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                                                                     Exhibit 1.1


                                [_____] SHARES(1)

                                 METABOLIX, INC.

                                  COMMON STOCK

                               PURCHASE AGREEMENT


                                                              November [_], 2006


PIPER JAFFRAY & CO.
JEFFERIES & CO.
THOMAS WEISEL PARTNERS LLC
ARDOUR CAPITAL INVESTMENTS
  As Representatives of the several
  Underwriters named in Schedule I hereto
c/o Piper Jaffray & Co.
800 Nicollet Mall
Minneapolis, Minnesota 55402

Ladies and Gentlemen:

         Metabolix, Inc., a Delaware corporation (the "COMPANY"), proposes to
sell to the several Underwriters named in Schedule I hereto (the "UNDERWRITERS")
an aggregate of [_____] shares (the "FIRM SHARES") of Common Stock, $0.01 par
value per share (the "COMMON STOCK"), of the Company. The Company has also
granted to the several Underwriters an option to purchase up to [_____]
additional shares of Common Stock on the terms and for the purposes set forth in
Section 3 hereof (the "OPTION SHARES"). The Firm Shares and any Option Shares
purchased pursuant to this Purchase Agreement are herein collectively called the
"SECURITIES."

         The Company hereby confirms its agreement with respect to the sale of
the Securities to the several Underwriters, for whom you are acting as
representatives (the "REPRESENTATIVES").

         1. REGISTRATION STATEMENT AND PROSPECTUS. A registration statement on
Form S-1 (File No. 333-135760) with respect to the Securities, including a
preliminary form of prospectus, has been prepared by the Company in conformity
with the requirements of the Securities Act of 1933, as amended (the "ACT"), and
the rules and regulations ("RULES AND REGULATIONS") of the Securities and
Exchange Commission (the "COMMISSION") thereunder and has been filed with the
Commission; one or more amendments to such registration statement have also been
so prepared and have been, or will be, so filed; and, if the Company has elected
to rely upon Rule 462(b) of the Rules and Regulations to increase the size of
the offering

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(1)   Plus an option to purchase up to [_____] additional shares to cover
      over-allotments.

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registered under the Act, the Company will prepare and file with the Commission
a registration statement with respect to such increase pursuant to Rule 462(b).
Copies of such registration statement(s) and amendments and each related
preliminary prospectus have been delivered to you.

         If the Company has elected not to rely upon Rule 430A of the Rules and
Regulations, the Company has prepared and will promptly file an amendment to the
registration statement and an amended prospectus. If the Company has elected to
rely upon Rule 430A of the Rules and Regulations, it will prepare and file a
prospectus pursuant to Rule 424(b) that discloses the information previously
omitted from the prospectus in reliance upon Rule 430A. Each part of such
registration statement as amended at the time it is or was declared effective by
the Commission, and, in the event of any amendment thereto after the effective
date, each part of such registration statement as so amended (but only from and
after the effectiveness of such amendment, including a registration statement
(if any) filed pursuant to Rule 462(b) of the Rules and Regulations increasing
the size of the offering registered under the Act) and information (if any)
deemed to be part of the registration statement at the time of effectiveness
pursuant to Rules 430A(b) of the Rules and Regulations, is hereinafter called
the "Registration Statement." The prospectus included in the Registration
Statement at the time it is or was declared effective by the Commission is
hereinafter called the "Prospectus," except that if any prospectus filed by the
Company with the Commission pursuant to Rule 424(b) of the Rules and Regulations
or any other such prospectus provided to the Underwriters by the Company for use
in connection with the offering of the Securities (whether or not required to be
filed by the Company with the Commission pursuant to Rule 424(b) of the Rules
and Regulations, but not including a "free writing prospectus" as defined in
Rule 405 of the Rules and Regulations) differs from the prospectus on file at
the time the Registration Statement is or was declared effective by the
Commission, the term "Prospectus" shall refer to such differing prospectus from
and after the time such prospectus is filed with the Commission or transmitted
to the Commission for filing pursuant to such Rule 424(b) or from and after the
time of its first use within the meaning of the Rules and Regulations. The term
"Preliminary Prospectus" as used herein means any preliminary prospectus
included in the Registration Statement prior to the time it becomes or became
effective under the Act and any prospectus subject to completion as described in
Rule 430A of the Rules and Regulations. All references in this Agreement to the
Registration Statement, any Preliminary Prospectus, the Prospectus or any
amendment or supplement to any of the foregoing, shall be deemed to include the
copy filed with the Commission pursuant to its Electronic Data Gathering,
analysis and Retrieval System ("EDGAR").

         2. REPRESENTATIONS AND WARRANTIES OF THE COMPANY.

            (a) The Company represents and warrants to, and agrees with, the
several Underwriters as follows:

                  (i) No order preventing or suspending the use of any
         Preliminary Prospectus has been issued by the Commission and each
         Preliminary Prospectus, at the time of filing thereof or the time of
         first use within the meaning of the Rules and


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         Regulations, complied in all material respects with the requirements of
         the Securities Act and the Rules and Regulations 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; except that the foregoing shall not apply to statements
         in or omissions from any Preliminary Prospectus in reliance upon, and
         in conformity with, written information furnished to the Company by
         you, or by any Underwriter through you, specifically for use in the
         preparation thereof.

                  (ii) As of the time any part of the Registration Statement (or
         any post-effective amendment thereto, including a registration
         statement (if any) filed pursuant to Rule 462(b) of the Rules and
         Regulations increasing the size of the offering registered under the
         Act) became effective, upon the filing or first use (within the meaning
         of the Rules and Regulations) of the Prospectus (or any supplement to
         the Prospectus) and at the First Closing Date and Second Closing Date
         (as hereinafter defined), (A) the Registration Statement and the
         Prospectus (in each case, as so amended and/or supplemented) conformed
         or will conform in all material respects to the requirements of the Act
         and the Rules and Regulations, (B) the Registration Statement (as so
         amended) did not or will not include 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 not misleading, and (C) the
         Prospectus (as so supplemented) did not or will not include 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
         light of the circumstances in which they are or were made, not
         misleading; except that the foregoing shall not apply to statements in
         or omissions from any such document in reliance upon, and in conformity
         with, written information furnished to the Company by you, or by any
         Underwriter through you, specifically for use in the preparation
         thereof. If the Registration Statement has been declared effective by
         the Commission, no stop order suspending the effectiveness of the
         Registration Statement has been issued, and no proceeding for that
         purpose has been initiated or, to the Company's knowledge, threatened
         by the Commission.

                  (iii) Neither (A) the Issuer General Free Writing
         Prospectus(es) issued at or prior to the Time of Sale and the Statutory
         Prospectus, all considered together (collectively, the "TIME OF SALE
         DISCLOSURE PACKAGE"), nor (B) any individual Issuer Limited-Use Free
         Writing Prospectus, when considered together with the Time of Sale
         Disclosure Package, includes or included as of the Time of Sale any
         untrue statement of a material fact or omit or omitted as of the Time
         of Sale 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. The preceding sentence does not apply to
         statements in or omissions from any Statutory Prospectus included in
         the Registration Statement or any Issuer Free Writing Prospectus based
         upon and in conformity with written information furnished to the
         Company by you or by any Underwriter through you specifically for use
         therein. As used in this paragraph and elsewhere in this Agreement:


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                           (1) "TIME OF SALE" means [____] am (Eastern time) on
                  the date of this Agreement.

                           (2) "STATUTORY PROSPECTUS" as of any time means the
                  prospectus that is included in the Registration Statement
                  immediately prior to that time. For purposes of this
                  definition, information contained in a form of prospectus that
                  is deemed retroactively to be a part of the Registration
                  Statement pursuant to Rule 430A shall be considered to be
                  included in the Statutory Prospectus as of the actual time
                  that form of prospectus is filed with the Commission pursuant
                  to Rule 424(b) under the Act.

                           (3) "ISSUER FREE WRITING PROSPECTUS" means any
                  "issuer free writing prospectus," as defined in Rule 433 under
                  the Act, relating to the Securities that (A) is required to be
                  filed with the Commission by the Company, or (B) is exempt
                  from filing pursuant to Rule 433(d)(5)(i) under the Act
                  because it contains a description of the Securities or of the
                  offering that does not reflect the final terms or pursuant to
                  Rule 433(d)(8)(ii) because it is a "bona fide electronic road
                  show," as defined in Rule 433 of the Rules and Regulations,
                  which is made available by the Company without restriction, in
                  each case in the form filed or required to be filed with the
                  Commission or, if not required to be filed, in the form
                  retained in the Company's records pursuant to Rule 433(g)
                  under the Act.

                           (4) "ISSUER GENERAL FREE WRITING PROSPECTUS" means
                  any Issuer Free Writing Prospectus that is intended for
                  general distribution to prospective investors, as evidenced by
                  its being specified in Schedule II to this Agreement.

                           (5) "ISSUER LIMITED-USE FREE WRITING PROSPECTUS"
                  means any Issuer Free Writing Prospectus that is not an Issuer
                  General Free Writing Prospectus. The term Issuer Limited-Use
                  Free Writing Prospectus also includes any "bona fide
                  electronic road show," as defined in Rule 433 of the Rules and
                  Regulations, that is made available without restriction
                  pursuant to Rule 433(d)(8)(ii), even though not required to be
                  filed with the Commission.

                  (iv) (A) Each Issuer Free Writing Prospectus, as of its issue
         date and at all subsequent times through the completion of the public
         offer and sale of the Securities or until any earlier date that the
         Company notified or notifies the Representatives as described in
         Section 4(a)(iii)(B), did not, does not and will not include any
         information that conflicted, conflicts or will conflict with the
         information contained in the Registration Statement, any Statutory
         Prospectus or the Prospectus. The foregoing sentence does not apply to
         statements in or omissions from any Issuer Free Writing Prospectus
         based upon and in conformity with written information furnished to the
         Company by you or by any Underwriter through you specifically for use
         therein.


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                  (B) (1) At the time of filing the Registration Statement and
         (2) at the date hereof, the Company was not and is not an "ineligible
         issuer," as defined in Rule 405 under the Act, including the Company in
         the preceding three years not having been convicted of a felony or
         misdemeanor or having been made the subject of a judicial or
         administrative decree or order as described in Rule 405 (without taking
         account of any determination by the Commission pursuant to Rule 405
         that it is not necessary that the Company be considered an ineligible
         issuer), nor an "excluded issuer" as defined in Rule 164 under the Act.

                  (C) Each Issuer Free Writing Prospectus satisfied, as of its
         issue date and at all subsequent times through the completion of the
         public offer and sale of the Securities, all other conditions to use
         thereof as set forth in Rules 164 and 433 under the Act.

                  (v) The financial statements of the Company, together with the
         related notes, set forth in the Registration Statement, the Time of
         Sale Disclosure Package and Prospectus comply in all material respects
         with the requirements of the Act and fairly present the financial
         condition of the Company as of the dates indicated and the results of
         operations and changes in cash flows for the periods therein specified
         in conformity with generally accepted accounting principles
         consistently applied throughout the periods involved; and the
         supporting schedules included in the Registration Statement present
         fairly the information required to be stated therein. No other
         financial statements or schedules are required to be included in the
         Registration Statement, the Time of Sale Disclosure Package or the
         Prospectus. To the Company's knowledge, PricewaterhouseCoopers LLP,
         which has expressed its opinion with respect to the financial
         statements and schedules filed as a part of the Registration Statement
         and included in the Registration Statement, the Time of Sale Disclosure
         Package and the Prospectus, is (x) an independent public accounting
         firm within the meaning of the Act and the Rules and Regulations, (y) a
         registered public accounting firm (as defined in Section 2(a)(12) of
         the Sarbanes-Oxley Act of 2002 (the "SARBANES-OXLEY ACT")) and (z) not
         in violation of the auditor independence requirements of the
         Sarbanes-Oxley Act.

                  (vi) The Company has been duly organized and is validly
         existing as a corporation in good standing under the laws of its
         jurisdiction of incorporation. The Company has full corporate power and
         authority to own its properties and conduct its business as currently
         being carried on and as described in the Registration Statement, the
         Time of Sale Disclosure Package and Prospectus, and is duly qualified
         to do business as a foreign corporation in good standing in each
         jurisdiction in which it owns or leases real property or in which the
         conduct of its business makes such qualification necessary and in which
         the failure to so qualify would reasonably be expected to have a
         material adverse effect upon the business, properties, operations,
         condition (financial or otherwise) or results of operations of the
         Company ("MATERIAL ADVERSE EFFECT").


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                  (vii) Except as contemplated in the Time of Sale Disclosure
         Package and in the Prospectus, subsequent to the respective dates as of
         which information is given in the Time of Sale Disclosure Package, the
         Company has not incurred any material liabilities or obligations,
         direct or contingent, or entered into any material transactions, or
         declared or paid any dividends or made any distribution of any kind
         with respect to its capital stock; and there has not been any change in
         the capital stock (other than a change in the number of outstanding
         shares of Common Stock due to the issuance of shares upon the exercise
         of outstanding options or warrants or those granted in compliance with
         this Section 2(a)(vii)), or any material change in the short-term or
         long-term debt, or any issuance of options, warrants, convertible
         securities or other rights to purchase the capital stock (other than
         grants of stock options under the Company's stock option plans existing
         on the date hereof or the Company's 2006 Stock Plan), of the Company,
         or any material adverse change in the general affairs, condition
         (financial or otherwise), business, property, operations or results of
         operations of the Company, taken as a whole ("MATERIAL ADVERSE CHANGE")
         or any development involving a prospective Material Adverse Change.

                  (viii) Except as set forth in the Registration Statement, in
         the Time of Sale Disclosure Package and in the Prospectus, there is not
         pending or, to the knowledge of the Company, threatened in writing, any
         action, suit or proceeding to which the Company is a party or of which
         any material property or assets of the Company is the subject before or
         by any court or governmental agency, authority or body, or any
         arbitrator, which, individually or in the aggregate, would reasonably
         be expected to result in any Material Adverse Change.

                  (ix) There are no statutes, regulations, contracts or
         documents that are required to be described in the Registration
         Statement, in the Time of Sale Disclosure Package and in the Prospectus
         or be filed as exhibits to the Registration Statement by the Act or by
         the Rules and Regulations that have not been so described or filed.

                  (x) This Agreement has been duly authorized, executed and
         delivered by the Company, and constitutes a valid, legal and binding
         obligation of the Company, enforceable in accordance with its terms,
         except as rights to indemnity hereunder may be limited by federal or
         state securities laws and except as such enforceability may be limited
         by bankruptcy, insolvency, reorganization or similar laws affecting the
         rights of creditors generally and subject to general principles of
         equity. The execution, delivery and performance of this Agreement and
         the consummation of the transactions herein contemplated will not
         result in a breach or violation of any of the terms and provisions of,
         or constitute a default under, any statute applicable to the Company,
         any material agreement or instrument to which the Company is a party or
         by which it is bound or to which any of its material property is
         subject, the Company's charter or by-laws, or any order, rule,
         regulation or decree of any court or governmental agency or body having
         jurisdiction over the Company or any of its material properties; no
         consent, approval, authorization or order of, or filing with, any court
         or governmental agency or body is required for the execution, delivery
         and performance of this Agreement or for the


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         consummation of the transactions contemplated hereby, including the
         issuance or sale of the Securities by the Company, except such as may
         be required under the Act or state securities or blue sky laws; and the
         Company has full power and authority to enter into this Agreement and
         to authorize, issue and sell the Securities as contemplated by this
         Agreement.

                  (xi) All of the issued and outstanding shares of capital stock
         of the Company, including the outstanding shares of Common Stock, are
         duly authorized and validly issued, fully paid and nonassessable, have
         been issued in compliance with all federal and state securities laws,
         were not issued in violation of or subject to any preemptive rights or
         other rights to subscribe for or purchase securities that have not been
         waived in writing, and the holders thereof are not subject to personal
         liability by reason of being such holders; the Securities which may be
         sold hereunder by the Company have been duly authorized and, when
         issued, delivered and paid for in accordance with the terms of this
         Agreement, will have been validly issued and will be fully paid and
         nonassessable, and the holders thereof will not be subject to personal
         liability by reason of being such holders; and the capital stock of the
         Company, including the Common Stock, conforms to the description
         thereof in the Registration Statement, in the Time of Sale Disclosure
         Package and in the Prospectus. Except as otherwise stated in the
         Registration Statement, in the Time of Sale Disclosure Package and in
         the Prospectus, there are no preemptive rights or other rights to
         subscribe for or to purchase, or any restriction upon the voting or
         transfer of, any shares of Common Stock pursuant to the Company's
         charter, by-laws or any agreement or other instrument to which the
         Company is a party or by which the Company is bound. Except as
         otherwise stated in the Registration Statement, in the Time of Sale
         Disclosure Package and in the Prospectus, neither the filing of the
         Registration Statement nor the offering or sale of the Securities as
         contemplated by this Agreement gives rise to any rights for or relating
         to the registration of any shares of Common Stock or other securities
         of the Company that have not been waived in writing. Except as
         described in the Registration Statement, in the Time of Sale Disclosure
         Package and in the Prospectus, there are no options, warrants,
         agreements, contracts or other rights in existence to purchase or
         acquire from the Company any shares of the capital stock of the
         Company. The Company has an authorized and outstanding capitalization
         as set forth in the Registration Statement, in the Time of Sale
         Disclosure Package and in the Prospectus.

                  (xii) The Company holds, and is operating in compliance in all
         material respects with, all material franchises, grants,
         authorizations, licenses, permits, easements, consents, certificates
         and orders of any governmental or self-regulatory body required for the
         conduct of its business and all such franchises, grants,
         authorizations, licenses, permits, easements, consents, certifications
         and orders are valid and in full force and effect; and the Company is
         in compliance in all material respects with all applicable federal,
         state, local and foreign laws, regulations, orders and decrees.

                  (xiii) The Company has good and marketable title to all
         property (whether real or personal) described in the Registration
         Statement, in the Time of Sale


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         Disclosure Package and in the Prospectus as being owned by it, in each
         case free and clear of all material liens, claims, security interests,
         other encumbrances or defects except such as are described in the
         Registration Statement, in the Time of Sale Disclosure Package and in
         the Prospectus. The property held under lease by the Company is held by
         it under valid, subsisting and enforceable leases with only such
         exceptions with respect to any particular lease as do not interfere in
         any material respect with the conduct of the business of the Company.

                  (xiv) The Company owns or possesses the right to use all
         patents, patent applications, trademarks, service marks, tradenames,
         trademark applications, service mark applications, copyrights,
         licenses, inventions, know-how, trade secrets and other intellectual
         property rights (collectively, the "Intellectual Property") necessary
         for the conduct of the business of the Company as currently carried on
         and as described in the Registration Statement, in the Time of Sale
         Disclosure Package and in the Prospectus, free and clear of any
         security interests, claims, liens or other encumbrances. The Company
         has not received notice of infringement of or conflict with asserted
         rights of others with respect to any Intellectual Property rights
         (including any claim that the Company must license or refrain from
         using any Intellectual Property of any third party). The use of the
         Intellectual Property in connection with the current and proposed
         business and operations of the Company does not and will not infringe
         on the rights of others or require the payment of license fees for any
         Intellectual Property of a third party material to the business or
         prospects of the Company. All material patents are listed on
         schedules to the opinions of intellectual property counsel attached as
         Exhibits B-1 and B-2.

                  (xv) The Company is not in violation of its charter or by-laws
         or in breach of or otherwise in default, and no event has occurred
         which, with notice or lapse of time or both, would constitute such a
         default in the performance of any material obligation, agreement or
         condition contained in any bond, debenture, note, indenture, loan
         agreement or any other material contract, lease or other instrument to
         which it is subject or by which it may be bound, or to which any of the
         material property or assets of the Company is subject, except as would
         not have a Material Adverse Effect.

                  (xvi) The Company has timely filed all federal, state, local
         and foreign income and franchise tax returns required to be filed and
         is not in default in the payment of any taxes which were payable
         pursuant to said returns or any assessments with respect thereto, other
         than any which the Company is contesting in good faith.

                  (xvii) The Company has not distributed and will not distribute
         any prospectus or other offering material in connection with the
         offering and sale of the Securities other than any Preliminary
         Prospectus, the Time of Sale Disclosure Package or the Prospectus or
         other materials permitted by the Act to be distributed by the Company;
         PROVIDED, HOWEVER, that, except as set forth on Schedule II, the
         Company has not made and will not make any offer relating to the
         Securities that would constitute a "free writing prospectus" as defined
         in Rule 405 under the Act, except in accordance with the provisions of
         Section 4(a)(xix) of this Agreement.


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                  (xviii) The Securities have been approved for listing on the
         Nasdaq National Market upon official notice of issuance and, on the
         date the Registration Statement became or becomes effective, the
         Company's Registration Statement on Form 8-A or other applicable form
         under the Securities Exchange Act of 1934, as amended (the "EXCHANGE
         ACT"), became or will become effective.

                  (xix) Except as disclosed in the Registration Statement, the
         Time of Sale Disclosure Package or the Prospectus, the Company,
         directly or indirectly, owns no capital stock or other equity or
         ownership or proprietary interest in any corporation, partnership,
         association, trust or other entity.

                  (xx) The Company's board of directors has validly appointed an
         audit committee whose composition satisfies the applicable requirements
         of Rule 4350(d)(2) of the Rules of the NASD (the "NASD Rules") and the
         Company's board of directors and/or the audit committee has adopted a
         charter that satisfies the requirements of Rule 4350(d)(1) of the NASD
         Rules. Neither the Company's board of directors, nor the audit
         committee has been informed, nor is any director of the Company aware,
         of (A) any significant deficiencies in the design or operation of the
         Company's internal controls which could adversely affect the Company's
         ability to record, process, summarize and report financial data or any
         material weakness in the Company's internal controls; or (B) any fraud,
         whether or not material, that involves management or other employees of
         the Company who have a significant role in the Company's internal
         controls.

                  (xxi) 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
         Time of Sale Disclosure Package and the Prospectus which is not so
         described. The Company has not, directly or indirectly, extended or
         maintained credit, or arranged for the extension of credit, or renewed
         an extension of credit, in the form of a personal loan to or for any of
         its directors or executive officers in violation of applicable laws,
         including Section 402 of the Sarbanes-Oxley Act.

                  (xxii) The Company maintains a system of internal accounting
         controls sufficient to provide reasonable assurances that (i)
         transactions are executed in accordance with management's general or
         specific authorization; (ii) transactions are recorded as necessary to
         permit preparation of financial statements in conformity with generally
         accepted accounting principles and to maintain accountability for
         assets; (iii) access to assets is permitted only in accordance with
         management's general or specific authorization; and (iv) the recorded
         accountability for assets is compared with existing assets at
         reasonable intervals and appropriate action is taken with respect to
         any differences. Since the end of the latest audited fiscal year, there
         has been no change in the Company's internal control over financial
         reporting (whether or not remediated) that has materially affected, or
         is reasonably likely to materially affect, the Company's internal
         control over financial reporting.


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                  (xxiii) Except as disclosed in the Registration Statement, the
         Time of Disclosure Package or the Prospectus, the Company (A) is in
         compliance, in all material respects, with any and all applicable
         federal, state, local and foreign laws, rules, regulations, decisions
         and orders relating to the protection of human health and safety, the
         environment or hazardous or toxic substances or wastes, pollutants or
         contaminants (collectively, "Environmental Laws"); (B) has received and
         is in compliance with all permits, licenses or other approvals required
         of it under applicable Environmental Laws to conduct its business; and
         (C) has not received notice of any actual or potential liability for
         the investigation or remediation of any disposal or release of
         hazardous or toxic substances or wastes, pollutants or contaminants,
         except in any such case for any such failure to comply, or failure to
         receive required permits, licenses or approvals, or liability as would
         not, individually or in the aggregate, reasonably be expected to result
         in a Material Adverse Change.

                  (xxiv) The Company (A) is in compliance, in all material
         respects, with any and all applicable foreign, federal, state and local
         laws, rules, regulations, treaties, statutes and codes promulgated by
         any and all governmental authorities (including pursuant to the
         Occupational Health and Safety Act) relating to the protection of human
         health and safety in the workplace ("Occupational Laws"); (B) has
         received all material permits, licenses or other approvals required of
         it under applicable Occupational Laws to conduct its business as
         currently conducted; and (C) is in compliance, in all material
         respects, with all terms and conditions of such permit, license or
         approval. No material action, proceeding, revocation proceeding, writ,
         injunction or claim is pending or, to the Company's knowledge,
         threatened against the Company relating to Occupational Laws and the
         Company does not have knowledge of any facts, circumstances or
         developments relating to its operations or cost accounting practices
         that could reasonably be expected to form the basis for or give rise to
         such actions, suits, investigations or proceedings.

                  (xxv) Each employee benefit plan, within the meaning of
         Section 3(3) of the Employee Retirement Income Security Act of 1974, as
         amended ("ERISA"), that is maintained, administered or contributed to
         by the Company or any of its affiliates for employees or former
         employees of the Company and its affiliates has been maintained in
         material compliance with its terms and the requirements of any
         applicable statutes, orders, rules and regulations, including but not
         limited to, ERISA and the Internal Revenue Code of 1986, as amended
         (the "Code"). No material prohibited transaction, within the meaning of
         Section 406 of ERISA or Section 4975 of the Code, has occurred with
         respect to any such plan excluding transactions effected pursuant to a
         statutory or administrative exemption; and for each such plan that is
         subject to the funding rules of Section 412 of the Code or Section 302
         of ERISA, no "accumulated funding deficiency" as defined in Section 412
         of the Code has been incurred, whether or not waived, and the fair
         market value of the assets of each such plan (excluding for these
         purposes accrued but unpaid contributions) exceeds the present value of
         all benefits accrued under such plan determined using reasonable
         actuarial assumptions.


                                      -10-
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                  (xxvi) Except as set forth in the Registration Statement, the
         Time of Sale Disclosure Package and the Prospectus and except for
         contract manufacturers and similar parties engaged by the Company, the
         Company has not granted material rights to develop, manufacture,
         produce, assemble, distribute, license, market or sell its products to
         any other person and is not bound by any agreement that materially
         affects the Company's exclusive right to develop, manufacture, produce,
         assemble, distribute, license, market or sell its products.

                  (xxvii) Nothing has come to the attention of the Company that
         has caused the Company to believe that the statistical and
         market-related data included in the Registration Statement, the Time of
         Sale Disclosure Package and the Prospectus is not based on or derived
         from sources that are reliable and accurate in all material respects.

                  (xxviii) Other than as contemplated by this Agreement, the
         Company has not incurred any liability for any finder's or broker's fee
         or agent's commission in connection with the execution and delivery of
         this Agreement or the consummation of the transactions contemplated
         hereby.

                  (xxix) The Company carries, or is covered by, insurance in
         such amounts and covering such risks as is adequate for the conduct of
         its business and the value of its properties and as is customary for
         companies engaged in similar businesses in similar industries.

                  (xxx) Except with notice to the Representatives and compliance
         with applicable laws, none of the Directed Stock (as defined below)
         distributed in connection with the Directed Stock Program (as defined
         below) will be offered or sold outside of the United States.

                  (xxxi) Neither the Company nor, to the knowledge of the
         Company, any director, officer, agent, employee or other person
         associated with or acting on behalf of the Company has (A) used any
         corporate funds for any unlawful contribution, gift, entertainment or
         other unlawful expense relating to political activity; (B) made any
         direct or indirect unlawful payment to any foreign or domestic
         government official or employee from corporate funds; (C) violated or
         is in violation of any provision of the Foreign Corrupt Practices Act
         of 1977 on behalf of the Company or using corporate funds; or (D) made
         any bribe, rebate, payoff, influence payment, kickback or other
         unlawful payment on behalf of the Company or using corporate funds.

                  (xxxii) The Company is not and, after giving effect to the
         offering and sale of the Securities, will not be an "investment
         company," as such term is defined in the Investment Company Act of
         1940, as amended.

                  (xxxiii) The Company is in compliance with all applicable
         provisions of the Sarbanes Oxley Act and the rules and regulations of
         the Commission thereunder applicable to the Company.


                                      -11-
<Page>


                  (xxxiv) The Company acknowledges and agrees that: (A) the
         Representatives have been retained solely to act as an underwriter in
         connection with the sale of the Securities and that no fiduciary,
         advisory or agency relationship between the Company and the
         Representatives has been created in respect to any of the transactions
         contemplated by this Agreement, irrespective of whether the
         Representatives have advised or are advising the Company on other
         matters; (B) the price and other terms of the Securities set forth in
         this Agreement were established by the Company following discussions
         and arms-length negotiations with the Representatives and the Company
         are capable of evaluating and understanding and understand and accept
         the terms, risks and conditions of the transaction contemplated by this
         Agreement; (C) it has been advised that the Representatives and their
         affiliates are engaged in a broad range of transactions which may
         involve interests that differ from those of the Company and that the
         Representatives have no obligation to disclose such interests and
         transactions to the Company by virtue of any fiduciary, advisory or
         agency relationship; (D) it has been advised that the Representatives
         are acting, in respect of the transactions contemplated by this
         Agreement, solely for the benefit of the Representatives and the other
         Underwriters, and not on behalf of the Company; and (E) it waives, to
         the fullest extent permitted by law, any claims it may have against the
         Representatives for breach of fiduciary duty or alleged breach of
         fiduciary duty in respect of any of the transactions contemplated by
         this Agreement and agrees that the Representatives shall have no
         liability (whether direct or indirect) to the Company in respect of
         such a fiduciary duty claim on behalf of or in right of the Company,
         including stockholders, employees or creditors of the Company.

                  (xxxv) The Company has established and maintains disclosure
         controls and procedures (as defined in Rules 13a-15 and 15d-14 under
         the Exchange Act) and such controls and procedures are effective in
         ensuring that material information relating to the Company is made
         known to the principal executive officer and the principal financial
         officer. The Company has utilized such disclosure controls and
         procedures in preparing and evaluating the disclosures in the
         Registration Statement, in the Time of Sale Disclosure Package and in
         the Prospectus.

            (b) Any certificate signed by any officer of the Company and
delivered to you or to counsel for the Underwriters in connection with the
transactions contemplated by this Agreement shall be deemed a representation and
warranty by the Company to each Underwriter as to the matters covered thereby.

         3. PURCHASE, SALE AND DELIVERY OF SECURITIES.

            (a) On the basis of the representations, warranties and agreements
herein contained, but subject to the terms and conditions herein set forth, the
Company agrees to issue and sell [ ] Firm Shares to the several Underwriters,
and each Underwriter agrees, severally and not jointly, to purchase from the
Company the number of Firm Shares set forth opposite the name of such
Underwriter in Schedule I hereto. The purchase price for each Firm Share shall


                                      -12-
<Page>


be $ per share. In making this Agreement, each Underwriter is contracting
severally and not jointly; except as provided in paragraph (c) of this Section 3
and in Section 8 hereof, the agreement of each Underwriter is to purchase only
the respective number of Firm Shares specified in Schedule I.

            It is understood that [_____] shares of the Firm Shares ("DIRECTED
STOCK") will initially be reserved by the Underwriters for offer and sale to
employees and persons having relationships with the Company or its employees
("DIRECTED STOCK PARTICIPANTS") upon the terms and conditions set forth in the
Prospectus and in accordance with the rules and regulations of the National
Association of Securities Dealers ("DIRECTED STOCK PROGRAM"). Under no
circumstance will the Representatives or any Underwriter be liable to the
Company or to any Directed Stock Participant for any action taken or omitted to
be taken in good faith in connection with such Directed Stock Program. To the
extent that any shares of Directed Stock are not affirmatively reconfirmed for
purchase by any Directed Stock Participant on or immediately after the date of
this Agreement, such Directed Stock may be offered to the public as part of the
public offering contemplated hereby. The Company agrees to pay all fees and
disbursements incurred by the Underwriters in connection with the Directed Stock
Program, including counsel fees and any stamp duties or other taxes incurred by
the Underwriters in connection with the Directed Stock Program.

            The Firm Shares will be delivered by the Company and the Custodian
to you for the accounts of the several Underwriters against payment of the
purchase price therefor by wire transfer of same day FUNDS payable to the order
of the Company and the Custodian, as appropriate, at the offices of Latham &
Watkins LLP, 885 Third Avenue, New York, New York 10022, or such other location
as may be mutually acceptable, at [_____] a.m. Eastern time on the third (or if
the Securities are priced, as contemplated by Rule 15c6-1(c) under the Exchange
Act, after [_____] p.m. Eastern time, the fourth) full business day following
the date hereof, or at such other time and date as you and the Company determine
pursuant to Rule 15c6-1(a) under the Exchange Act, such time and date of
delivery being herein referred to as the "First Closing Date." If the
Representatives so elect, delivery of the Firm Shares may be made by credit
through full fast transfer to the accounts at The Depository Trust Company
designated by the Representatives. Certificates representing the Firm Shares, in
definitive form and in such denominations and registered in such names as you
may request upon at least two business days' prior notice to the Company and the
Custodian, will be made available for checking and packaging not later than
[_____] a.m., Eastern time, on the business day next preceding the First Closing
Date at the offices of Latham & Watkins LLP, 885 Third Avenue, New York, New
York 10022, or such other location as may be mutually acceptable.

            (b) On the basis of the representations, warranties and agreements
herein contained, but subject to the terms and conditions herein set forth, the
Company, with respect to [_____] of the Option Shares, hereby grants to the
several Underwriters an option to purchase all or any portion of the Option
Shares at the same purchase price as the Firm Shares, for use solely in covering
any over-allotments made by the Underwriters in the sale and distribution of the
Firm Shares. The option granted hereunder may be exercised in whole or in part
at any time (but not more than once) within 30 days after the effective date of
this Agreement upon notice


                                      -13-
<Page>


(confirmed in writing) by the Representatives to the Company and to the
Attorneys-in-Fact setting forth the aggregate number of Option Shares as to
which the several Underwriters are exercising the option, the names and
denominations in which the certificates for the Option Shares are to be
registered and the date and time, as determined by you, when the Option Shares
are to be delivered, such time and date being herein referred to as the "Second
Closing" and "Second Closing Date", respectively; provided, however, that the
Second Closing Date shall not be earlier than the First Closing Date nor earlier
than the second business day after the date on which the option shall have been
exercised. If the option is exercised, the obligation of each Underwriter shall
be to purchase from the Company up to an aggregate of [ ] Option Shares. The
number of Option Shares to be purchased by each Underwriter shall be the same
percentage of the total number of Option Shares to be purchased by the several
Underwriters as the number of Firm Shares to be purchased by such Underwriter is
of the total number of Firm Shares to be purchased by the several Underwriters,
as adjusted by the Representatives in such manner as the Representatives deem
advisable to avoid fractional shares. No Option Shares shall be sold and
delivered unless the Firm Shares previously have been, or simultaneously are,
sold and delivered.

            The Option Shares will be delivered by the Custodian and the
Company, as appropriate, to you for the accounts of the several Underwriters
against payment of the purchase price therefor by wire transfer of same day
funds payable to the order of the Custodian or the Company, as appropriate, at
the offices of Latham & Watkins LLP, 885 Third Avenue, New York, New York 10022,
or such other location as may be mutually acceptable at [_____] a.m., Eastern
time, on the Second Closing Date. If the Representatives so elect, delivery of
the Option Shares may be made by credit through full fast transfer to the
accounts at The Depository Trust Company designated by the Representatives.
Certificates representing the Option Shares in definitive form and in such
denominations and registered in such names as you have set forth in your notice
of option exercise, will be made available for checking and packaging not later
than [_____] a.m., Eastern time, on the business day next preceding the Second
Closing Date at the office of Latham & Watkins LLP, 885 Third Avenue, New York,
New York 10022, or such other location as may be mutually acceptable.

            (c) It is understood that you, individually and not as
Representatives of the several Underwriters, may (but shall not be obligated to)
make payment to the Company, on behalf of any Underwriter for the Securities to
be purchased by such Underwriter. Any such payment by you shall not relieve any
such Underwriter of any of its obligations hereunder. Nothing herein contained
shall constitute any of the Underwriters an unincorporated association or
partner with the Company.

         4. COVENANTS.

            (a) The Company covenants and agrees with the several Underwriters
as follows:

                  (i) If the Registration Statement has not already been
         declared effective by the Commission, the Company will use its
         reasonable best efforts to cause


                                      -14-
<Page>


         the Registration Statement and any post-effective amendments thereto to
         become effective as promptly as possible; the Company will notify you
         promptly of the time when the Registration Statement or any
         post-effective amendment to the Registration Statement has become
         effective or any supplement to the Prospectus has been filed and of any
         request by the Commission for any amendment or supplement to the
         Registration Statement or Prospectus or additional information; if the
         Company has elected to rely on Rule 430A of the Rules and Regulations,
         the Company will prepare and file a Prospectus containing the
         information omitted therefrom pursuant to Rule 430A of the Rules and
         Regulations with the Commission within the time period required by, and
         otherwise in accordance with the provisions of, Rules 424(b) and 430A
         of the Rules and Regulations; if the Company has elected to rely upon
         Rule 462(b) of the Rules and Regulations to increase the size of the
         offering registered under the Act, the Company will prepare and file a
         registration statement with respect to such increase with the
         Commission within the time period required by, and otherwise in
         accordance with the provisions of, Rule 462(b); the Company will
         prepare and file with the Commission, promptly upon your request, any
         amendments or supplements to the Registration Statement or Prospectus
         that, in your opinion, may be necessary or advisable in connection with
         the distribution of the Securities by the Underwriters; and the Company
         will not file any amendment or supplement to the Registration Statement
         or Prospectus to which you shall reasonably object by notice to the
         Company after having been furnished a copy a reasonable time prior to
         the filing.

                  (ii) The Company will advise you, promptly after it shall
         receive notice or obtain knowledge thereof, of the issuance by the
         Commission of any stop order suspending the effectiveness of the
         Registration Statement, or any post-effective amendment thereto or
         preventing or suspending the use of any Preliminary Prospectus, the
         Time of Sale Disclosure Package, the Prospectus or any Issuer Free
         Writing Prospectus, of the suspension of the qualification of the
         Securities for offering or sale in any jurisdiction, or of the
         initiation or threatening of any proceeding for any such purpose; and
         the Company will promptly use its reasonable best efforts to prevent
         the issuance of any stop order or to obtain its withdrawal if such a
         stop order should be issued. Additionally, the Company agrees that it
         shall comply with the provisions of Rules 424(b) and 430A, as
         applicable, under the Act and will use its reasonable efforts to
         confirm that any filings made by the Company under Rule 424(b), Rule
         433 or Rule 462 were received in a timely manner by the Commission.

                  (iii) (A) Within the time during which a prospectus (or in
         lieu thereof the notice referred to in Rule 173(a)) relating to the
         Securities is required to be delivered under the Act, the Company will
         comply as far as it is able with all requirements imposed upon it by
         the Act, as now and hereafter amended, and by the Rules and
         Regulations, as from time to time in force, so far as necessary to
         permit the continuance of sales of or dealings in the Securities as
         contemplated by the provisions hereof, the Time of Sale Disclosure
         Package and the Prospectus. If during such period any event occurs as a
         result of which the Prospectus (or if the Prospectus is not yet
         available to prospective purchasers, the Time of Sale Disclosure
         Package) would include an untrue


                                      -15-
<Page>


         statement of a material fact or omit to state a material fact necessary
         to make the statements therein, in the light of the circumstances then
         existing, not misleading, or if during such period it is necessary to
         amend the Registration Statement or supplement the Prospectus (or if
         the Prospectus is not yet available to prospective investors, the Time
         of Sale Disclosure Package) to comply with the Act, the Company will
         promptly notify you and will amend the Registration Statement or
         supplement the Prospectus (or, if the Prospectus is not yet available
         to prospective purchasers, the Time of Sale Disclosure Package) (at the
         expense of the Company) so as to correct such statement or omission or
         effect such compliance.

                  (B) If at any time following issuance of an Issuer Free
         Writing Prospectus there occurred or occurs an event or development as
         a result of which such Issuer Free Writing Prospectus conflicted or
         would conflict with the information contained in the Registration
         Statement, any Statutory Prospectus or the Prospectus relating to the
         Securities or included or would include an untrue statement of a
         material fact or omitted or would omit to state a material fact
         necessary in order to make the statements therein, in the light of the
         circumstances prevailing at that subsequent time, not misleading, the
         Company has promptly notified or promptly will notify the
         Representatives and has promptly amended or will promptly amend or
         supplement, at its own expense, such Issuer Free Writing Prospectus to
         eliminate or correct such conflict, untrue statement or omission.

                  (iv) The Company shall take or cause to be taken all necessary
         action to qualify the Securities for sale under the securities laws of
         such jurisdictions as you reasonably designate or as is necessary to
         effect the distribution of the Directed Stock and to continue such
         qualifications in effect so long as required for the distribution of
         the Securities, except that the Company shall not be required in
         connection therewith to qualify as a foreign corporation or to execute
         a general consent to service of process in any state.

                  (v) The Company will furnish to the Underwriters and counsel
         for the Underwriters copies of the Registration Statement (three of
         which include all consents and exhibits filed therewith), each
         Preliminary Prospectus, the Time of Sale Disclosure Package, the
         Prospectus, any Issuer Free Writing Prospectus and all amendments and
         supplements to such documents, in each case as soon as available and in
         such quantities as you may from time to time reasonably request.

                  (vi) During a period of two years commencing with the date
         hereof, the Company will furnish to the Representatives, and to each
         Underwriter who may so request in writing, copies of all periodic and
         current reports furnished to the stockholders of the Company and all
         information, documents and reports filed with the Commission, the
         National Association of Securities Dealers, Inc., Nasdaq or any
         securities exchange (other than any such information, documents and
         reports that are filed with the Commission electronically via EDGAR or
         any successor system).


                                      -16-
<Page>


                  (vii) The Company will make generally available to its
         security holders as soon as practicable, but in any event not later
         than 15 months after the end of the Company's current fiscal quarter,
         an earnings statement (which need not be audited) covering a 12-month
         period beginning after the effective date of the Registration Statement
         that shall satisfy the provisions of Section 11(a) of the Act and Rule
         158 of the Rules and Regulations.

                  (viii) The Company, whether or not the transactions
         contemplated hereunder are consummated or this Agreement is prevented
         from becoming effective under the provisions of Section 9(a) hereof or
         is terminated, will pay or cause to be paid (A) all expenses (including
         transfer taxes allocated to the respective transferees) incurred in
         connection with the delivery to the Underwriters of the Securities, (B)
         all expenses and fees (including, without limitation, fees and expenses
         of the Company's accountants and counsel but, except as otherwise
         provided below, not including fees of the Underwriters' counsel) in
         connection with the preparation, printing, filing, delivery, and
         shipping of the Registration Statement (including the financial
         statements therein and all amendments, schedules, and exhibits
         thereto), the Securities, each Preliminary Prospectus, the Time of Sale
         Disclosure Package, the Prospectus, any Issuer Free Writing Prospectus
         and any amendment thereof or supplement thereto, and the printing,
         delivery, and shipping of this Agreement and other underwriting
         documents, including Blue Sky Memoranda (covering the states and other
         applicable jurisdictions), (C) all filing fees and fees and
         disbursements of the Underwriters' counsel, not to exceed, in the
         aggregate, $12,500, incurred in connection with the qualification of
         the Securities for offering and sale by the Underwriters or by dealers
         under the securities or blue sky laws of the states and other
         jurisdictions which you shall designate or are necessary to distribute
         the Directed Stock, (D) the fees and expenses of any transfer agent or
         registrar, (E) the filing fees and fees and disbursements of the
         Underwriters' counsel incident to any required review by the National
         Association of Securities Dealers, Inc. of the terms of the sale of the
         Securities, (F) listing fees, if any, and (G) all other costs and
         expenses incident to the performance of its obligations hereunder that
         are not otherwise specifically provided for herein; provided, however,
         that the Underwriters shall bear the cost of travel and lodging for the
         Underwriters in connection with the investor presentations on any "road
         show" undertaken in connection with the marketing of the Securities,
         stock transfer taxes on any resale of the Securities by them and any
         advertising expenses connected with any offers they may make. If the
         sale of the Securities provided for herein is not consummated by reason
         of action by the Company pursuant to Section 9(a) hereof which prevents
         this Agreement from becoming effective, or by reason of any failure,
         refusal or inability on the part of the Company to perform any
         agreement on its part to be performed, or because any other condition
         of the Underwriters' obligations hereunder required to be fulfilled by
         the Company is not fulfilled, the Company will reimburse the several
         Underwriters for all out-of-pocket disbursements (including reasonable
         fees and disbursements of counsel) incurred by the Underwriters in
         connection with their investigation, preparing to market and marketing
         the Securities or in contemplation of performing their obligations
         hereunder. The


                                      -17-
<Page>


         Company shall not in any event be liable to any of the Underwriters for
         loss of anticipated profits from the transactions covered by this
         Agreement.

                  (ix) The Company will apply the net proceeds from the sale of
         the Securities to be sold by it hereunder for the purposes set forth in
         the Time of Sale Disclosure Package and in the Prospectus and will file
         such reports with the Commission with respect to the sale of the
         Securities and the application of the proceeds therefrom as may be
         required in accordance with Rule 463 of the Rules and Regulations.

                  (x) Except as set forth in the Registration Statement, the
         Time of Sale Disclosure Package and the Prospectus, the Company will
         not, without the prior written consent of Piper Jaffray & Co., from the
         date of execution of this Agreement and continuing to and including the
         date 180 days after the date of the Prospectus (the "LOCK-UP PERIOD")
         offer for sale; sell, contract to sell, pledge, grant any option for
         the sale of, enter into any transaction which is designed to, or might
         reasonably be expected to, result in the disposition (whether by actual
         disposition or effective economic disposition due to cash settlement or
         otherwise) by the Company or any affiliate, or otherwise issue or
         dispose of, directly or indirectly (or publicly disclose the intention
         to make any such offer, sale, pledge, grant, issuance or other
         disposition), any Common Stock or any securities convertible into or
         exchangeable for, or any options or rights to purchase or acquire,
         Common Stock, except (i) to the Underwriters pursuant to this
         Agreement, (ii) to directors, employees and consultants of the Company
         under the Company's stock option plans existing on the date hereof or
         the Company's 2006 Stock Plan and (iii) upon the exercise or conversion
         of securities outstanding on the date hereof or granted in compliance
         with clause (ii) above. The Company agrees not to accelerate the
         vesting of any option or warrant or the lapse of any repurchase right
         prior to the expiration of the Lock-Up Period. If (1) during the period
         that begins on the date that is 18 calendar days before the last day of
         the Lock-Up Period and ends on the last day of the Lock-Up Period, (a)
         the Company issues an earnings release, (b) the Company publicly
         announces material news or (c) a material event relating to the Company
         occurs; or (2) prior to the expiration of the Lock-Up Period, the
         Company announces that it will release earnings results during the
         16-day period beginning on the last day of the Lock-Up Period, then the
         restrictions in this Agreement, unless otherwise waived by Piper
         Jaffray & Co. in writing, shall continue to apply until the expiration
         of the date that is 18 calendar days after the date on which (a) the
         Company issues the earnings release, (b) the Company publicly announces
         material news or (c) a material event relating to the Company occurs.
         The Company will provide the Representatives, any co-managers and each
         shareholder subject to the Lock-Up Agreement (as defined below) with
         prior notice of any such announcement that gives rise to the extension
         of the Lock-Up Period.

                  (xi) The Company has caused to be delivered to you prior to
         the date of this Agreement a letter from each of the Company's
         directors and officers and certain of its shareholders stating that
         such person agrees that he or she will not, without your prior written
         consent, offer for sale, sell, contract to sell or otherwise dispose
         of, as set


                                      -18-
<Page>


         forth in such letter, any shares of Common Stock or rights to purchase
         Common Stock, except to the Underwriters pursuant to this Agreement,
         for a period commencing on the date of such letter and ending the
         earlier of (a) 180 days after the date hereof and (b) December 31, 2006
         if on such date this Agreement has not been executed (the "LOCK-UP
         AGREEMENT"). The Company will enforce the terms of each Lock-Up
         Agreement and issue stop-transfer instructions to the transfer agent
         for the Common Stock with respect to any transaction or contemplated
         transaction that would constitute a breach of or default under the
         applicable Lock-Up Agreement.

                  (xii) The Company has not taken and will not take, directly or
         indirectly, any action designed to or which might reasonably be
         expected to cause or result in, or which has constituted, the
         stabilization or manipulation of the price of any security of the
         Company to facilitate the sale or resale of the Securities, and has not
         effected any sales of Common Stock which are required to be disclosed
         in response to Item 701 of Regulation S-K under the Act which have not
         been so disclosed in the Registration Statement.

                  (xiii) The Company will not incur any liability for any
         finder's or broker's fee or agent's commission in connection with the
         execution and delivery of this Agreement or the consummation of the
         transactions contemplated hereby.

                  (xiv) The Company will comply with all applicable securities
         and other applicable laws, rules and regulations in each foreign
         jurisdiction in which Directed Stock is offered in connection with the
         Directed Stock Program.

                  (xv) In connection with the Directed Stock Program to ensure
         that the Directed Stock will be restricted to the extent required by
         the National Association of Securities Dealers or the rules of such
         association from sale, transfer, assignment, pledge or hypothecation
         for a period of three months following the date of the effectiveness of
         the Registration Statement, the Company will direct the transfer agent
         to place stop-transfer restrictions upon such securities for such
         period of time. Should the Company release, or seek to release, from
         such restrictions any of the Directed Stock, the Company agrees to
         reimburse the Underwriters for any reasonable expense (including,
         without limitation, legal expenses) they incur with such release.

                  (xvi) The Company will file with the Commission such periodic
         and current reports as required by the rules and regulations of the
         Commission under the Exchange Act.

                  (xvii) The Company will establish, within the timer prescribed
         by the rules of the Commission and, after such time, will maintain
         controls and other procedures required by Sections 302 and 906 of the
         Sarbanes-Oxley Act and the applicable regulations thereunder, that are
         designed to ensure that information required to be disclosed by the
         Company in the reports that it files or submits under the Exchange Act
         is recorded, processed, summarized and reported within the time


                                      -19-
<Page>


         periods specified in the Commission's rules and forms, including
         without limitation, controls and procedures designed to ensure that
         information required to be disclosed by the Company in the reports that
         it files or submits under the Exchange Act is accumulated and
         communicated to the Company's management, including its principal
         executive officer and its principal financial officer, or persons
         performing similar functions, as appropriate to allow timely decisions
         regarding required disclosure, to ensure that material information
         relating to Company is made known to them by others within the Company.

                  (xviii) The Company will comply with all effective applicable
         provisions of the Sarbanes-Oxley Act.

                  (xix) The Company represents and agrees that, unless it
         obtains the prior written consent of Piper Jaffray & Co., and each
         Underwriter severally represents and agrees that, unless it obtains the
         prior written consent of the Company and Piper Jaffray & Co., it has
         not made and will not make any offer relating to the Securities that
         would constitute an "issuer free writing prospectus," as defined in
         Rule 433 under the Securities Act, or that would otherwise constitute a
         "free writing prospectus," as defined in Rule 405 under the Securities
         Act, required to be filed with the Commission; provided that the prior
         written consent of the parties hereto shall be deemed to have been
         given in respect of the free writing prospectuses included in Schedule
         II. Any such free writing prospectus consented to by the Company and
         Piper Jaffray & Co. is hereinafter referred to as a "PERMITTED FREE
         WRITING PROSPECTUS." The Company represents that it has treated or
         agrees that it will treat each Permitted Free Writing Prospectus as an
         "issuer free writing prospectus," as defined in Rule 433, and has
         complied and will comply with the requirements of Rule 433 applicable
         to any Permitted Free Writing Prospectus, including timely Commission
         filing where required, legending and record keeping. The Company
         represents that it has satisfied and agrees that it will satisfy the
         conditions in Rule 433 to avoid a requirement to file with the
         Commission any electronic road show.

         5. CONDITIONS OF UNDERWRITERS' OBLIGATIONS. The obligations of the
several Underwriters hereunder are subject to the accuracy, as of the date
hereof and at each of the First Closing Date and the Second Closing Date (as if
made at such Closing Date), of and compliance with, in all material respects,
all representations, warranties and agreements of the Company contained herein,
to the performance by the Company of its obligations hereunder and to the
following additional conditions:

            (a) The Registration Statement shall have become effective not later
than 5:30 p.m., Eastern time, on the date of this Agreement, or such later time
and date as you, as Representatives of the several Underwriters, shall approve
and all filings required by Rules 424, 430A and 433 of the Rules and Regulations
shall have been timely made (without reliance on Rule 424(b)(8) or Rule 164(b));
no stop order suspending the effectiveness of the Registration Statement or any
part thereof or any amendment thereof, nor suspending or preventing the use of
the Time of Sale Disclosure Package, the Prospectus or any Issuer Free Writing
Prospectus


                                      -20-
<Page>


shall have been issued; no proceedings for the issuance of such an order shall
have been initiated or threatened; and any request of the Commission for
additional information (to be included in the Registration Statement, the Time
of Sale Disclosure Package, the Prospectus, any Issuer Free Writing Prospectus
or otherwise) shall have been complied with to your satisfaction.

            (b) No Underwriter shall have advised the Company that the
Registration Statement, the Time of sale Disclosure Package or the Prospectus,
or any amendment thereof or supplement thereto, or any Issuer Free Writing
Prospectus contains an untrue statement of fact which, in your opinion, is
material, or omits to state a fact which, in your opinion, is material and is
required to be stated therein or necessary to make the statements therein not
misleading.

            (c) Except as contemplated in the Time of Sale Disclosure Package
and in the Prospectus, subsequent to the respective dates as of which
information is given in the Time of Sale Disclosure Package, the Company shall
not have incurred any material liabilities or obligations, direct or contingent,
or entered into any material transactions, or declared or paid any dividends or
made any distribution of any kind with respect to its capital stock; and there
shall not have been any change in the capital stock (other than a change in the
number of outstanding shares of Common Stock due to the issuance of shares upon
the exercise of outstanding options or warrants), or any material change in the
short-term or long-term debt of the Company, or any issuance of options,
warrants, convertible securities or other rights to purchase the capital stock
of the Company (other than grants of stock options under the Company's stock
option plans existing on the date hereof or the Company's 2006 Stock Plan), or
any Material Adverse Change or any development involving a prospective Material
Adverse Change (whether or not arising in the ordinary course of business),
that, in your judgment, makes it impractical or inadvisable to offer or deliver
the Securities on the terms and in the manner contemplated in the Time of Sale
Disclosure Package and in the Prospectus.

            (d) On or after the Time of Sale (i) no downgrading shall have
occurred in the rating accorded the Company's debt securities or preferred stock
by any "nationally recognized statistical organization," as that term is defined
by the Commission for purposes of Rule 436(g)(2) under the Act, and (ii) no such
organization shall have publicly announced that it has under surveillance or
review, with possible negative implications, its rating of any of the Company's
debt securities or preferred stock;

            (e) On each Closing Date, there shall have been furnished to you, as
Representatives of the several Underwriters, the opinion of Goodwin Procter LLP,
counsel for the Company, dated such Closing Date and addressed to you, to in the
form set forth on Exhibit A. hereto

            (f) On each Closing Date, there shall have been furnished to you, as
Representatives of the several Underwriters, the opinion of each of Fish &
Richardson Pabst Patent Group LLP, special intellectual property counsel for
the Company, dated such Closing Date and addressed to you, in the forms set
forth on Exhibits B-1 and B-2 hereto.


                                      -21-
<Page>


            (g) On each Closing Date, there shall have been furnished to you, as
Representatives of the several Underwriters, such opinion or opinions from
Latham & Watkins LLP, counsel for the several Underwriters, dated such Closing
Date and addressed to you, with respect to such matters as you reasonably may
request, and such counsel shall have received such papers and information as
they request to enable them to pass upon such matters.

            (h) On each Closing Date you, as Representatives of the several
Underwriters, shall have received a letter of PricewaterhouseCoopers LLP, dated
such Closing Date and addressed to you, confirming that they are independent
public accountants within the meaning of the Act and are in compliance with the
applicable requirements relating to the qualifications of accountants under Rule
2-01 of Regulation S-X of the Commission, and stating, as of the date of such
letter (or, with respect to matters involving changes or developments since the
respective dates as of which specified financial information is given in the
Time of Sale Disclosure Package, as of a date not prior to the date hereof or
more than five days prior to the date of such letter), the conclusions and
findings of said firm with respect to the financial information and other
matters covered by its letter delivered to you concurrently with the execution
of this Agreement, and the effect of the letter so to be delivered on such
Closing Date shall be to confirm the conclusions and findings set forth in such
prior letter.

            (i) On each Closing Date, there shall have been furnished to you, as
Representatives of the Underwriters, a certificate, dated such Closing Date and
addressed to you, signed by the chief executive officer and by the chief
financial officer of the Company, to the effect that:

                  (i) The representations and warranties of the Company in this
         Agreement are true and correct, in all material respects, as if made at
         and as of such Closing Date, and the Company has complied with all the
         agreements and satisfied all the conditions on its part to be performed
         or satisfied at or prior to such Closing Date;

                  (ii) No stop order or other order suspending the effectiveness
         of the Registration Statement or any part thereof or any amendment
         thereof or the qualification of the Securities for offering or sale,
         nor suspending or preventing the use of the Time of Sale Disclosure
         Package, the Prospectus or any Issuer Free Writing Prospectus, has been
         issued, and no proceeding for that purpose has been instituted or, to
         the best of their knowledge, is contemplated by the Commission or any
         state or regulatory body; and

                  (iii) The signers of said certificate have carefully examined
         the Registration Statement, the Time of Sale Disclosure Package and the
         Prospectus, and any amendments thereof or supplements thereto, and (A)
         each part of the Registration Statement and the Prospectus, and any
         amendments thereof or supplements thereto contain, and contained when
         such part of the Registration Statement, or any amendment thereof,
         became effective, all statements and information required to be
         included therein, the Registration Statement, or any amendment thereof,
         does not contain and did not


                                      -22-
<Page>


         contain when such part of the Registration Statement, or any amendment
         thereof, became effective, 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 not misleading, and the
         Prospectus, as amended or supplemented, does not include and did not
         include as of its date or the time of first use within the meaning of
         the Rules and Regulations, any untrue statement of material fact or
         omit to state and did not omit to state as of its date or the time of
         first use within the meaning of the rules and Regulations a material
         fact necessary to make the statements therein, in light of the
         circumstances under which they were made, not misleading, (B) neither
         (1) the Time of Sale Disclosure Package nor (2) any individual Issuer
         Limited-Use Free Writing Prospectus, when considered together with the
         Time of Sale Disclosure Package, include, nor included as of the Time
         of Sale any untrue statement of a material fact or omits, or omitted as
         of the Time of Sale, 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, (C) since the Time of Sale there
         has occurred no event required to be set forth in an amended or
         supplemented prospectus which has not been so set forth, (D) subsequent
         to the respective dates as of which information is given in the Time of
         Sale Disclosure Package, the Company has not incurred any material
         liabilities or obligations, direct or contingent, or entered into any
         material transactions, not in the ordinary course of business, or
         declared or paid any dividends or made any distribution of any kind
         with respect to its capital stock, and except as disclosed in the Time
         of Sale Disclosure Package and in the Prospectus, there has not been
         any change in the capital stock (other than a change in the number of
         outstanding shares of Common Stock due to the issuance of shares upon
         the exercise of outstanding options or warrants), or any material
         change in the short-term or long-term debt, or any issuance of options,
         warrants, convertible securities or other rights to purchase the
         capital stock (other than grants of stock options under the Company's
         stock option plans existing on the date hereof or the Company's 2006
         Stock Plan), of the Company or any Material Adverse Change or any
         development involving a prospective Material Adverse Change (whether or
         not arising in the ordinary course of business), and (E) except as
         stated in the Time of Sale Disclosure Package and in the Prospectus,
         there is not pending, or, to the knowledge of the Company, threatened
         or contemplated, any action, suit or proceeding to which the Company is
         a party before or by any court or governmental agency, authority or
         body, or any arbitrator, which would reasonably be expected to result
         in any Material Adverse Change.

            (j) The Company shall have furnished to you and counsel for the
Underwriters such additional documents, certificates and evidence as you or they
may have reasonably requested.

            (k) At each Closing Date, counsel for the Underwriters shall have
been furnished with such information, certificates and documents as they may
reasonably require for the purpose of enabling them to pass upon the issuance
and sale of the Securities as contemplated herein and related proceedings, or to
evidence the accuracy of any of the


                                      -23-
<Page>


representations or warranties, or the fulfillment of any of the conditions,
herein contained, or otherwise in connection with the offering of the Securities
contemplated hereby.

            All such opinions, certificates, letters and other documents will be
in compliance with the provisions hereof only if they are reasonably
satisfactory in form and substance to you and counsel for the Underwriters. The
Company will furnish you with such conformed copies of such opinions,
certificates, letters and other documents as you shall reasonably request.

         6. INDEMNIFICATION AND CONTRIBUTION.

            (a) The Company agrees to indemnify and hold harmless each
Underwriter against any losses, claims, damages or liabilities, joint or
several, to which such Underwriter may become subject, under the Act or
otherwise (including in settlement of any litigation if such settlement is
effected with the written consent of the Company), 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, including the information deemed
to be a part of the Registration Statement at the time of effectiveness and at
any subsequent time pursuant to Rules 430A and 430C of the Rules and
Regulations, if applicable, any Preliminary Prospectus, the Time of Sale
Disclosure Package, the Prospectus, or any amendment or supplement thereto, any
Issuer Free Writing Prospectus or in any materials or information provided to
investors by, or with the approval of, the Company in connection with the
marketing of the offering of the Common Stock ("MARKETING MATERIALS"), including
any road show or investor presentations made to investors by the Company
(whether in person or electronically) 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 for any legal or other expenses reasonably
incurred by it in connection with investigating or defending against such loss,
claim, damage, liability or action; PROVIDED, HOWEVER, that the Company shall
not be liable in any such case to the extent that any such loss, claim, damage,
liability or action 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 Time of Sale Disclosure
Package, the Prospectus, or any such amendment or supplement, any Issuer Free
Writing Prospectus or in any Marketing Materials, in reliance upon and in
conformity with written information furnished to the Company by you, or by any
Underwriter through you, specifically for use in the preparation thereof.

            In addition to its other obligations under this Section 6(a), the
Company agrees that, as an interim measure during the pendency of any claim,
action, investigation, inquiry or other proceeding arising out of or based upon
any statement or omission, or any alleged statement or omission, described in
this Section 6(a), it will reimburse each Underwriter on a monthly basis for all
reasonable legal fees or other expenses incurred in connection with
investigating or defending any such claim, action, investigation, inquiry or
other proceeding, notwithstanding the absence of a judicial determination as to
the propriety and enforceability of the Company's obligation to reimburse the
Underwriters for such expenses and the possibility that such payments might
later be held to have been improper by a court of competent


                                      -24-
<Page>


jurisdiction. To the extent that any such interim reimbursement payment is so
held to have been improper, the Underwriter that received such payment shall
promptly return it to the party or parties that made such payment, together with
interest, compounded daily, determined on the basis of the prime rate (or other
commercial lending rate for borrowers of the highest credit standing) announced
from time to time by U.S. Bank (the "PRIME RATE"). Any such interim
reimbursement payments which are not made to an Underwriter within 30 days of a
request for reimbursement shall bear interest at the Prime Rate from the date of
such request. This indemnity agreement shall be in addition to any liabilities
which the Company may otherwise have.

            (b) Each Underwriter will indemnify and hold harmless the Company
against any losses, claims, damages or liabilities to which the Company may
become subject, under the Act or otherwise (including in settlement of any
litigation, if such settlement is effected with the written consent of such
Underwriter), 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, including the information deemed to be a part of the Registration
Statement at the time of effectiveness and at any subsequent time pursuant to
Rules 430A and 430C of the Rules and Regulations, if applicable, any Preliminary
Prospectus, the Time of Sale Disclosure Package, 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
Time of Sale Disclosure Package, the Prospectus, or any such amendment or
supplement, or any Issuer Free Writing Prospectus in reliance upon and in
conformity with written information furnished to the Company by you, or by such
Underwriter through you, specifically for use in the preparation thereof, and
will reimburse the Company for any legal or other expenses reasonably incurred
by the Company in connection with investigating or defending against any such
loss, claim, damage, liability or action.

            (c) Promptly after receipt by an indemnified party under subsection
(a) or (b) 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 the indemnifying party from any liability
that it may have to any indemnified party except to the extent such indemnifying
party has been materially prejudiced by such failure. 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 in, 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, and after notice from the
indemnifying party to such indemnified party of the indemnifying party's
election so to assume the defense thereof, the indemnifying party shall not be
liable to such indemnified party under such subsection for any legal or other
expenses subsequently incurred by such indemnified party in connection with the
defense


                                      -25-
<Page>


thereof other than reasonable costs of investigation; provided, however, that
if, in the sole judgment of the Representatives, it is advisable for the
Underwriters to be represented as a group by separate counsel, the
Representatives shall have the right to employ a single counsel to represent the
Representatives and all Underwriters who may be subject to liability arising
from any claim in respect of which indemnity may be sought by the Underwriters
under subsection (a) of this Section 6, in which event the reasonable fees and
expenses of such separate counsel shall be borne by the indemnifying party or
parties and reimbursed to the Underwriters as incurred (in accordance with the
provisions of the second paragraph in subsection (a) above). An indemnifying
party shall not be obligated under any settlement agreement relating to any
action under this Section 6 to which it has not agreed in writing. In addition,
no indemnifying party shall, without the prior written consent of the
indemnified party (which consent shall not be unreasonably withheld or delayed),
effect any settlement of any pending or threatened proceeding unless such
settlement includes an unconditional release of such indemnified party for all
liability on claims that are the subject matter of such proceeding.

            (d) If the indemnification provided for in this Section 6 is
unavailable or insufficient to hold harmless an indemnified party under
subsection (a) or (b) above, then each indemnifying party shall contribute to
the amount paid or payable by such indemnified party as a result of the losses,
claims, damages or liabilities referred to in subsection (a) or (b) above, (i)
in such proportion as is appropriate to reflect the relative benefits received
by the Company on the one hand and the Underwriters on the other from the
offering of the Securities or (ii) if the allocation provided by clause (i)
above is not permitted by applicable law, in such proportion as is appropriate
to reflect not only the relative benefits referred to in clause (i) above but
also the relative fault of the Company on the one hand and the Underwriters on
the other in connection with the statements or omissions that resulted in such
losses, claims, damages or liabilities, as well as any other relevant equitable
considerations. The relative benefits received by the Company on the one hand
and the Underwriters on the other shall be deemed to be in the same proportion
as the total net proceeds from the offering (before deducting expenses) received
by the Company 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 Underwriters and the parties'
relevant intent, knowledge, access to information and opportunity to correct or
prevent such untrue statement or omission. The Company and the Underwriters
agree that it would not be just and equitable if contributions pursuant to this
subsection (d) were to be determined by pro rata allocation (even if the
Underwriters were treated as one entity for such purpose) or by any other method
of allocation which does not take account of the equitable considerations
referred to in the first sentence of this subsection (d). The amount paid by an
indemnified party as a result of the losses, claims, damages or liabilities
referred to in the first sentence of this subsection (d) shall be deemed to
include any legal or other expenses reasonably incurred by such indemnified
party in connection with investigating or defending against any action or claim
which is the subject of this subsection (d). Notwithstanding the provisions of
this subsection (d), no Underwriter shall be required to contribute any amount
in excess of the


                                      -26-
<Page>


amount by which the total price at which the Securities underwritten by it and
distributed to the public were offered to the public exceeds the amount of any
damages that 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 (d) to contribute are several in proportion to their respective
underwriting obligations and not joint.

            (e) The obligations of the Company under this Section 6 shall be in
addition to any liability which the Company 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 the obligations of the
Underwriters under this Section 6 shall be in addition to any liability that the
respective Underwriters may otherwise have and shall extend, upon the same terms
and conditions, to each director of the Company (including any person who, with
his consent, is named in the Registration Statement as about to become a
director of the Company), to each officer of the Company who has signed the
Registration Statement and to each person, if any, who controls the Company
within the meaning of the Act.

            (f) The Underwriters severally confirm and the Company acknowledges
that the statements with respect to the public offering of the Securities by the
Underwriters set forth on the cover page of and elsewhere in, and the concession
and reallowance figures appearing under the caption "Underwriting" in the
Registration Statement, any Preliminary Prospectus, the Time of Sale Disclosure
Package and the Prospectus are correct and constitute the only information
concerning such Underwriters furnished in writing to the Company by or on behalf
of the Underwriters specifically for inclusion in the Registration Statement,
any Preliminary Prospectus, the Time of Sale Disclosure Package, the Prospectus
or any Issuer Free Writing Prospectus.

            (g) In connection with the offer and sale of the Directed Stock, the
Company agrees, promptly upon a request in writing, to indemnify and hold
harmless the Underwriters from and against any and all losses, liabilities,
claims, damages and expenses incurred by them as a result of the failure of the
Directed Stock Participants to affirmatively reconfirm the Directed Stock for
purchase as of the date of this Agreement or to pay for and accept delivery of
the Directed Stock by the end of the First Closing Date.

         7. REPRESENTATIONS AND AGREEMENTS TO SURVIVE DELIVERY. All
representations, warranties, and agreements of the Company herein or in
certificates delivered pursuant hereto, and the agreements of the several
Underwriters and the Company contained in Section 6 hereof, shall remain
operative and in full force and effect regardless of any investigation made by
or on behalf of any Underwriter or any controlling person thereof, or the
Company or any of its officers, directors, or controlling persons, and shall
survive delivery of, and payment for, the Securities to and by the Underwriters
hereunder.


                                      -27-
<Page>


         8. SUBSTITUTION OF UNDERWRITERS.

            (a) If any Underwriter or Underwriters shall fail to take up and pay
for the amount of Firm Shares agreed by such Underwriter or Underwriters to be
purchased hereunder, upon tender of such Firm Shares in accordance with the
terms hereof, and the amount of Firm Shares not purchased does not aggregate
more than 10% of the total amount of Firm Shares set forth in Schedule I hereto,
the remaining Underwriters shall be obligated to take up and pay for (in
proportion to their respective underwriting obligations hereunder as set forth
in Schedule I hereto except as may otherwise be determined by you) the Firm
Shares that the withdrawing or defaulting Underwriters agreed but failed to
purchase.

            (b) If any Underwriter or Underwriters shall fail to take up and pay
for the amount of Firm Shares agreed by such Underwriter or Underwriters to be
purchased hereunder, upon tender of such Firm Shares in accordance with the
terms hereof, and the amount of Firm Shares not purchased aggregates more than
10% of the total amount of Firm Shares set forth in Schedule I hereto, and
arrangements satisfactory to you for the purchase of such Firm Shares by other
persons are not made within 36 hours thereafter, this Agreement shall terminate.
In the event of any such termination the Company shall not be under any
liability to any Underwriter (except to the extent provided in Section
4(a)(viii) and Section 6 hereof) nor shall any Underwriter (other than an
Underwriter who shall have failed, otherwise than for some reason permitted
under this Agreement, to purchase the amount of Firm Shares agreed by such
Underwriter to be purchased hereunder) be under any liability to the Company
(except to the extent provided in Section 6 hereof).

            If Firm Shares to which a default relates are to be purchased by the
non-defaulting Underwriters or by any other party or parties, the
Representatives or the Company shall have the right to postpone the First
Closing Date for not more than seven business days in order that the necessary
changes in the Registration Statement, in the Time of Sale Disclosure Package,
in the Prospectus or in any other documents, as well as any other arrangements,
may be effected. As used herein, the term "Underwriter" includes any person
substituted for an Underwriter under this Section 8.

         9. EFFECTIVE DATE OF THIS AGREEMENT AND TERMINATION.

            (a) This Agreement shall become effective at [_____] a.m., Eastern
time, on the first full business day following the effective date of the
Registration Statement, or at such earlier time after the effective time of the
Registration Statement as you in your discretion shall first release the
Securities for sale to the public; PROVIDED, that if the Registration Statement
is effective at the time this Agreement is executed, this Agreement shall become
effective at such time as you in your discretion shall first release the
Securities for sale to the public. For the purpose of this Section, the
Securities shall be deemed to have been released for sale to the public upon
release by you of an electronic communication authorizing commencement of the
offering the Securities for sale by the Underwriters or other securities
dealers. By giving notice as hereinafter specified before the time this
Agreement becomes effective, you, as Representatives of the several
Underwriters, or the Company, may prevent this Agreement from


                                      -28-
<Page>


becoming effective without liability of any party to any other party, except
that the provisions of Section 4(a)(viii) and Section 6 hereof shall at all
times be effective.

            (b) You, as Representatives of the several Underwriters, shall have
the right to terminate this Agreement by giving notice as hereinafter specified
at any time at or prior to the First Closing Date, and the option referred to in
Section 3(b), if exercised, may be cancelled at any time prior to the Second
Closing Date, if (i) the Company shall have failed, refused or been unable, at
or prior to such Closing Date, to perform any agreement on its part to be
performed hereunder, (ii) any other condition of the Underwriters' obligations
hereunder is not fulfilled, (iii) trading on the Nasdaq Stock Market, New York
Stock Exchange or the American Stock Exchange shall have been wholly suspended,
(iv) minimum or maximum prices for trading shall have been fixed, or maximum
ranges for prices for securities shall have been required, on the Nasdaq Stock
Market, New York Stock Exchange or the American Stock Exchange, by such Exchange
or by order of the Commission or any other governmental authority having
jurisdiction, (v) a banking moratorium shall have been declared by federal or
state authorities, or (vi) there shall have occurred any outbreak or escalation
of hostilities or any change in financial markets or any calamity or crisis
that, in your judgment, is material and adverse and makes it impractical or
inadvisable to proceed with the completion of the sale of and payment for the
Securities. Any such termination shall be without liability of any party to any
other party except that the provisions of Section 4(a)(viii) and Section 6
hereof shall at all times be effective.

            (c) If you elect to prevent this Agreement from becoming effective
or to terminate this Agreement as provided in this Section, the Company shall be
notified promptly by you by telephone, confirmed by letter. If the Company
elects to prevent this Agreement from becoming effective, you shall be notified
by the Company by telephone, confirmed by letter.

         10. DEFAULT BY THE COMPANY. If the Company shall fail at the First
Closing Date to sell and deliver the number of Securities which it is obligated
to sell hereunder, then this Agreement shall terminate without any liability on
the part of any non-defaulting party.

             No action taken pursuant to this Section shall relieve the Company
so defaulting from liability, if any, in respect of such default.

         11. NOTICES. Except as otherwise provided herein, all communications
hereunder shall be in writing and, if to the Underwriters, shall be mailed or
delivered to the Representatives c/o Piper Jaffray & Co., 800 Nicollet Mall,
Minneapolis, Minnesota 55402, except that notices given to an Underwriter
pursuant to Section 6 hereof shall be sent to such Underwriter at the address
stated in the Underwriters' Questionnaire furnished by such Underwriter in
connection with this offering with a copy to Latham & Watkins LLP, 885 Third
Avenue, New York, New York 10022, Attention: Charles Ruck, Esq.; if to the
Company, shall be mailed or delivered to it at 21 Erie Street, Cambridge,
Massachusetts 02139, Attention: James J. Barber, with a copy to Goodwin Procter
LLP, Exchange Place, 53 State Street, Boston, Massachusetts 02109, Attention:
John M. Mutkoski, Esq.; or in each case to such


                                      -29-
<Page>


other address as the person to be notified may have requested in writing. Any
party to this Agreement may change such address for notices by sending to the
parties to this Agreement written notice of a new address for such purpose.

         12. PERSONS ENTITLED TO BENEFIT OF AGREEMENT. This Agreement shall
inure to the benefit of and be binding upon the parties hereto and their
respective successors and assigns and the controlling persons, officers and
directors referred to in Section 6. Nothing in this Agreement is intended or
shall be construed to give to any other person, firm or corporation any legal or
equitable remedy or claim under or in respect of this Agreement or any provision
herein contained. The term "successors and assigns" as herein used shall not
include any purchaser, as such purchaser, of any of the Securities from any of
the several Underwriters.

         13. ABSENCE OF FIDUCIARY RELATIONSHIP. The Company acknowledges and
agrees that: (a) the Representatives have been retained solely to act as an
underwriter in connection with the sale of the Securities and that no fiduciary,
advisory or agency relationship between the Company and the Representatives have
been created in respect of any of the transactions contemplated by this
Agreement, irrespective of whether the Representatives have advised or are
advising the Company on other matters; (b) the price and other terms of the
Securities set forth in this Agreement were established by the Company following
discussions and arms-length negotiations with the Representatives and the
Company is capable of evaluating and understanding and understands and accepts
the terms, risks and conditions of the transactions contemplated by this
Agreement; (c) it has been advised that the Representatives and their affiliates
are engaged in a broad range of transactions which may involve interests that
differ from those of the Company and that the Representatives have no obligation
to disclose such interest and transactions to the Company by virtue of any
fiduciary, advisory or agency relationship; (d) it has been advised that the
Representatives are acting, in respect of the transactions contemplated by this
Agreement, solely for the benefit of the Representatives and the other
Underwriters, and not on behalf of the Company; and (e) it waives to the fullest
extent permitted by law, any claims it may have against the Representatives for
breach of fiduciary duty or alleged breach of fiduciary duty in respect of any
of the transactions contemplated by this Agreement and agrees that the
Representatives shall have no liability (whether direct or indirect) to the
Company in respect of such a fiduciary duty claim on behalf of or in right of
the Company, including stockholders, employees or creditors of the Company.

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

         15. COUNTERPARTS. This Agreement may be executed in one or more
counterparts and, if executed in more than one counterpart, the executed
counterparts shall each be deemed to be an original and all such counterparts
shall together constitute one and the same instrument.

                            [Signature Page Follows]


                                      -30-
<Page>


         Please sign and return to the Company the enclosed duplicates of
this letter whereupon this letter will become a binding agreement between the
Company and the several Underwriters in accordance with its terms.

                                      Very truly yours,

                                      METABOLIX, INC.

                                      By
                                         -------------------------------------
                                         James J. Barber,
                                         President and Chief Executive Officer


Confirmed as of the date first
above mentioned, on behalf of
themselves and the other several
Underwriters named in Schedule I
hereto.


PIPER JAFFRAY & CO.


By:
    ------------------------------------

Name:
      ----------------------------------

Title:
       ---------------------------------



JEFFERIES & COMPANY, INC.


By:
    ------------------------------------

Name:
      ----------------------------------

Title:
       ---------------------------------



                     [Signatures Continued on the Next Page]



<Page>


THOMAS WEISEL PARTNERS LLC


By:
    ------------------------------------

Name:
      ----------------------------------

Title:
       ---------------------------------



ARDOUR CAPITAL INVESTMENTS, LLC


By:
    ------------------------------------

Name:
      ----------------------------------

Title:
       ---------------------------------


<Page>


                                   SCHEDULE I



UNDERWRITER                                         NUMBER OF FIRM SHARES (1)
- -----------                                         -------------------------
Piper Jaffray & Co.
Jefferies & Company, Inc.
Thomas Weisel Partners LLC
Ardour Capital Investments, LLC
                                                         ---------------


Total
      ------------------------------



- -----------------

(1)      The Underwriters may purchase up to an additional [_____] Option
         Shares, to the extent the option described in Section 3(b) of the
         Agreement is exercised, in the proportions and in the manner described
         in the Agreement.


<Page>


                                   SCHEDULE II

                    ISSUER GENERAL FREE WRITING PROSPECTUSES



<Page>


                                    EXHIBIT A

                        OPINION OF GOODWIN | PROCTER LLP



<Page>


                                    EXHIBIT B-1

                        OPINION OF PABST PATENT GROUP LLP


<Page>


                                    EXHIBIT B-2

                           OPINION OF FISH & RICHARDSON