Exhibit 1.1

Convio, Inc.

Common Stock, Par Value $0.001

Underwriting Agreement

Ladies and Gentlemen:

Convio, Inc., a Delaware Corporation (“Company”), proposes, subject to the terms and conditions stated herein, to issue and sell to the Underwriters named in Schedule I hereto (the “Underwriters”) an aggregate of [        ] shares of Common Stock, par value $0.001 per share (“Stock”) of the Company, and, at the election of the Underwriters, up to [        ] additional shares of Stock, and the stockholders of the Company named in Schedule II hereto (the “Selling Stockholders”) propose, subject to the terms and conditions stated herein, severally and not jointly to sell to the Underwriters an aggregate of [        ] shares of Stock.  The aggregate of [        ] shares to be sold by the Company and the Selling Stockholders is herein called the “Firm Shares” and the aggregate of [        ] additional shares to be sold by the Company is herein called the “Optional Shares”.  The Firm Shares and the Optional Shares that the Underwriters elect to purchase pursuant to Section 2 hereof are herein collectively called the “Shares”.

1.             (a)           The Company represents and warrants to, and agrees with, each of the Underwriters that:

(i)           A registration statement on Form S-1 (File No. 333-164491) (the “Initial Registration Statement”) in respect of the Shares has been filed with the Securities and Exchange Commission (the “Commission”); the Initial Registration Statement and any post-effective amendment thereto, each in the form heretofore delivered to you, and, excluding exhibits thereto, to you for each of the other Underwriters, have been declared effective by the Commission in such form; other than a registration statement, if any, increasing the size of the offering (a “Rule 462(b) Registration Statement”), filed pursuant to Rule 462(b) under the Securities Act of 1933, as amended (the “Act”), which became effective upon filing, no other document with respect to the Initial Registration Statement has heretofore been filed with the Commission; and no stop order suspending the effectiveness of the Initial Registration Statement, any post-effective amendment thereto or the Rule 462(b) Registration Statement, if any, has

been issued and no proceeding for that purpose has been initiated or threatened by the Commission (any preliminary prospectus included in the Initial Registration Statement or filed with the Commission pursuant to Rule 424(a) of the rules and regulations of the Commission under the Act is hereinafter called  a “Preliminary Prospectus”;  the various parts of the Initial Registration Statement and the Rule 462(b) Registration Statement, if any, including all exhibits thereto and including the information contained in the form of final prospectus filed with the Commission pursuant to Rule 424(b) under the Act in accordance with Section 6(a) hereof and deemed by virtue of Rule 430A under the Act to be part of the Initial Registration Statement at the time it was declared effective, each as amended at the time such part of the Initial Registration Statement became effective or such part of the Rule 462(b) Registration Statement, if any, became or hereafter becomes effective, are hereinafter collectively called the “Registration Statement”; the Preliminary Prospectus relating to the Shares that was included in the Registration Statement immediately prior to the Applicable Time (as defined in Section 1(a)(iii) hereof) is hereinafter called the “Pricing Prospectus”; such final prospectus, in the form first filed pursuant to Rule 424(b) under the Act, is hereinafter called the  “Prospectus”; and any “issuer free writing prospectus” as defined in Rule 433 under the Act relating to the Shares is hereinafter called an “Issuer Free Writing Prospectus”);

(ii)          No order preventing or suspending the use of any Preliminary Prospectus or any Issuer Free Writing Prospectus has been issued by the Commission, and each Preliminary Prospectus, at the time of filing thereof, conformed in all material respects to the requirements of the Act and the rules and regulations of the Commission thereunder, and did not contain an 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, in the light of the circumstances under which they were made, not misleading; provided, however, that this representation and warranty shall not apply to any statements or omissions made in reliance upon and in conformity with information furnished in writing to the Company by an Underwriter through Thomas Weisel Partners LLC or Piper Jaffray & Co. expressly for use therein;

(iii)         For the purposes of this Agreement, the “Applicable Time” is [        ] p.m. (Eastern time) on the date of this Agreement.  The Pricing Prospectus, as of the Applicable Time, when considered together with the public offering price per Share and the number of Shares offered, each as set forth on the cover page of the Prospectus, did not include any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; and each Issuer Free Writing Prospectus listed on Schedule III hereto does not conflict with the information contained in the Registration Statement, the Pricing Prospectus or the Prospectus and each such Issuer Free Writing Prospectus, as supplemented by and taken together with the Pricing Prospectus as of the Applicable Time, did not include any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided, however, that this representation and warranty shall not apply to statements or omissions made in the Pricing Prospectus or in any Issuer Free Writing Prospectus in reliance upon and in conformity with information furnished in writing to the Company by an Underwriter through Thomas Weisel Partners LLC or Piper Jaffray & Co. expressly for use therein;

(iv)         The Registration Statement conforms, and the Prospectus and any further amendments or supplements to the Registration Statement or the Prospectus will conform, in all material respects to the requirements of the Act and the rules and regulations of the Commission thereunder (the “Rules and Regulations”) and do not and will not, as of the applicable effective date as to each part of the Registration Statement and any amendment thereto and as of the applicable filing date as to the Prospectus and any amendment or supplement thereto, contain an untrue statement of a material

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fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading; provided, however, that this representation and warranty shall not apply to any statements or omissions made in reliance upon and in conformity with information furnished in writing to the Company by an Underwriter through Thomas Weisel Partners LLC or Piper Jaffray & Co. expressly for use therein;

(v)          Neither the Company nor any of its subsidiaries has sustained since the date of the latest audited financial statements included in the Pricing Prospectus any material loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor dispute or court or governmental action, order or decree, otherwise than as set forth or contemplated in the Pricing Prospectus; except for such loss or interference as would not, individually or in the aggregate, have a material adverse effect on the business, prospects, operations, assets, condition (financial or otherwise), stockholders’ equity or results of operations of the Company and its subsidiaries taken as a whole (a “Material Adverse Effect”); and, since the respective dates as of which information is given in the Registration Statement and the Pricing Prospectus, there has not been any change in the capital stock or long-term debt of the Company or any of its subsidiaries, other than the grants of stock options to employees of the Company in the ordinary course of business and the issuance of shares of Stock upon exercise of warrants and stock options by existing stockholders in the ordinary course of business, or any material adverse change, or any development involving a prospective material adverse change, in or affecting the business prospects, operations, assets, condition (financial or otherwise), stockholders’ equity or results of operations of the Company and its subsidiaries taken as a whole, otherwise than as set forth or contemplated in the Pricing Prospectus;

(vi)         The Company and its subsidiaries have good and marketable title to all personal property owned by them, in each case free and clear of all liens, encumbrances and defects except such as are described in the Registration Statement, Pricing Prospectus and Prospectus or such as do not materially affect the value of such property and do not interfere with the use made and proposed to be made of such property by the Company and its subsidiaries; and any real property and buildings held under lease by the Company and its subsidiaries are held by them under valid, subsisting and enforceable leases with such exceptions as are not material and do not interfere with the use made and proposed to be made of such property and buildings by the Company and its subsidiaries and neither the Company nor any subsidiary own any real property;

(vii)        The Company has been duly incorporated and is validly existing as a corporation in good standing under the laws of the state of Delaware, with power and authority (corporate and other) to own its properties and conduct its business as described in the Registration Statement, Pricing Prospectus and Prospectus, and has been duly qualified as a foreign corporation for the transaction of business and is in good standing under the laws of each other jurisdiction in which it owns or leases properties or conducts any business so as to require such qualification, or is subject to no material liability or disability by reason of the failure to be so qualified in any such jurisdiction; and each subsidiary of the Company has been duly incorporated and is validly existing as a corporation in good standing under the laws of its jurisdiction of incorporation;

(viii)       The Company has an authorized capitalization as set forth in the Registration Statement, Pricing Prospectus and Prospectus, and all of the issued shares of capital stock of the Company have been duly and validly authorized and issued, are fully paid and non-assessable and conform to the description of the Stock contained in the Registration Statement, Pricing Prospectus and the Prospectus; and all of the issued shares of capital stock of each subsidiary of the Company have been duly and validly authorized and issued, are fully paid and non-assessable and (except for directors’

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qualifying shares and except as set forth in the Pricing Prospectus) are owned directly or indirectly by the Company, free and clear of all liens, encumbrances, equities or claims; and there are no options, warrants or rights to acquire shares of capital stock of any subsidiary of the Company with respect to stock options (the “Stock Options”) granted pursuant to the stock-based compensation plans of the Company (the “Company Stock Plans”), (a) each grant of a Stock Option was duly authorized no later than the date on which the grant of such Stock Option was by its terms to be effective (the “Grant Date”) by all necessary corporate action, including, as applicable, approval by the board of directors of the Company (or a duly constituted and authorized committee thereof) and any required stockholder approval by the necessary number of votes or written consents, and the award agreement governing such grant (if any) was duly executed and delivered by each party thereto, (b) each such grant was made in accordance with the terms of the Company Stock Plans, and (c) each such grant was properly accounted for in accordance with United States Generally Accepted Accounting Principles;

(ix)         The unissued Shares to be issued and sold by the Company to the Underwriters hereunder have been duly and validly authorized and, when issued and delivered against payment therefor as provided herein, will be duly and validly issued and fully paid and non-assessable and will conform to the description of the Stock contained in the Registration Statement, Pricing Prospectus and Prospectus;

(x)          The issue and sale of the Shares to be sold by the Company and the compliance by the Company with all of the provisions of this Agreement and the consummation of the transactions herein contemplated will not conflict with or result in a breach or violation of any of the terms or provisions of, or constitute a default under, or give rise to a right of termination under any indenture, mortgage, deed of trust, loan agreement or other agreement or instrument to which the Company or any of its subsidiaries is a party or by which the Company or any of its subsidiaries is bound or to which any of the property or assets of the Company or any of its subsidiaries is subject, except for such breaches or violations as would not, individually or in the aggregate, have a Material Adverse Effect, nor will such action result in any violation of the provisions of the Certificate of Incorporation or By-laws of the Company or any statute or any order, rule or regulation of any court or governmental agency or body having jurisdiction over the Company or any of its subsidiaries or any of their properties;

(xi)         No consent, approval, authorization, order, registration, qualification, permit, license, exemption, filing or notice (each an “Authorization”) of, from, with or to any court, tribunal, government, governmental or regulatory authority, self-regulatory organization or body (each, a “Regulatory Body”) is required of the Company for the issue and sale of the Shares or the consummation by the Company of the transactions contemplated by this Agreement, except (A) the registration and the sale of the Shares under the Act; (B) those required by the by-laws, rules and regulations of the Financial Industry Regulatory Authority (“FINRA”) or the NASDAQ Stock Market LLC (“NASDAQ”); (C) those that have already been obtained; (D) such consents, approvals, authorizations, registrations or qualifications as may be required under state securities or Blue Sky laws in connection with the purchase and distribution of the Shares by the Underwriters; and (E) such other Authorizations the absence of which would not, individually or in the aggregate, have a Material Adverse Effect, and, to the Company’s knowledge, no event has occurred that allows or results in, or after notice or lapse of time or both would allow or result in revocation, suspension, termination or invalidation of any such Authorization or any other impairment of the rights of the holder or maker of any such Authorization;

(xii)        All corporate authorizations (including those of stockholders) necessary for the Company to consummate the transactions contemplated in this Agreement have been obtained and are in effect;

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(xiii)       Neither the Company nor any of its subsidiaries is (A) in violation of its certificate of incorporation or by-laws or (B) in default in the performance or observance of any material obligation, agreement, covenant or condition contained in any indenture, mortgage, deed of trust, loan agreement, lease or other agreement or instrument to which it is a party or by which it or any of its properties may be bound, except for such defaults specified under subparagraph (b) herein that would not, individually or in the aggregate, have a Material Adverse Effect;

(xiv)       The statements set forth in the Registration Statement, Pricing Prospectus and Prospectus under the caption “Description of Capital Stock”, insofar as they purport to constitute a summary of the terms of the Stock and under the caption “Underwriting”, insofar as they purport to describe the provisions of the laws and documents referred to therein, are accurate, complete and fair;

(xv)        Other than as set forth in the Registration Statement, Pricing Prospectus and Prospectus, there are no legal or governmental proceedings pending to which the Company or any of its subsidiaries is a party or of which any property of the Company or any of its subsidiaries is the subject which, if determined adversely to the Company or any of its subsidiaries, would, individually or in the aggregate, have a Material Adverse Effect; and, to the best of the Company’s knowledge, no such proceedings are threatened or contemplated by governmental authorities or threatened by others;

(xvi)       The Company is not and, after giving effect to the offering and sale of the Shares and the application of the proceeds thereof, will not be an “investment company”, as such term is defined in the Investment Company Act of 1940, as amended (the “Investment Company Act”);

(xvii)      At the time of filing the Initial Registration Statement, the Company was not and is not an “ineligible issuer,” as defined in Rule 405 under the Act;

(xviii)     Other than as set forth in the Registration Statement, Pricing Prospectus and Prospectus, (a) the Company and its subsidiaries own or possess, or can acquire on reasonable terms, all material rights to patents, licenses, inventions, copyrights, know-how (including trade secrets and other unpatented and/or unpatentable proprietary or confidential information, systems or procedures), trademarks, service marks or trade names (collectively, “Intellectual Property”) currently employed by them in the business now operated by them, and (b) neither the Company nor any of its subsidiaries has received any notice of infringement of or conflict with asserted rights of others with respect to any of the foregoing;

(xix)        No material labor or employment dispute with the employees of the Company or any of its subsidiaries exists or, to the knowledge of the Company, is imminent; and the Company is not aware of any existing, threatened or imminent labor disturbance by the employees of any of its principal suppliers, manufacturers or contractors  and no employees of the Company are subject to a collective bargaining agreement;

(xx)         The Company and its subsidiaries maintain insurance against such losses and risks as is, in the Company’s reasonable judgment, prudent and customary in the businesses in which they are engaged; neither the Company nor any of its subsidiaries has been refused any insurance coverage sought or applied for; and neither the Company nor any of its subsidiaries has any reason to believe that it will not be able to renew its existing insurance coverage as and when such coverage expires or to obtain similar coverage from similar insurers as may be reasonably necessary to continue its business, other than as set forth in the Pricing Prospectus;

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(xxi)         Ernst & Young LLP, who have certified certain financial statements of the Company and its subsidiaries, are independent public accountants as required by the Act and the rules and regulations of the Commission thereunder;

(xxii)        The financial statements of the Company and its subsidiaries (including all notes and schedules thereto) included in the Registration Statement, the Pricing Prospectus and Prospectus present fairly the financial position of the Company and its consolidated subsidiaries at the dates indicated and the statement of operations, stockholders’ equity and cash flows of the Company and its subsidiaries for the periods specified in conformity with generally accepted accounting principles, consistently applied throughout the periods involved, except, with respect to unaudited financials statements, for the omission of footnotes and normal year-end adjustments which are not expected to be material; and the summary and selected financial data included in the Registration Statement, the Pricing Prospectus and the Prospectus presents fairly the information shown therein as at the respective dates and for the respective periods specified and are derived from the consolidated financial statements set forth in the Registration Statement, the Pricing Prospectus and the Prospectus and other financial information;

(xxiii)       The Company maintains a system of internal control over financial reporting (as such term is defined in Rule 13a-15(f) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”)) that complies with the requirements of the Exchange Act 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 generally accepted accounting principles. The Company’s internal control over financial reporting is effective at the reasonable assurance level and the Company is not aware of any material weaknesses in its internal control over financial reporting;

(xxiv)       Since the date of the latest audited financial statements of the Company included in the Pricing 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;

(xxv)        The Company maintains disclosure controls and procedures (as such term is defined in Rule 13a-15(e) under the Exchange Act) that comply with the requirements of the Exchange Act; such disclosure controls and procedures have been designed to ensure that material information relating to the Company and its subsidiaries is made known to the Company’s principal executive officer and principal financial officer by others within those entities; and such disclosure controls and procedures are effective.

(xxvi)       No relationship, direct or indirect, exists between or among the Company, on the one hand, and the directors, officers, stockholders, customers or suppliers of the Company, on the other hand, which is required to be described in the Registration Statement, the Pricing Prospectus and the Prospectus and which is not so described.  There are no outstanding loans, advances or guarantees of indebtedness by the Company to or for the benefit of any of the executive officers or directors of the Company, except as disclosed in the Registration Statement, the Pricing Prospectus and the Prospectus;

(xxvii)      To the knowledge of the Company, no person associated with or acting on behalf of the Company, including without limitation any director, officer, agent or employee of the Company or its subsidiaries has, directly or indirectly, while acting on behalf of the Company or its

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subsidiaries (A) used any corporate funds for unlawful contributions, gifts, entertainment or other unlawful expenses relating to political activity, (B) made any unlawful payment to foreign or domestic government officials or employees or to foreign or domestic political parties or campaigns from corporate funds, (C) violated any provision of the Foreign Corrupt Practices Act of 1977, as amended or (D) made any other unlawful payment;

(xxviii)     Except as contemplated by this Agreement and as disclosed in the Registration Statement, the Pricing Prospectus and the Prospectus, no person is entitled to receive from the Company a brokerage commission, finder’s fee or other like payment in connection with the transactions contemplated herein;

(xxix)       Neither the Company nor any of its subsidiaries or controlled affiliates does business with the government of, or with any person located in any country in a manner that violates in any material respect any of the economic sanctions programs or similar sanctions-related measures of the United States as administered by the United States Treasury Department’s Office of Foreign Assets Control; and the net proceeds from this offering will not be used to fund any operations in, finance any investments in or make any payments to any country, or to make any payments to any person, in a manner that violates any of the economic sanctions of the United States administered by the United States Treasury Department’s Office of Foreign Assets Control;

(xxx)        Neither the Company nor any of its subsidiaries or controlled affiliates does business with the government of Cuba or with any person located in Cuba within the meaning of Section 517.075, Florida Statutes;

(xxxi)       The Company’s board of directors meets the independence requirements of, and has established an audit committee that meets the independence requirements of, the rules and regulations of the Commission and the NASDAQ;

(xxxii)      The Shares issuable upon the exercise of warrants issued by the Company (the “Warrants”) to be exercised by certain of the Selling Stockholders (the “Warrantholders”) have been duly authorized by the Company and validly reserved for issuance, and at the time of delivery to the Underwriters with respect to such Shares, such Shares will be issued and delivered in accordance with the provisions of the applicable Warrant and will be validly issued, fully paid and non-assessable and will conform in all material respects to the descriptions thereof in the Registration Statement, the Pricing Prospectus and the Prospectus; and

(xxxiii)     The Warrants were duly authorized, executed and delivered and constitute valid and binding agreements enforceable against the Company in accordance with their terms except as enforceability may be limited by applicable bankruptcy, insolvency or similar laws affecting creditors’ rights generally or by equitable principles relating to the enforceability; and the Warrants conform in all material respects to the descriptions thereof in the Registration Statement, the Pricing Prospectus and the Prospectus.

(b)           Each of the Selling Stockholders severally and not jointly represents and warrants to, and agrees with, each of the Underwriters and the Company that:

(i)            All consents, approvals, authorizations and orders necessary for the execution and delivery by such Selling Stockholder of this Agreement and the Power of Attorney, in the form heretofore furnished to you (the “Power of Attorney”) and the Custody Agreement in the form heretofore furnished to you (the “Custody Agreement”) or the Irrevocable Notice of Exercise in the form

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heretofore furnished to you (the “Notice”), as the case may be, hereinafter referred to, and for the sale and delivery of the Shares to be sold by such Selling Stockholder hereunder, have been obtained except for (A) the registration and the sale of the Shares under the Act; (B) those required by the by-laws, rules and regulations of the FINRA or the NASDAQ; (C) those that have already been obtained; (D) such consents, approvals, authorizations, registrations or qualifications as may be required under state securities or Blue Sky laws in connection with the purchase and distribution of the Shares by the Underwriters;

(ii)           Such Selling Stockholder has full right, power and authority to enter into this Agreement, the Power of Attorney, and the Custody Agreement or the Notice, as the case may be, and to sell, assign, transfer and deliver the Shares to be sold by such Selling Stockholder hereunder; and with respect to each Selling Stockholder that is an entity, this Agreement, the Power of Attorney and the Custody Agreement or Notice, as the case may be, have each been duly and validly authorized by such Selling Stockholder;

(iii)          The execution, delivery and performance by such Selling Stockholder of this Agreement, the Power of Attorney and the Custody Agreement or Notice, as the case may be, and the consummation of the transactions herein and therein contemplated will (A) not conflict with or result in a breach or violation of any of the terms or provisions of, or constitute a default under, any statute, indenture, mortgage, deed of trust, loan agreement or other agreement or instrument to which such Selling Stockholder is a party or by which such Selling Stockholder is bound or to which any of the property or assets of such Selling Stockholder is subject, (B) if such Selling Stockholder is an entity, result in any violation of the provisions of the charter or by-laws,  the partnership agreement, the trust agreement, or any other organizational and/or governing document, as applicable, of such Selling Stockholder, or (C) result in any violation or breach of any statute or any order, rule or regulation of any court or governmental agency or body having jurisdiction over such Selling Stockholder or the property of such Selling Stockholder, except in the case of clauses (A) and (C) for such conflicts, breaches, defaults or violations that would not reasonably be expected to have a material adverse effect on the ability of the Selling Stockholder to perform its obligations under this Agreement or consummate the transactions contemplated by this Agreement, the Power of Attorney and the Custody Agreement or Notice, as the case may be;

(iv)          Assuming the conversion of the Selling Stockholder’s preferred stock into Stock and the exercise of the Warrants by the Warrantholders, such Selling Stockholder has, and immediately prior to each Time of Delivery (as defined in Section 5 hereof) such Selling Stockholder will have, good and valid title to the Shares to be sold by such Selling Stockholder hereunder, and upon sale and delivery of, and payment of the consideration for the Selling Stockholders’ Shares to be sold by such Selling Stockholder as provided in this Agreement and the crediting of such Selling Stockholders’ Shares to the “security account” or “security accounts” (as defined in Section 8-501(a) of the Uniform Commercial Code of the State of New York (the “UCC”)) of the Underwriters maintained with The Depository Trust Company (“DTC”), each of the Underwriters will become the legal owner of,  and will have good and valid title to, the Selling Stockholders’ Shares purchased by it from such Selling Stockholder, free and clear of all liens, encumbrances, equities or adverse claims; and assuming that none of the Underwriters otherwise has “notice of an adverse claim” (within the meaning of Section 8-105 of the UCC) with respect to such Shares, the Underwriters will each be a “protected purchaser” of such Shares within the meaning of Section 8-303 of the UCC, each of the Underwriters will acquire a “security entitlement” (within the meaning of UCC Section 8-102(a)(17)) to the Shares purchased by such Underwriter from such Selling Stockholder, and no action based on any “adverse claim” (within the

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meaning of UCC Section 8-102(a)(1)) may be successfully asserted against such Underwriter with respect to such Shares;

(v)           Such Selling Stockholder has duly executed and delivered to the Representatives a lock-up agreement (each, a “Lock-Up Agreement”) in the form attached hereto as Annex III;  and with respect to each Selling Stockholder that is an entity, each such Lock-Up Agreement has been duly authorized by such Selling Stockholder

(vi)          Such Selling Stockholder has not taken and will not take, directly or indirectly, any action which is designed to, or that would reasonably be expected to cause or result in stabilization or manipulation of the price of the Stock to facilitate the sale or resale of the Shares;

(vii)         To the extent that any statements or omissions made in the Registration Statement, any Preliminary Prospectus, the Pricing Prospectus, the Prospectus or any amendment or supplement thereto and any Issuer Free Writing Prospectus are made in reliance upon and in conformity with written information furnished to the Company by such Selling Stockholder expressly for use therein in preparation of the disclosures required by Items 7 and 11(m) of Form S-1, (a) such Registration Statement, any Preliminary Prospectus, the Pricing Prospectus, the Prospectus or any amendment or supplement thereto and any Issuer Free Writing Prospectus did not, when they became effective or filed with the Commission, as the case may be, 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 the case of any Preliminary Prospectus, the Pricing Prospectus, the Prospectus, or any amendment or supplement thereto and any Issuer Free Writing Prospectus, in light of the circumstances under which they were made) not misleading, and (b) the Registration Statement, any Preliminary Prospectus, the Pricing Prospectus, the Prospectus or any amendment or supplement thereto and any Issuer Free Writing Prospectus when they became effective or filed with the Commission, as the case may be, conformed and will conform in all material respects to the requirements of the Act and the Rules and Regulations;

(viii)        In order to document the Underwriters’ compliance with the reporting and withholding provisions of the Tax Equity and Fiscal Responsibility Act of 1982 with respect to the transactions herein contemplated, such Selling Stockholder will deliver to you prior to or at the First Time of Delivery (as defined in Section 5) a properly completed and executed United States Treasury Department Form W-9 (or other applicable form or statement specified by Treasury Department regulations in lieu thereof);

(ix)           Certificates in negotiable form representing all of the Shares to be sold by such Selling Stockholder hereunder, other than any Shares to be issued upon exercise of Warrants, have been placed in custody under a Custody Agreement duly executed and delivered by such Selling Stockholder to Computershare Shareholder Services, Inc., as custodian (the “Custodian”), and with respect to any Shares to be issued upon the exercise of the Warrants, such Warrants and a duly completed and executed Notice with respect to all the Shares to be sold by such Selling Stockholder hereunder have been delivered to the Company, and such Selling Stockholder has duly executed and delivered a Power of Attorney, appointing the persons indicated in Schedule II hereto, and each of them, as such Selling Stockholder’s attorneys-in-fact (the “Attorneys-in-Fact”) with authority to execute and deliver this Agreement on behalf of such Selling Stockholder, to determine the purchase price to be paid by the Underwriters to the Selling Stockholders as provided in Section 2 hereof, to authorize the delivery of the Shares to be sold by such Selling Stockholder hereunder, to direct (if applicable) the delivery of Shares to be issued upon exercise of the Warrants and otherwise to act on behalf of such Selling Stockholder in

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connection with the transactions contemplated by this Agreement and the Custody Agreement or the Notice, as the case may be; and

(x)            The Shares represented by the certificates held in custody for such Selling Stockholder under the Custody Agreement or to be issued pursuant to the Notice, as the case may be, are subject to the interests of the Underwriters hereunder; the arrangements made by such Selling Stockholder for such custody, and the appointment by such Selling Stockholder of the Attorneys-in-Fact by the Power of Attorney, are to that extent irrevocable; the obligations of the Selling Stockholders hereunder shall not be terminated (except as provided in this Agreement or in the Custody Agreement or the Power of Attorney), by operation of law, whether by the death or incapacity of any individual Selling Stockholder or, in the case of an estate or trust, by the death or incapacity of any executor or trustee or the termination of such estate or trust, or in the case of a partnership or corporation, by the dissolution of such partnership or corporation, or by the occurrence of any other event; if any individual Selling Stockholder or any such executor or trustee should die or become incapacitated, or if any such estate or trust should be terminated, or if any such partnership or corporation should be dissolved, or if any other such event should occur, before the delivery of the Shares hereunder, certificates representing the Shares shall be delivered by or on behalf of the Selling Stockholders in accordance with the terms and conditions of this Agreement and of the Custody Agreements; and actions taken by the Attorneys-in-Fact pursuant to the Powers of Attorney shall be as valid as if such death, incapacity, termination, dissolution or other event had not occurred, regardless of whether or not the Custodian, the Attorneys-in-Fact, or any of them, shall have received notice of such death, incapacity, termination, dissolution or other event.

(xi)           Such Selling Stockholder is not selling its shares pursuant to this Agreement due to any information concerning the Company which is not set forth in the Registration Statement, the Pricing Prospectus and the Prospectus.

2.             Subject to the terms and conditions herein set forth, (a) the Company and each of the Selling Stockholders, severally and not jointly, agree to sell to each of the Underwriters, and each of the Underwriters agrees, severally and not jointly, to purchase from the Company and each of the Selling Stockholders, at a purchase price per share of $[      ], the number of Firm Shares (to be adjusted by you so as to eliminate fractional shares) determined by multiplying the aggregate number of Firm Shares to be sold by the Company and each of the Selling Stockholders as set forth opposite their respective names in Schedule II hereto by a fraction, the numerator of which is the aggregate number of Firm Shares to be purchased by such Underwriter as set forth opposite the name of such Underwriter in Schedule I hereto and the denominator of which is the aggregate number of Firm Shares to be purchased by all of the Underwriters from the Company and all of the Selling Stockholders hereunder and (b) in the event and to the extent that the Underwriters shall exercise the election to purchase Optional Shares as provided below, the Company agrees to sell to each of the Underwriters, and each of the Underwriters, severally and not jointly, agrees to purchase from the Company, at the purchase price per share set forth in clause (a) of this Section 2, that portion of the number of Optional Shares as to which such election shall have been exercised (to be adjusted by you so as to eliminate fractional shares) determined by multiplying such number of Optional Shares by a fraction the numerator of which is the maximum number of Optional Shares which such Underwriter is entitled to purchase as set forth opposite the name of such Underwriter in Schedule I hereto and the denominator of which is the maximum number of Optional Shares that all of the Underwriters are entitled to purchase hereunder.

The Company hereby grants to the Underwriters the right to purchase at their election up to [        ] Optional Shares, at the purchase price per share set forth in the paragraph above, for the sole

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purpose of covering sales of shares in excess of the number of Firm Shares, provided that the purchase price per Optional Share shall be reduced by an amount per share equal to any dividends or distributions declared by the Company and payable on the Firm Shares but not payable on the Optional Shares.  Any such election to purchase Optional Shares may be exercised only by written notice from you to the Company, given within a period of 30 calendar days after the date of this Agreement and setting forth the aggregate number of Optional Shares to be purchased and the date on which such Optional Shares are to be delivered, as determined by you but in no event earlier than the First Time of Delivery (as defined in Section 4 hereof) or, unless you and the Company otherwise agree in writing, earlier than two or later than ten business days after the date of such notice.

3.             Upon the authorization by you of the release of the Firm Shares, the several Underwriters propose to offer the Firm Shares for sale upon the terms and conditions set forth in the Prospectus.

4.             (a)           The Shares to be purchased by each Underwriter hereunder will be represented by one or more definitive global Shares in book-entry form which will be deposited by or on behalf of the Company and the Selling Stockholders with the DTC or its designated custodian.  The Company will, and the Attorneys-in-Fact, or either of them acting alone, (pursuant to each Selling Stockholders Power of Attorney) will cause the Custodian (pursuant to each Selling Stockholder’s Power of Attorney and Custody Agreement) to, deliver the Shares to Thomas Weisel Partners LLC and Piper Jaffray & Co., for the account of each Underwriter, against payment by or on behalf of each such Underwriter of the purchase price therefore by wire transfer of Federal (same-day) funds to the account specified by the Company and the Attorneys-in-Fact, or either of them acting alone (pursuant to each Selling Stockholder’s Power of Attorney), the Attorney-in-Fact, or either of them acting alone, (pursuant to each Selling Stockholder’s Power of Attorney) to Thomas Weisel Partners LLC or Piper Jaffray & Co. by causing DTC to credit the Shares to the account of Thomas Weisel Partners LLC or Piper Jaffray & Co. at DTC.  The time and date of such delivery and payment shall be, with respect to the Firm Shares, [        ] a.m., New York City time, on               , 2010, or such other time and date as Thomas Weisel Partners LLC, Piper Jaffray & Co., the Company and the Attorney-in-Fact, or either of them acting alone, (pursuant to each Selling Stockholder’s Power of Attorney) may agree upon in writing, and, with respect to the Optional Shares, [        ] a.m., New York City time, on the date specified by Thomas Weisel Partners LLC and Piper Jaffray & Co. in the written notice given by Thomas Weisel Partners LLC and Piper Jaffray & Co. of the Underwriters’ election to purchase such Optional Shares, or such other time and date as Thomas Weisel Partners LLC, Piper Jaffray & Co. and the Company, or either of them acting alone, may agree upon in writing.  Such time and date for delivery of the Firm Shares is herein called the “First Time of Delivery”, such time and date for delivery of the Optional Shares, if not the First Time of Delivery, is herein called the “Second Time of Delivery”, and each such time and date for delivery is herein called a “Time of Delivery”.

(b)           The documents to be delivered at each Time of Delivery by or on behalf of the parties hereto pursuant to Section 9 hereof, including the cross receipt for the Shares and any additional documents requested by the Underwriters pursuant to Section 9(l) hereof, will be delivered at the offices of Cooley LLP, 3175 Hanover Street, Palo Alto, California 94306 (the “Closing Location”), and the Shares will be delivered at the office of DTC or its designated custodian (the “Designated Office”), all at such Time of Delivery.  A meeting will be held at the Closing Location at [        ] p.m., New York City time, on the New York Business Day next preceding such Time of Delivery,

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at which meeting the final drafts of the documents to be delivered pursuant to the preceding sentence will be available for review by the parties hereto.  For the purposes of this Section 4, “New York Business Day” shall mean each Monday, Tuesday, Wednesday, Thursday and Friday which is not a day on which banking institutions in New York are generally authorized or obligated by law or executive order to close.

5.             (a)           Each of the Company and the Selling Stockholders, severally and not jointly, acknowledges and agrees that (i) the purchase and sale of the Shares pursuant to this Agreement is an arm’s-length commercial transaction between the Company and the Selling Stockholders, on the one hand, and the several Underwriters, on the other, (ii) in connection therewith and with the process leading to such transaction each Underwriter is acting solely as a principal and not the agent or fiduciary of the Company or the Selling Stockholders, (iii) no Underwriter has assumed an advisory or fiduciary responsibility in favor of the Company or the Selling Stockholders 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 or the Selling Stockholders on other matters) or any other obligation to the Company or the Selling Stockholders except the obligations expressly set forth in this Agreement and (iv) each of the Company and the Selling Stockholders has consulted its own legal and financial advisors to the extent it deemed appropriate.  Each of the Company and the Selling Stockholders, severally and not jointly, agrees that it will not claim that the Underwriters, or any of them, has rendered advisory services in respect of the Offering, or owes a fiduciary or similar duty to the Company or the Selling Stockholders, in connection with such transaction or the process leading thereto.

(b)           This Agreement supersedes all prior agreements and understandings (whether written or oral) between the Company and the Selling Stockholders, on the one hand, and the Underwriters, or any of them, on the other, with respect to the subject matter hereof.

(c)           Each of the Company and the Selling Stockholders, severally and not jointly, and each of the Underwriters hereby irrevocably waives, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to this Agreement or the transactions contemplated hereby.

6.                                     The Company agrees with each of the Underwriters:

(a)           To prepare the Prospectus in a form approved by you and to file such Prospectus pursuant to Rule 424(b) under the Act not later than the Commission’s close of business on the second business day following the execution and delivery of this Agreement, or, if applicable, such earlier time as may be required by Rule 430A(a)(3) under the Act; to make no further amendment or any supplement to the Registration Statement or the Prospectus prior to the last Time of Delivery which shall be disapproved by you promptly after reasonable notice thereof; to advise you, promptly after it receives notice thereof, of the time when any amendment to the Registration Statement has been filed or becomes effective or any supplement to the Prospectus or any amended Prospectus has been filed and to furnish you with copies thereof; to file promptly all material required to be filed by the Company with the Commission pursuant to Rule 433(d) under the Act; to advise you, 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 or other prospectus in respect of the Shares, of the suspension of the qualification of the Shares 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 or the Prospectus or for additional information; and, in the event of the issuance of any stop order or of any order preventing or suspending the use of any

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Preliminary Prospectus or other prospectus or suspending any such qualification, to promptly use its best efforts to obtain the withdrawal of such order;

(b)           Promptly from time to time to take such action as you may reasonably request to qualify the Shares for offering and sale under the securities laws of such jurisdictions as you may request and to comply with such laws so as to permit the continuance of sales and dealings therein in such jurisdictions for as long as may be necessary to complete the distribution of the Shares, provided that in connection therewith the Company shall not be required to qualify as a foreign corporation or to file a general consent to service of process in any jurisdiction;

(c)           Prior to 10:00 A.M., New York City time, on the New York Business Day next succeeding the date of this Agreement and from time to time, to furnish the Underwriters with written and electronic copies of the Prospectus in New York City in such quantities as you may reasonably request, and, if the delivery of a prospectus (or in lieu thereof, the notice referred to in Rule 173(a) under the Act) is required at any time prior to the expiration of nine months after the time of issue of the Prospectus in connection with the offering or sale of the Shares and if at such time any events shall have occurred as a result of which the Prospectus as then amended or supplemented would include an untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made when such Prospectus (or in lieu thereof, the notice referred to in Rule 173(a) under the Act) is delivered, not misleading, or, if for any other reason it shall be necessary during such same period to amend or supplement the Prospectus in order to comply with the Act, to notify you and upon your request to prepare and furnish without charge to each Underwriter and to any dealer in securities as many written and electronic copies as you may from time to time reasonably request of an amended Prospectus or a supplement to the Prospectus which will correct such statement or omission or effect such compliance, and in case any Underwriter is required to deliver a prospectus (or in lieu thereof, the notice referred to in Rule 173(a) under the Act) in connection with sales of any of the Shares at any time nine months or more after the time of issue of the Prospectus, upon your request but at the expense of such Underwriter, to prepare and deliver to such Underwriter as many written and electronic copies as you may request of an amended or supplemented Prospectus complying with Section 10(a)(3) of the Act;

(d)           To make generally available to its securityholders as soon as practicable, but in any event not later than eighteen months after the effective date of the Registration Statement (as defined in Rule 158(c) under the Act), an earning statement of the Company and its subsidiaries (which need not be audited) complying with Section 11(a) of the Act and the rules and regulations of the Commission thereunder (including, at the option of the Company, Rule 158);

(e)           During the period beginning from the date hereof and continuing to and including the date 180 days after the date of the Prospectus (the initial “Lock-Up Period”), not to offer, sell, contract to sell, pledge, grant any option to purchase, make any short sale or otherwise dispose of, except as provided hereunder, any securities of the Company that are substantially similar to the Shares, including but not limited to any options or warrants to purchase shares of Stock or any securities that are convertible into or exchangeable for, or that represent the right to receive, Stock or any such substantially similar securities (other than pursuant to employee stock option plans existing on, or upon the conversion or exchange of other exercisable, convertible or exchangeable securities outstanding as of, the date of this Agreement), without your prior written consent; provided, however, that if (1) during the last 17 days of the initial Lock-Up Period, the Company releases earnings results or announces material news or a material event or (2) prior to the expiration of the initial Lock-Up period, the Company announces that it will release earnings results during the 15-day period following the last day of the initial Lock-Up Period,

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then in each case the Lock-Up Period will be automatically extended until the expiration of the 18-day period beginning on the date of release of the earnings results or the announcement of the material news or material event, as applicable, unless Thomas Weisel Partners LLC and Piper Jaffray & Co. waive, in writing, such extension; the Company will provide the representatives and any co-managers and each stockholder subject to the Lock-Up Period pursuant to the lock-up letters described in Sections 1(b)(v) and 9(i) with prior notice of any such announcement that gives rise to an extension of the Lock-Up Period;

(f)            Unless otherwise publicly available in electronic format on the website of the Company or the Commission, to furnish to its stockholders as soon as practicable after the end of each fiscal year an annual report (including a balance sheet and statements of income, stockholders’ equity and cash flows of the Company and its consolidated subsidiaries certified by independent public accountants) and, as soon as practicable after the end of each of the first three quarters of each fiscal year (beginning with the fiscal quarter ending after the effective date of the Registration Statement), to make available to its stockholders consolidated summary financial information of the Company and its subsidiaries for such quarter in reasonable detail;

(g)           During a period of five years from the effective date of the Registration Statement, unless otherwise publicly available in electronic format on the website of the Company or the Commission, to furnish to you copies of all reports or other communications (financial or other) furnished to stockholders, and to deliver to you as soon as they are available, copies of any reports and financial statements furnished to or filed with the Commission or any national securities exchange on which any class of securities of the Company is listed;

(h)           To use the net proceeds received by it from the sale of the Shares pursuant to this Agreement in the manner specified in the Registration Statement, Pricing Prospectus and Prospectus under the caption “Use of Proceeds”;

(i)            If the Company elects to rely upon Rule 462(b), the Company shall file a Rule 462(b) Registration Statement with the Commission in compliance with Rule 462(b) by 10:00 P.M., Washington, D.C. time, on the date of this Agreement, and the Company shall at the time of filing either pay to the Commission the filing fee for the Rule 462(b) Registration Statement or give irrevocable instructions for the payment of such fee pursuant to Rule 111(b) under the Act; and

(j)            Upon request of any Underwriter, to furnish, or cause to be furnished, to such Underwriter an electronic version of the Company’s trademarks, servicemarks and corporate logo for use on the website, if any, operated by such Underwriter for the purpose of facilitating the on-line offering of the Shares (the “License”); provided, however, that the License shall be used solely for the purpose described above, is granted without any fee and may not be assigned or transferred.

(k)           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 connection with the Company’s initial public offering.  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” or market standoff agreements for the duration of the periods contemplated in such agreements.  The Company agrees not to release or otherwise grant any waiver of such agreements without the prior written consent of each of Thomas Weisel Partners LLC and Piper Jaffray & Co.

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7.                                     (a)            The Company represents and agrees that, without the prior consent of Thomas Weisel Partners LLC and Piper Jaffray & Co., it has not made and will not make any offer relating to the Shares that would constitute a “free writing prospectus” as defined in Rule 405 under the Act; each Underwriter represents and agrees that, without the prior consent of the Company, Thomas Weisel Partners LLC and Piper Jaffray & Co., it has not made and will not make any offer relating to the Shares that would constitute a free writing prospectus; any such free writing prospectus the use of which has been consented to by the Company, Thomas Weisel Partners LLC and Piper Jaffray & Co. is listed on Schedule III hereto;

(b)           The Company has complied and will comply with the requirements of Rule 433 under the Act applicable to any Issuer Free Writing Prospectus, including timely filing with the Commission or retention where required and legending; and the Company represents that it has satisfied and agrees that it will satisfy the conditions under Rule 433 under the Act to avoid a requirement to file with the Commission any electronic road show;

(c)           The Company agrees that if at any time following issuance of an Issuer Free Writing Prospectus any event occurred or occurs as a result of which such Issuer Free Writing Prospectus would conflict with the information in the Registration Statement, the Pricing Prospectus or the Prospectus or would include an untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances then prevailing, not misleading, the Company will give prompt notice thereof to Thomas Weisel Partners LLC and Piper Jaffray & Co. and, if requested by Thomas Weisel Partners LLC and Piper Jaffray & Co., will prepare and furnish without charge to each Underwriter an Issuer Free Writing Prospectus or other document which will correct such conflict, statement or omission; provided, however, that this representation and warranty shall not apply to any statements or omissions in an Issuer Free Writing Prospectus made in reliance upon and in conformity with information furnished in writing to the Company by an Underwriter through Thomas Weisel Partners LLC and Piper Jaffray & Co. expressly for use therein.

8.                                     The Company covenants and agrees with the several Underwriters that the Company will pay or cause to be paid the following: (i) the fees, disbursements and expenses of the Company’s counsel and accountants and up to $25,000 for one counsel for the Selling Stockholders in connection with the registration of the Shares under the Act and all other expenses in connection with the preparation, printing, reproduction and filing of the Registration Statement, any Preliminary Prospectus, any Issuer Free Writing Prospectus and the Prospectus and amendments and supplements thereto and the mailing and delivering of copies thereof to the Underwriters and dealers; (ii) the cost of printing or producing any Agreement among Underwriters, this Agreement, the Blue Sky Memorandum, closing documents (including any compilations thereof) and any other documents in connection with the offering, purchase, sale and delivery of the Shares; (iii) all expenses in connection with the qualification of the Shares for offering and sale under state securities laws as provided in Section 6(b) hereof, including the fees and disbursements of counsel for the Underwriters in connection with such qualification and in connection with the Blue Sky survey; (iv) all fees and expenses in connection with listing the Shares on the NASDAQ; (v) the filing fees incident to, and the fees and disbursements of counsel for the Underwriters in connection with, securing any required review by the FINRA of the terms of the sale of the Shares; (vi) the cost of preparing stock certificates; (vii) the cost and charges of any transfer agent or registrar (viii) the fees and expenses of the Attorneys-in-Fact and the Custodian; (ix) all expenses (other than taxes) incident to the sale and delivery of the Shares to be sold by the Selling Stockholders to the Underwriters hereunder; and (x) all other costs and expenses incident to the performance of its obligations hereunder which are not otherwise specifically provided for in this Section.  Each of the Selling Stockholders, severally and not jointly, covenants and agrees that such Selling Stockholder will

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pay or cause to be paid (i) to the extent not paid by the Company pursuant to subparagraph (i) of the preceding sentence, the fees and expenses of such Selling Stockholder’s counsel in connection with the registration of the Shares under the Act (such fees and expenses to be paid from the proceeds from the sale of Selling Stockholder’s Shares to the Underwriters hereunder to the accounts specified to the Underwriters by the Attorneys-in-Fact, or either of them acting along (pursuant to such Selling Stockholder’s Power of Attorney)), (ii) taxes incident to the sale and delivery of the Shares to be sold by such Selling Stockholder to the Underwriters hereunder, and (iii) any other fees and expenses as may be provided for in any separate agreement relating to the allocation of payment of expenses between the Company, on the one hand, and the Selling Stockholders, on the other hand; provided that to the extent the Selling Stockholders fail to pay any expense provided for herein, the Company shall pay such expense and shall look solely to the Selling Stockholders for reimburesement.  In connection with the preceding sentence, Thomas Weisel Partners LLC and Piper Jaffray & Co. agree to pay New York State stock transfer tax, and each Selling Stockholder, severally and not jointly, agrees to reimburse Thomas Weisel Partners LLC and Piper Jaffray & Co. for associated carrying costs if such tax payment is not rebated on the day of payment and for any portion of such tax payment not rebated. It is further understood that, except as provided in this Section, and Sections 10 and 13 hereof, the Underwriters will pay all of their own costs and expenses, including the fees of their counsel, stock transfer taxes on resale of any of the Shares by them, and any advertising expenses connected with any offers they may make.

9.                                     The obligations of the Underwriters hereunder, as to the Shares to be delivered at each Time of Delivery, shall be subject, in their discretion, to the condition that all representations and warranties and other statements of the Company and of the Selling Stockholders herein are, at and as of such Time of Delivery, true and correct, the condition that the Company and the Selling Stockholders shall have performed all of its and their obligations hereunder theretofore to be performed, and the following additional conditions:

(a)           The Prospectus shall have been filed with the Commission pursuant to Rule 424(b) under the Act within the applicable time period prescribed for such filing by the rules and regulations under the Act and in accordance with Section 6(a) hereof; all material required to be filed by the Company pursuant to Rule 433(d) under the Act shall have been filed with the Commission within the applicable time period prescribed for such filing by Rule 433; if the Company has elected to rely upon Rule 462(b) under the Act, the Rule 462(b) Registration Statement shall have become effective by 10:00 P.M., Washington, D.C. time, on the date of this Agreement; no stop order suspending the effectiveness of the Registration Statement or any part thereof shall have been issued and no proceeding for that purpose shall have been initiated or threatened by the Commission; no stop order suspending or preventing the use of the Prospectus or any Issuer Free Writing Prospectus shall have been initiated or threatened by the Commission; and all requests for additional information on the part of the Commission shall have been complied with to your reasonable satisfaction;

(b)           Cooley LLP, counsel for the Underwriters, shall have furnished to you such written opinion or opinions, dated such Time of Delivery, in the form attached as Annex II(a) hereto;

(c)           DLA Piper US LLP, counsel for the Company, shall have furnished to you their written opinion and letter, dated such Time of Delivery, in the forms attached as Annex II(b) hereto;

(d)           Taylor Russell & Russell, P.C., intellectual property counsel for the Company, shall have furnished to you their written opinion, dated such Time of Delivery, in the form attached as Annex II(c) hereto;

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(e)           The respective counsel for each of the Selling Stockholders, as indicated in Schedule II hereto, each shall have furnished to you their written opinion with respect to each of the Selling Stockholders for whom they are acting as counsel (a form of each such opinion is attached as Annex II(d) hereto), dated such Time of Delivery, in form and substance satisfactory to you;

(f)            On the date of the Prospectus at a time prior to the execution of this Agreement, at 9:30 a.m., New York City time, on the effective date of any post-effective amendment to the Registration Statement filed subsequent to the date of this Agreement and also at each Time of Delivery, Ernst & Young LLP shall have furnished to you a letter or letters, dated the respective dates of delivery thereof, in form and substance satisfactory to you, to the effect set forth in Annex I hereto (the executed copy of the letter delivered prior to the execution of this Agreement is attached as Annex I(a) hereto and a draft of the form of letter to be delivered on the effective date of any post-effective amendment to the Registration Statement and as of each Time of Delivery is attached as Annex I(b) hereto);

(g)           (i) Neither the Company nor any of its subsidiaries shall have sustained since the date of the latest audited financial statements included in the Pricing Prospectus any loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor dispute or court or governmental action, order or decree, otherwise than as set forth or contemplated in the Pricing Prospectus, and (ii) since the respective dates as of which information is given in the Pricing Prospectus there shall not have been any change in the capital stock or long-term debt of the Company or any of its subsidiaries or any change, or any development involving a prospective change, in or affecting the business, operations, assets, condition (financial or otherwise) or results of operations of the Company and its consolidated subsidiaries, otherwise than as set forth or contemplated in the Pricing Prospectus, the effect of which, in any such case described in clause (i) or (ii), is in the judgment of Thomas Weisel Partners LLC and Piper Jaffray & Co. so material and adverse as to make it impracticable or inadvisable to proceed with the public offering or the delivery of the Shares being delivered at such Time of Delivery on the terms and in the manner contemplated in the Pricing Prospectus;

(h)           On or after the Applicable Time there shall not have occurred any of the following: (i) a suspension or material limitation in trading in securities generally on the NYSE or on NASDAQ; (ii) a suspension or material limitation in trading in the Company’s securities on NASDAQ; (iii) a general moratorium on commercial banking activities declared by either Federal or New York or Texas State authorities or a material disruption in commercial banking or securities settlement or clearance services in the United States; (iv) the outbreak or escalation of hostilities involving the United States or the declaration by the United States of a national emergency or war or (v) the occurrence of any other calamity or crisis or any change in financial, political or economic conditions in the United States or elsewhere, if the effect of any such event specified in clause (iv) or (v) in your judgment makes it impracticable or inadvisable to proceed with the public offering or the delivery of the Shares being delivered at such Time of Delivery on the terms and in the manner contemplated in the Prospectus;

(i)            The Shares to be sold at such Time of Delivery shall have been duly listed for quotation on NASDAQ, subject to official notice of issuance;

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(j)            The Company has obtained and delivered to the Underwriters executed copies of a Lock-up Agreement from each officer and director, and from the holders of substantially all the shares of capital stock of the Company, substantially in the form attached as Annex III hereto;

(k)           The Company shall have complied with the provisions of Section 6(c) hereof with respect to the furnishing of prospectuses on the New York Business Day next succeeding the date of this Agreement;

(l)            The Company shall have furnished or caused to be furnished to you at such Time of Delivery certificates of officers of the Company satisfactory to you as to the accuracy of the representations and warranties of the Company herein at and as of such Time of Delivery, as to the performance by the Company of all of its obligations hereunder to be performed at or prior to such Time of Delivery, and as to such other matters as you may reasonably request, and the Company shall have furnished or caused to be furnished certificates as to the matters set forth in subsections (a) and (h) of this Section; and

(m)          The Selling Stockholders shall have furnished, or caused to be furnished to you, at such Time of Delivery certificates of the Selling Stockholders substantially in the form attached hereto as Annex IV.

10.                               (a) The Company will indemnify and hold harmless each Underwriter and each of the Selling Stockholders against any losses, claims, damages or liabilities, joint or several, to which such Underwriter or Selling Stockholder may become subject, under the Act or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon an untrue statement or alleged untrue statement of a material fact contained in the Registration Statement, any Preliminary Prospectus, the Pricing Prospectus or the Prospectus, or any amendment or supplement thereto, or any Issuer Free Writing Prospectus or any “issuer information” filed or required to be filed pursuant to Rule 433(d) under the Act, or arise out of or are 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, and will reimburse each Underwriter and Selling Stockholder for any legal or other expenses reasonably incurred by such Underwriter or Selling Stockholder in connection with investigating or defending any such action or claim as such expenses are incurred; provided, however, that the Company shall not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or is based upon an untrue statement or alleged untrue statement or omission or alleged omission made in the Registration Statement, any Preliminary Prospectus, the Pricing Prospectus or the Prospectus or any amendment or supplement thereto, or any Issuer Free Writing Prospectus or any “issuer information” filed or required to be filed pursuant to Rule 433(d) under the Act, in reliance upon and in conformity with, in the case of an Underwriter, written information furnished to the Company by any Underwriter through Thomas Weisel Partners LLC or Piper Jaffray & Co. expressly for use therein.

(b)           Each Selling Stockholder, severally and not jointly, will indemnify and hold harmless the Company and each Underwriter against any losses, claims, damages or liabilities to which the Company or such Underwriter may become subject, under the Act or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon an untrue statement or alleged untrue statement of a material fact contained in the Registration Statement, any Preliminary Prospectus, the Pricing Prospectus or the Prospectus, or any amendment or supplement thereto, or any Issuer Free Writing Prospectus, or arise out of or are 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

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alleged untrue statement or omission or alleged omission was made in the Registration Statement, any Preliminary Prospectus, the Pricing Prospectus or the Prospectus, or any amendment or supplement thereto, or any Issuer Free Writing Prospectus, in reliance upon and in conformity with information relating to a Selling Stockholder furnished to the Company in writing by such Selling Stockholder expressly for use therein; and will reimburse the Company and each Underwriter for any legal or other expenses reasonably incurred by the Company or such Underwriter in connection with investigating or defending any such action or claim as such expenses are incurred.

(c)           Each Underwriter will indemnify and hold harmless the Company and each Selling Stockholder against any losses, claims, damages or liabilities to which the Company or such Selling Stockholder may become subject, under the Act or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon an untrue statement or alleged untrue statement of a material fact contained in the Registration Statement, any Preliminary Prospectus, the Pricing Prospectus or the Prospectus, or any amendment or supplement thereto, or any Issuer Free Writing Prospectus, or arise out of or are 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, any Preliminary Prospectus, the Pricing Prospectus or the Prospectus, or any amendment or supplement thereto, or any Issuer Free Writing Prospectus, in reliance upon and in conformity with written information furnished to the Company by such Underwriter through Thomas Weisel Partners LLC or Piper Jaffray & Co. expressly for use therein; and will reimburse the Company and each Selling Stockholder for any legal or other expenses reasonably incurred by the Company or such Selling Stockholder in connection with investigating or defending any such action or claim as such expenses are incurred.

(d)           Promptly after receipt by an indemnified party under subsection (a), (b) or (c) above of notice of the commencement of any action, such indemnified party shall, if a claim in respect thereof is to be made against the indemnifying party under such subsection, notify the indemnifying party in writing of the commencement thereof; but the omission so to notify the indemnifying party shall not relieve it from any liability which it may have to any indemnified party otherwise than under such subsection.  In case any such action shall be brought against any indemnified party and it shall notify the indemnifying party of the commencement thereof, the indemnifying party shall be entitled to participate therein and, to the extent that it shall wish, jointly with any other indemnifying party similarly notified, to assume the defense thereof, with counsel satisfactory to such indemnified party (who shall not, except with the consent of the indemnified party, be counsel to the indemnifying party), and, after notice from the indemnifying party to such indemnified party of its election so to assume the defense thereof, the indemnifying party shall not be liable to such indemnified party under such subsection for any legal expenses of other counsel or any other expenses, in each case subsequently incurred by such indemnified party, in connection with the defense thereof other than reasonable costs of investigation.  No indemnifying party shall, without the written consent of the indemnified party, effect the settlement or compromise of, or consent to the entry of any judgment with respect to, any pending or threatened action or claim in respect of which indemnification or contribution may be sought hereunder (whether or not the indemnified party is an actual or potential party to such action or claim) unless such settlement, compromise or judgment (i) includes an unconditional release of the indemnified party from all liability arising out of such action or claim and (ii) does not include a statement as to or an admission of fault, culpability or a failure to act, by or on behalf of any indemnified party.

(e)           If the indemnification provided for in this Section 10 is unavailable to or insufficient to hold harmless an indemnified party under subsection (a), (b) or (c) above in respect of any

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losses, claims, damages or liabilities (or actions in respect thereof) referred to therein, then each indemnifying party shall contribute to the amount paid or payable by such indemnified party as a result of such losses, claims, damages or liabilities (or actions in respect thereof) in such proportion as is appropriate to reflect the relative benefits received by the Company and the Selling Stockholders on the one hand and the Underwriters on the other from the offering of the Shares.  If, however, the allocation provided by the immediately preceding sentence is not permitted by applicable law or if the indemnified party failed to give the notice required under subsection (d) above, then each indemnifying party shall contribute to such amount paid or payable by such indemnified party in such proportion as is appropriate to reflect not only such relative benefits but also the relative fault of the Company and the Selling Stockholders on the one hand and the Underwriters on the other in connection with the statements or omissions which resulted in such losses, claims, damages or liabilities (or actions in respect thereof), as well as any other relevant equitable considerations.  The relative benefits received by the Company and the Selling Stockholders on the one hand and the Underwriters on the other shall be deemed to be in the same proportion as the total net proceeds from the offering (before deducting expenses) received by the Company and the Selling Stockholders bear to the total underwriting discounts and commissions received by the Underwriters, in each case as set forth in the table on the cover page of the Prospectus.  The relative fault shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company or the Selling Stockholders on the one hand or the Underwriters on the other and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.  The Company, each of the Selling Stockholders and the Underwriters agree that it would not be just and equitable if contributions pursuant to this subsection (e) 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 above in this subsection (e).  The amount paid or payable by an indemnified party as a result of the losses, claims, damages or liabilities (or actions in respect thereof) referred to above in this subsection (e) shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in connection with investigating or defending any such action or claim.  Notwithstanding the provisions of this subsection (e), no Underwriter shall be required to contribute any amount in excess of the amount by which the total price at which the Shares underwritten by it and distributed to the public were offered to the public exceeds the amount of any damages which such Underwriter has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission.  No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation.  The Underwriters’ obligations in this subsection (e) to contribute are several in proportion to their respective underwriting obligations and not joint.

(f)            The obligations of the Company and the Selling Stockholders under this Section 10 shall be in addition to any liability which the Company and the respective Selling Stockholders may otherwise have and shall extend, upon the same terms and conditions, to each person, if any, who controls any Underwriter within the meaning of the Act and each broker-dealer affiliate of any Underwriter; and the obligations of the Underwriters under this Section 10 shall be in addition to any liability which the respective Underwriters may otherwise have and shall extend, upon the same terms and conditions, to each officer and director of the Company and to each person, if any, who controls the Company or any Selling Stockholder within the meaning of the Act.

(g)           Notwithstanding anything in this Agreement to the contrary, the liability of each Selling Stockholder under this Section 10 (under the indemnity or contribution provisions or otherwise)

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shall be limited to an amount equal to the initial public offering price of the Shares sold by such Selling Stockholder, less the underwriting discount, as set forth on the front cover page of the Prospectus.

11.                               If any Underwriter shall default in its obligation to purchase the Shares which it has agreed to purchase hereunder at a Time of Delivery, you may in your discretion arrange for you or another party or other parties to purchase such Shares on the terms contained herein.  If within thirty-six hours after such default by any Underwriter you do not arrange for the purchase of such Shares, then the Company and the Selling Stockholders shall be entitled to a further period of thirty-six hours within which to procure another party or other parties satisfactory to you to purchase such Shares on such terms.  In the event that, within the respective prescribed periods, you notify the Company and the Selling Stockholders that you have so arranged for the purchase of such Shares, or the Company and the Selling Stockholders notify you that they have so arranged for the purchase of such Shares, you or the Company and the Selling Stockholders shall have the right to postpone a Time of Delivery for a period of not more than seven days, in order to effect whatever changes may thereby be made necessary in the Registration Statement or the Prospectus, or in any other documents or arrangements, and the Company agrees to file promptly any amendments or supplements to the Registration Statement or the Prospectus which in your opinion may thereby be made necessary.  The term “Underwriter” as used in this Agreement shall include any person substituted under this Section with like effect as if such person had originally been a party to this Agreement with respect to such Shares.

(a)           If, after giving effect to any arrangements for the purchase of the Shares of a defaulting Underwriter or Underwriters by you and the Company and the Selling Stockholders as provided in subsection (a) above, the aggregate number of such Shares which remains unpurchased does not exceed one-eleventh of the aggregate number of all the Shares to be purchased at such Time of Delivery, then the Company and the Selling Stockholders shall have the right to require each non-defaulting Underwriter to purchase the number of Shares which such Underwriter agreed to purchase hereunder at such Time of Delivery and, in addition, to require each non-defaulting Underwriter to purchase its pro rata share (based on the number of Shares which such Underwriter agreed to purchase hereunder) of the Shares of such defaulting Underwriter or Underwriters for which such arrangements have not been made; but nothing herein shall relieve a defaulting Underwriter from liability for its default.

(b)           If, after giving effect to any arrangements for the purchase of the Shares of a defaulting Underwriter or Underwriters by you and the Company and the Selling Stockholders as provided in subsection (a) above, the aggregate number of such Shares which remains unpurchased exceeds one-eleventh of the aggregate number of all of the Shares to be purchased at such Time of Delivery, or if the Company and the Selling Stockholders shall not exercise the right described in subsection (b) above to require non-defaulting Underwriters to purchase Shares of a defaulting Underwriter or Underwriters, then this Agreement (or, with respect to the Second Time of Delivery, the obligations of the Underwriters to purchase and of the Company to sell the Optional Shares) shall thereupon terminate, without liability on the part of any non-defaulting Underwriter or the Company or the Selling Stockholders, except for the expenses to be borne by the Company and the Selling Stockholders and the Underwriters as provided in Section 8 hereof and the indemnity and contribution agreements in Section 10 hereof; but nothing herein shall relieve a defaulting Underwriter from liability for its default.

12.                               The respective indemnities, agreements, representations, warranties and other statements of the Company, the Selling Stockholders and the several Underwriters, as set forth in this Agreement or made by or on behalf of them, respectively, pursuant to this Agreement, shall remain in full force and

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effect, regardless of any investigation (or any statement as to the results thereof) made by or on behalf of any Underwriter or any controlling person of any Underwriter, or the Company, or any of the Selling Stockholders, or any officer or director or controlling person of the Company, or any controlling person of any Selling Stockholder, and shall survive delivery of and payment for the Shares.

13.           If this Agreement shall be terminated pursuant to Section 11 hereof, neither the Company nor the Selling Stockholders shall then be under any liability to any Underwriter except as provided in Section 10 and  Section 13 hereof; but, if for any other reason any Shares are not delivered by or on behalf of the Company and the Selling Stockholders as provided herein, the Company will reimburse the Underwriters through you for all out-of-pocket expenses approved in writing by you, including fees and disbursements of counsel, reasonably incurred by the Underwriters in making preparations for the purchase, sale and delivery of the Shares not so delivered, but the Company and the Selling Stockholders shall then be under no further liability to any Underwriter in respect of the Shares not so delivered except as provided in Section 10 and Section 13 hereof.

14.           In all dealings hereunder, you shall act on behalf of each of the Underwriters, and the parties hereto shall be entitled to act and rely upon any statement, request, notice or agreement on behalf of any Underwriter made or given by you jointly or by Thomas Weisel Partners LLC and Piper Jaffray & Co. on behalf of you as the representatives; and in all dealings with any Selling Stockholder hereunder, you and the Company shall be entitled to act and rely upon any statement, request, notice or agreement on behalf of such Selling Stockholder made or given by any or all of the Attorneys-in-Fact for such Selling Stockholder.

All statements, requests, notices and agreements hereunder shall be in writing, and if to the Underwriters shall be delivered or sent by mail, telex or facsimile transmission to you as the representatives in care of Thomas Weisel Partners LLC, One Montgomery Street, Suite 3700, San Francisco, CA 94104, Attention: General Counsel and to Piper Jaffray & Co., Suite 800, 800 Nicollet Mall, Minneapolis, MN 55402, Attention: General Counsel; if to any Selling Stockholder shall be delivered or sent by mail, telex or facsimile transmission to the Attorneys-in-Fact to the address set forth in the Power of Attorney; and if to the Company shall be delivered or sent by mail, telex or facsimile transmission to the address of the Company set forth in the Registration Statement, Attention: Secretary; provided, however, that any notice to an Underwriter pursuant to Section 10(e) hereof shall be delivered or sent by mail, telex or facsimile transmission to such Underwriter at its address set forth in its Underwriters’ Questionnaire or telex constituting such Questionnaire, which address will be supplied to the Company or the Selling Stockholders by you on request; provided, however, that notices under Section 6(e) shall be in writing, and if to the Underwriters shall be delivered or sent by mail, telex or facsimile transmission to you as the representatives at Thomas Weisel Partners LLC, One Montgomery Street, Suite 3700, San Francisco, CA 94104, Attention: General Counsel  and to Piper Jaffray & Co., Suite 800, 800 Nicollet Mall, Minneapolis, MN 55402, Attention: General Counsel; if to any other signatory to an agreement referred to in Section 9(i), to the address listed on the signature page thereto.  Any such statements, requests, notices or agreements shall take effect upon receipt thereof.

In accordance with the requirements of the USA Patriot Act (Title III of Pub. L. 107-56 (signed into law October 26, 2001)), the underwriters are required to obtain, verify and record information that identifies their respective clients, including the Company, which information may include the name and address of their respective clients, as well as other information that will allow the underwriters to properly identify their respective clients.

15.           This Agreement shall be binding upon, and inure solely to the benefit of, the Underwriters, the Company and the Selling Stockholders and, to the extent provided in Sections 10 and

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12 hereof, the officers and directors of the Company and each person who controls the Company, any Selling Stockholder or any Underwriter, and their respective heirs, executors, administrators, successors and assigns, and no other person shall acquire or have any right under or by virtue of this Agreement.  No purchaser of any of the Shares from any Underwriter shall be deemed a successor or assign by reason merely of such purchase.

16.           Time shall be of the essence of this Agreement.  As used herein, the term “business day” shall mean any day when the Commission’s office in Washington, D.C. is open for business.

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

18.           This Agreement may be executed by any one or more of the parties hereto in any number of counterparts, each of which shall be deemed to be an original, but all such counterparts shall together constitute one and the same instrument.

19.           Notwithstanding anything herein to the contrary, the Company and the Selling Stockholders are authorized to disclose to any persons the U.S. federal and state income tax treatment and tax structure of the potential transaction contemplated by this Agreement and all materials of any kind (including tax opinions and other tax analyses) provided to the Company and the Selling Stockholders relating to that treatment and structure, without the Underwriters imposing any limitation of any kind.  However, any information relating to the tax treatment and tax structure shall remain confidential (and the foregoing sentence shall not apply) to the extent necessary to enable any person to comply with securities laws.  For this purpose, “tax structure” is limited to any facts that may be relevant to that treatment.

If the foregoing is in accordance with your understanding, please sign and return to us one for the Company and each of the Representatives plus one for each counsel, of any counterparts hereof, and upon the acceptance hereof by you, on behalf of each of the Underwriters, this letter and such acceptance hereof shall constitute a binding agreement among each of the Underwriters, the Company and each of the Selling Stockholders, severally and not jointly.  It is understood that your acceptance of this letter on behalf of each of the Underwriters is pursuant to the authority set forth in a form of Agreement among Underwriters, the form of which shall be submitted to the Company and the Selling Stockholders for examination, upon request, but without warranty on your part as to the authority of the signers thereof.

Any person executing and delivering this Agreement as Attorney-in-Fact for a Selling Stockholder represents by so doing that he has been duly appointed as Attorney-in-Fact by such Selling Stockholder pursuant to a validly existing and binding Power-of-Attorney which authorizes such Attorney-in-Fact to take such action.

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SCHEDULE I

SCHEDULE II

(a)       All the Selling Stockholders are represented by Vinson & Elkins LLP and have appointed Gene Austin and James Offerdahl, and each of them, as the Attorneys-in-Fact for such Selling Stockholder.

SCHEDULE III

ISSUER FREE WRITING PROSPECTUSES

Electronic roadshow as filed on www.retailroadshow.com.

Electronic roadshow as filed on www.netroadshow.com.