrangements satisfactory to the Representatives and the Company for the purchase of such Offered Units are not made within 48 hours after such default, this Agreement shall terminate without liability of any non-defaulting party to any other party (provided that if such default occurs with respect to Optional Units after the Firm Units Closing Date, this Agreement will not terminate as to the Firm Units or any Optional Units purchased prior to such termination) except that the provisions of Section 4, Section 9 and Section 10 shall at all times be effective and shall survive such termination. In any such case either the Representatives or the Company shall have the right to postpone the Firm Units Closing Date or the applicable Optional Units Closing Date, as the case may be, but in no event for longer than seven days in order that the required changes, if any, to the Registration Statement and the Prospectus or any other documents or arrangements may be effected.

As used in this Agreement, the term “Underwriter” shall be deemed to include any person substituted for a defaulting Underwriter under this Section 11. Any action taken under this Section 11 shall not relieve any defaulting Underwriter from liability in respect of any default of such Underwriter under this Agreement.

Section 12. Termination of this Agreement. Prior to the purchase of the Firm Units by the Underwriters on the Firm Units Closing Date this Agreement may be terminated by

the Representatives by notice given to the Company if at any time (i) trading or quotation in any of the Company’s securities shall have been suspended or materially limited by the Commission or by the Nasdaq Global Market, or trading in securities generally on either the Nasdaq Stock Market or the New York Stock Exchange shall have been suspended or materially limited, or minimum or maximum prices shall have been generally established on any of such stock exchanges by the Commission or FINRA; (ii) a general banking moratorium shall have been declared by any of federal, New York, Delaware or California authorities or a material disruption has occurred in commercial banking or securities settlement or clearance services in the United States; (iii) there shall have occurred any outbreak or escalation of national or international hostilities or any crisis or calamity, or any change in the United States or international financial markets, or any substantial change or development involving a prospective substantial change in United States’ or international political, financial or economic conditions, as in the judgment of the Representatives is material and adverse and makes it impracticable to market the Offered Units in the manner and on the terms described in the Time of Sale Prospectus or the Prospectus or to enforce contracts for the sale of securities; or (iv) in the judgment of the Representatives there shall have occurred any Material Adverse Change. Any termination pursuant to this Section 12 shall be without liability on the part of (A) the Company to any Underwriter, except that the Company shall be obligated to reimburse the expenses of the Representatives and the Underwriters pursuant to Sections 4 and 7 hereof, (B) any Underwriter to the Company, or (c) of any party hereto to any other party except that the provisions of Section 9 and Section 10 shall at all times be effective and shall survive such termination.

Section 13. No Advisory or Fiduciary Relationship. The Company acknowledges and agrees that (a) the purchase and sale of the Offered Units pursuant to this Agreement, including the determination of the public offering price of the Offered Units and any related discounts and commissions, is an arm’s-length commercial transaction between the Company, on the one hand, and the several Underwriters, on the other hand, (b) in connection with the offering contemplated hereby and the process leading to such transaction each Underwriter is and has been acting solely as a principal and is not the agent or fiduciary of the Company, or its stockholders, creditors, employees or any other party, (c) no Underwriter has assumed or will assume an advisory or fiduciary responsibility in favor of the Company with respect to the offering contemplated hereby or the process leading thereto (irrespective of whether such Underwriter has advised or is currently advising the Company on other matters) and no Underwriter has any obligation to the Company with respect to the offering contemplated hereby except the obligations expressly set forth in this Agreement, (d) the Underwriters and their respective affiliates may be engaged in a broad range of transactions that involve interests that differ from those of the Company, and (e) the Underwriters have not provided any legal, accounting, regulatory or tax advice with respect to the offering contemplated hereby and the Company has consulted its own legal, accounting, regulatory and tax advisors to the extent it deemed appropriate

Section 14. Representations and Indemnities to Survive Delivery. The respective indemnities, agreements, representations, warranties and other statements of the Company, of its officers and of the several Underwriters set forth in or made pursuant to this Agreement will remain in full force and effect, regardless of any investigation made by or on behalf of any Underwriter or the Company or any of its or their partners, officers or directors or any controlling person, as the case may be, and, anything herein to the contrary notwithstanding, will survive delivery of and payment for the Offered Units sold hereunder and any termination of this Agreement.

Section 15. Notices. All communications hereunder shall be in writing and shall be mailed, hand delivered or telecopied and confirmed to the parties hereto as follows:

If to the Representatives:

▇▇▇▇▇ and Company, LLC

▇▇▇ ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇

▇▇▇ ▇▇▇▇, ▇▇ ▇▇▇▇▇

Facsimile: (▇▇▇) ▇▇▇-▇▇▇▇

Attention: General Counsel

and

JMP Securities LLC

▇▇▇ ▇▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇▇▇ ▇▇▇▇

▇▇▇ ▇▇▇▇▇▇▇▇▇, ▇▇ ▇▇▇▇▇

Facsimile: (▇▇▇) ▇▇▇-▇▇▇▇

Attention: General Counsel

and

▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated

▇▇▇ ▇▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇▇▇ ▇▇▇▇

▇▇▇ ▇▇▇▇▇▇▇▇▇, ▇▇ ▇▇▇▇▇

Facsimile: (▇▇▇) ▇▇▇-▇▇▇▇

Attention: General Counsel

with a copy (which shall not constitute notice hereunder) to :

▇▇▇▇▇▇▇ Procter LLP

The New York Times Building

▇▇▇ ▇▇▇▇▇▇ ▇▇▇▇▇▇

▇▇▇ ▇▇▇▇, ▇▇ ▇▇▇▇▇

Facsimile: (▇▇▇) ▇▇▇-▇▇▇▇

Attention: ▇▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇, Esq.

If to the Company:

Horizon Pharma, Inc.

▇▇▇ ▇▇▇▇ ▇▇▇▇ ▇▇▇▇, ▇▇▇▇▇ ▇▇▇

▇▇▇▇▇▇▇▇▇, ▇▇ ▇▇▇▇▇

Facsimile: (▇▇▇) ▇▇▇-▇▇▇▇

Attention: ▇▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇

with a copy (which shall not constitute notice hereunder) to:

▇▇▇▇▇▇ LLP

▇▇▇▇ ▇▇▇▇▇▇▇▇ ▇▇▇▇

▇▇▇ ▇▇▇▇▇, ▇▇ ▇▇▇▇▇

Facsimile: (▇▇▇) ▇▇▇-▇▇▇▇

Attention: L. ▇▇▇ ▇▇▇▇▇▇▇▇, Esq.

Any party hereto may change the address for receipt of communications by giving written notice to the others.

Section 16. Successors. This Agreement will inure to the benefit of and be binding upon the parties hereto, including any substitute Underwriters pursuant to Section 11 hereof, and to the benefit of the employees, officers and directors and controlling persons referred to in Section 9 and Section 10, and in each case their respective successors, and no other person will have any right or obligation hereunder. The term “successors” shall not include any purchaser of the Offered Units as such from any of the Underwriters merely by reason of such purchase.

Section 17. Partial Unenforceability. The invalidity or unenforceability of any Section, paragraph or provision of this Agreement shall not affect the validity or enforceability of any other Section, paragraph or provision hereof. If any Section, paragraph or provision of this Agreement is for any reason determined to be invalid or unenforceable, there shall be deemed to be made such minor changes (and only such minor changes) as are necessary to make it valid and enforceable.

Section 18. Governing Law Provisions. This Agreement shall be governed by and construed in accordance with the internal laws of the State of New York applicable to agreements made and to be performed in such state. Any legal suit, action or proceeding arising out of or based upon this Agreement or the transactions contemplated hereby (“Related Proceedings”) may be instituted in the federal courts of the United States of America located in the Borough of Manhattan in the City of New York or the courts of the State of New York in each case located in the Borough of Manhattan in the City of New York (collectively, the “Specified Courts”), and each party irrevocably submits to the exclusive jurisdiction (except for proceedings instituted in regard to the enforcement of a judgment of any such court (a “Related Judgment”), as to which such jurisdiction is non-exclusive) of such courts in any such suit, action or proceeding. Service of any process, summons, notice or document by mail to such party’s address set forth above shall be effective service of process for any suit, action or other proceeding brought in any such court. The parties irrevocably and unconditionally waive any objection to the laying of venue of any suit, action or other proceeding in the Specified Courts and irrevocably and unconditionally waive and agree not to plead or claim in any such court that any such suit, action or other proceeding brought in any such court has been brought in an inconvenient forum.

With respect to any Related Proceeding, each party irrevocably waives, to the fullest extent permitted by applicable law, all immunity (whether on the basis of sovereignty or otherwise) from jurisdiction, service of process, attachment (both before and after judgment) and execution to which it might otherwise be entitled in the Specified Courts, and with respect to any Related Judgment, each party waives any such immunity in the Specified Courts or any other court of competent jurisdiction, and will not raise or claim or cause to be pleaded any such immunity at or in respect of any such Related Proceeding or Related Judgment, including, without limitation, any immunity pursuant to the United States Foreign Sovereign Immunities Act of 1976, as amended.

Section 19. General Provisions. This Agreement constitutes the entire agreement of the parties to this Agreement and supersedes all prior written or oral and all contemporaneous oral agreements, understandings and negotiations with respect to the subject matter hereof. This Agreement may be executed in two or more counterparts, each one of which shall be an original, with the same effect as if the signatures thereto and hereto were upon the same instrument. This Agreement may not be amended or modified unless in writing by all of the parties hereto, and no condition herein (express or implied) may be waived unless waived in writing by each party

whom the condition is meant to benefit. The Table of Contents and the Section headings herein are for the convenience of the parties only and shall not affect the construction or interpretation of this Agreement.

Each of the parties hereto acknowledges that it is a sophisticated business person who was adequately represented by counsel during negotiations regarding the provisions hereof, including, without limitation, the indemnification provisions of Section 9 and the contribution provisions of Section 10, and is fully informed regarding said provisions. Each of the parties hereto further acknowledges that the provisions of Sections 9 and 10 hereto fairly allocate the risks in light of the ability of the parties to investigate the Company, its affairs and its business in order to assure that adequate disclosure has been made in the Registration Statement, any preliminary prospectus, the Time of Sale Prospectus, each free writing prospectus and the Prospectus (and any amendments and supplements thereto), as required by the Securities Act and the Exchange Act.

[Signature page follows]

If the foregoing is in accordance with your understanding of our agreement, kindly sign and return to the Company the enclosed copies hereof, whereupon this instrument, along with all counterparts hereof, shall become a binding agreement in accordance with its terms.


Very truly yours,

HORIZON PHARMA, INC.

By:		/s/ ▇▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇
		▇▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇
		Chief Executive Officer

The foregoing Underwriting Agreement is hereby confirmed and accepted by the Representatives in New York, New York as of the date first above written.


▇▇▇▇▇ AND COMPANY, LLC JMP SECURITIES LLC
▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & COMPANY, INCORPORATED
Acting as Representatives of the several Underwriters named in the attached Schedule A.

By:	▇▇▇▇▇ AND COMPANY, LLC

	By:	/s/ ▇▇▇▇▇ ▇▇▇▇▇▇
		Managing Director

By:	JMP SECURITIES LLC

	By:	/s/ ▇▇▇▇▇▇ ▇▇▇▇▇
		Managing Director

By:	▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & COMPANY, INCORPORATED

	By:	/s/ ▇▇▇▇▇ ▇▇▇▇▇▇
		Managing Director

SCHEDULE A


Underwriters	Number of Firm Units to be Purchased
▇▇▇▇▇ and Company, LLC		8,570,000

JMP Securities LLC		8,570,000

▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated		4,285,000

Total		21,425,000

Schedule A-1

SCHEDULE B

Schedule of Free Writing Prospectuses included in the Time of Sale Prospectus

None

Schedule B-1

SCHEDULE C

Schedule of Pricing Information Included in the Time of Sale Prospectus

Size: 21,425,000 Units

Overallotment option: 3,213,750 Optional Shares and/or 3,213,750 Optional Warrants

Public offering: $3.49 per Share and $0.01 per Warrant

Net proceeds (excluding overallotment option): $70,488,250 million

Schedule C-1

EXHIBIT A

List of Persons Executing Lock-Ups

Directors

▇▇▇▇▇▇▇ ▇. ▇▇▇▇

▇▇▇▇-▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇

▇▇▇▇▇▇▇ ▇▇▇▇

▇▇▇▇ ▇▇▇▇▇▇▇

▇▇▇▇▇▇ ▇▇▇▇▇

▇▇▇▇ ▇▇▇▇▇▇▇

Officers

▇▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇

▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇

▇▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇

▇▇▇▇▇▇▇ ▇▇▇▇▇▇

▇▇▇▇ ▇. ▇▇▇▇▇

Exhibit A-1

EXHIBIT B

Form of Lock Up Agreement

, 2012

▇▇▇▇▇ and Company, LLC

▇▇▇ ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇

▇▇▇ ▇▇▇▇, ▇▇ ▇▇▇▇▇

JMP Securities LLC

▇▇▇ ▇▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇▇▇ ▇▇▇▇

▇▇▇ ▇▇▇▇▇▇▇▇▇, ▇▇ ▇▇▇▇▇

▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated

▇▇▇ ▇▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇▇▇ ▇▇▇▇

▇▇▇ ▇▇▇▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇

As Representatives of the several Underwriters

Re: Horizon Pharma, Inc.

Dear Sirs:

This lock-up agreement (the “Agreement”) is being delivered to you in connection with the proposed Underwriting Agreement (the “Underwriting Agreement”) between Horizon Pharma, Inc., a Delaware corporation (the “Company”) and ▇▇▇▇▇ and Company, LLC (“Cowen”), JMP Securities LLC (“JMP”) and ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel” and, together with Cowen and JMP, the “Representatives”) as representatives of a group of underwriters to be named therein (collectively, the “Underwriters”), relating to the proposed public offering (the “Offering”) of shares of the common stock, par value $0.0001 per share (the “Common Stock”), of the Company.

In order to induce you to enter into the Underwriting Agreement, and in light of the benefits that the Offering of the Common Stock will confer upon the undersigned in his or her capacity as a security holder and/or an officer, director or employee of the Company, and for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the undersigned agrees with the Representatives that, during the period beginning on and including the date of the Underwriting Agreement through and including the date that is the 90^th day after the date of the Underwriting Agreement (the “Lock-Up Period”), the undersigned will not, without the prior written consent of the Representatives, directly or indirectly, (i) offer, sell, assign, transfer, pledge, contract to sell, or otherwise dispose of, or publicly announce the intention to otherwise dispose of, any Common Stock (including, without limitation, Common Stock which may be deemed to be beneficially owned by the undersigned in accordance with the rules and regulations promulgated under the Securities Act of 1933, as amended (the “Securities Act”) (such shares, the “Beneficially Owned Shares”)) or securities convertible into or exercisable or exchangeable for Common Stock; (ii) enter into any swap, hedge or similar agreement or arrangement that transfers in whole or in part, the economic risk of ownership of the Beneficially Owned Shares or securities convertible into or exercisable or exchangeable for Common Stock, whether now owned or hereafter acquired by the undersigned or with respect to

Exhibit B-1

which the undersigned has or hereafter acquires the power of disposition, or (iii) engage in any short selling of the Common Stock or securities convertible into or exercisable or exchangeable for Common Stock. To the extent you are at such time providing research coverage to the Company and subject to the restrictions set forth in FINRA Rule 2711(f)(4), then if (i) the Company issues an earnings release or material news or a material event relating to the Company occurs during the last 17 days of the Lock-Up Period, or (ii) prior to the expiration of the Lock-Up Period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the Lock-Up Period, then in each case the Lock-Up Period shall be extended and the restrictions imposed by this Agreement shall continue to apply until the expiration of the 18-day period beginning on the date of the issuance of the earnings release or the occurrence of the material news or material event except that such extension will not apply if, (x) the Common Stock is an “actively traded security” (as defined in Regulation M under the Securities Exchange Act of 1934, as amended (the “Exchange Act”)), (y) the Company meets the applicable requirements of Rule 139(a)(1) under the Securities Act in the manner contemplated by NASD Conduct Rule 2711(f)(4) and (z) the provisions of NASD Conduct Rule 2711(f)(4) do not restrict the publication or distribution, by any Underwriter, of any research reports relating to the Company during the 15 days before or after the last day of the Lock-Up Period (before giving effect to such extension).

The restrictions set forth in the immediately preceding paragraph shall not apply to any transfers made by the undersigned (i) as a bona fide gift to any member of the immediate family (as defined below) of the undersigned or to a trust the beneficiaries of which are exclusively the undersigned or members of the undersigned’s immediate family, (ii) by will or intestate succession upon the death of the undersigned, (iii) as forfeitures or sales of Common Stock to satisfy tax withholding obligations of the undersigned in connection with the vesting, settlement or exercise of equity awards by the undersigned pursuant to the Company’s equity plans, (iv) pursuant to a net exercise or cashless exercise by the undersigned of outstanding equity awards pursuant to the Company’s equity plans; provided that that any Common Stock acquired upon the net exercise or cashless exercise of equity awards described in this clause (iv) above shall be subject to the restrictions set forth in the immediately preceding paragraph, (v) pursuant to the conversion or sale of, or an offer to purchase, all or substantially all of the outstanding Common Stock, whether pursuant to a merger, tender offer or otherwise, or (vi) as a bona fide gift to a charity or educational institution; provided, however, that in the case of any transfer described in clauses (i) and (ii) above, it shall be a condition to the transfer that (A) the transferee executes and delivers to Cowen, not later than one business day prior to such transfer, a written agreement, in substantially the form of this Agreement (it being understood that any references to “immediate family” in the agreement executed by such transferee shall expressly refer only to the immediate family of the undersigned and not to the immediate family of the transferee) and otherwise reasonably satisfactory in form and substance to Cowen, and (B) if the undersigned is required to file a report under Section 16(a) of the Securities Exchange Act reporting a reduction in beneficial ownership of Common Stock or Beneficially Owned Shares or any securities convertible into or exercisable or exchangeable for Common Stock or Beneficially Owned Shares during the Lock-Up Period (as the same may be extended as described above), the undersigned shall include a statement in such report to the effect that such transfer is being made as a gift or by will or intestate succession, as applicable. In addition, in the case of any transfer described in clauses (iii) and (iv) above, it shall be a condition to the transfer that if the undersigned is required to file a report under Section 16(a) of the Securities Exchange Act reporting a reduction in beneficial ownership of Common Stock or Beneficially Owned Shares or any securities convertible into or exercisable or exchangeable for Common Stock or Beneficially Owned Shares during the Lock-Up Period (as the same may be extended as described above), the undersigned shall include a statement in such report to the effect that such transfer is being made for tax

Exhibit B-2

withholding obligations or for net exercise or cashless exercise purposes, as applicable. For purposes of this paragraph, “immediate family” shall mean a spouse, child, grandchild or other lineal descendant (including by adoption), father, father-in-law, mother, mother-in-law, brother or sister of the undersigned.

After the date of this Agreement, the undersigned may at any time enter into a written plan meeting the requirements of Rule 10b5-1 under the Securities Exchange Act relating to the sale of Common Stock or Beneficially Owned Shares, if then permitted by the Company; provided that the shares subject to such plan shall be subject to the restrictions set forth in this Agreement during the Lock-Up Period.

In order to enable this covenant to be enforced, the undersigned hereby consents to the placing of legends or stop transfer instructions with the Company’s transfer agent with respect to any Common Stock or securities convertible into or exercisable or exchangeable for Common Stock.

The undersigned further agrees that it will not, during the Lock-Up Period (as the same may be extended as described above), make any demand or request for or exercise any right with respect to the registration under the Securities Act of any Common Stock or other Beneficially Owned Shares or any securities convertible into or exercisable or exchangeable for Common Stock or other Beneficially Owned Shares.

The undersigned hereby represents and warrants that the undersigned has full power and authority to enter into this Agreement and that this Agreement has been duly authorized (if the undersigned is not a natural person), executed and delivered by the undersigned and is a valid and binding agreement of the undersigned. This Agreement and all authority herein conferred are irrevocable and shall survive the death or incapacity of the undersigned (if a natural person) and shall be binding upon the undersigned and upon the heirs, personal representatives, successors and assigns of the undersigned.

It is understood and agreed that if (i) the Underwriting Agreement is not executed by October 31, 2012, (ii) the Company notifies you in writing that it does not intend to proceed with the offering of Common Stock, (iii) the undersigned ceases to serve as an officer or director of the Company, or (iv) the Underwriting Agreement shall be terminated (other than the provisions that survive termination thereof) prior to payment for and delivery of the securities to be sold pursuant thereto, the undersigned shall be released from his or her obligations under the provisions of this Agreement.

[Remainder of page intentionally left blank]

Exhibit B-3

This Agreement shall be governed by, and construed in accordance with, the laws of the State of New York.

Very truly yours,

(Name - Please Print)

(Signature)

(Name of Signatory if an entity - Please Print)

(Title of Signatory if an entity - Please Print)


Address:


By:
		Signature


Printed Name of Person Signing

(and indicate capacity of person signing if

signing as custodian, trustee, or on behalf of an entity)

Exhibit B-4

21,425,000 Units Each Unit Consisting of One Share of Common Stock ($0.0001 par value per Share) And A Warrant to Purchase 0.50 of a Share of Common Stock HORIZON PHARMA, INC. UNDERWRITING AGREEMENT

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