Exhibit 1.1

                                                                  EXECUTION COPY

                                4,555,270 SHARES

                                 ILLUMINA, INC.

                             SHARES OF COMMON STOCK
                                ($.01 PAR VALUE)

                            PLACEMENT AGENT AGREEMENT

                                                                    May 10, 2004

SG COWEN & CO., LLC
1221 Avenue of the Americas
New York, New York 10020

Dear Sirs:

      Illumina, Inc., a Delaware corporation (the "COMPANY"), proposes to sell
to the Purchasers, pursuant to the terms of this Placement Agent Agreement (this
"AGREEMENT") and the Subscription Agreements in the form of Exhibit A attached
hereto (the "SUBSCRIPTION AGREEMENTS") entered into with the Purchasers
identified therein (each a "PURCHASER" and, collectively, the "PURCHASERS"), an
aggregate of 4,555,270 shares of Common Stock, $.01 par value (the "COMMON
STOCK"), of the Company. The aggregate of 4,555,270 shares so proposed to be
sold is hereinafter referred to as the "STOCK." The Company hereby confirms its
agreement with SG Cowen & Co., LLC ("SG COWEN") as follows (certain terms used
herein are defined in Section 13 hereof):

1.    AGREEMENT TO ACT AS PLACEMENT AGENT; PLACEMENT OF SECURITIES. On the basis
of the representations, warranties and agreements of the Company herein
contained, and subject to all the terms and conditions of this Agreement:

      (a)   The Company hereby authorizes SG Cowen to act as its exclusive agent
      (in such capacity, the "PLACEMENT AGENT") to solicit offers for the
      purchase of all or part of the Stock from the Company in connection with
      the proposed offering of the Stock (the "OFFERING"). Until the earlier of
      the Closing Date or the termination of this Agreement, the Company shall
      not, without the prior consent of the Placement Agent, solicit or accept
      offers to purchase Stock otherwise than through the Placement Agent.

      (b)   The Placement Agent agrees, as agent of the Company, to use its
      commercially reasonable efforts to solicit offers to purchase the Stock
      from the Company on the terms and subject to the conditions set forth in
      the Base Prospectus (as defined below) and the Prospectus Supplement (as
      defined below). The Placement Agent shall make commercially reasonable
      efforts to assist the Company in obtaining performance by each Purchaser
      whose offer



      to purchase Stock has been solicited by the Placement Agent and accepted
      by the Company, but the Placement Agent shall not, except as otherwise
      provided in this Agreement, be obligated to disclose the identity of any
      potential purchaser or have any liability to the Company in the event any
      such purchase is not consummated for any reason. Under no circumstances
      will the Placement Agent be obligated to purchase any Stock for its own
      account and, in soliciting purchases of Stock, the Placement Agent shall
      act solely as the Company's agent and not as principal. Notwithstanding
      the foregoing and except as otherwise provided in Section 1(c), it is
      understood and agreed that the Placement Agent (or its affiliates) may,
      solely at its discretion and without any obligation to do so, purchase
      Stock as principal; provided, however, that any such purchases by the
      Placement Agent (or its affiliates) shall be fully disclosed to the
      Company (including the identity of such purchaser) and approved by the
      Company in accordance with Section 1(c).

      (c)   Subject to the provisions of this Section 1, offers for the purchase
      of Stock may be solicited by the Placement Agent as agent for the Company
      at such times and in such amounts as the Placement Agent deems advisable.
      The Placement Agent shall communicate to the Company, orally or in
      writing, each reasonable offer to purchase Stock received by it as agent
      of the Company. The Company shall have the sole right to accept offers to
      purchase the Stock and may reject any such offer, in whole or in part.

      (d)   The purchases of the Stock by the Purchasers shall be evidenced by
      the execution of the Subscription Agreements by each of the parties
      thereto.

      (e)   As compensation for services rendered, on the Closing Date (as
      defined below) the Company shall pay to the Placement Agent by wire
      transfer of immediately available funds to an account or accounts
      designated by the Placement Agent, an amount equal to six percent (6.0%)
      of the gross proceeds received by the Company from the sale of the Stock
      on such Closing Date.

      (f)   No Stock which the Company has agreed to sell pursuant to this
      Agreement shall be deemed to have been purchased and paid for, or sold by
      the Company, until such Stock shall have been delivered to the Purchaser
      thereof against payment by such Purchaser. If the Company shall default in
      its obligations to deliver Stock to a Purchaser whose offer it has
      accepted, the Company shall indemnify and hold the Placement Agent
      harmless against any loss, claim or damage arising from or as a result of
      such default by the Company.

2.    REPRESENTATIONS AND WARRANTIES OF THE COMPANY AND ITS SUBSIDIARIES. The
Company and its subsidiaries represent and warrant to, and agree with, the
Placement Agent and the Purchasers that:

      (a)   The Company meets the requirements for use of Form S-3 under the
      Securities Act of 1933, as amended (the "SECURITIES ACT"), and has filed
      with the Securities and Exchange Commission (the "COMMISSION") a
      registration statement on such Form (Registration File No. 333-111496),
      which became

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      effective as of April 14, 2004, for the registration under the Securities
      Act of the Stock. Such registration statement meets the requirements set
      forth in Rule 415(a)(1)(x) under the Securities Act and complies in all
      material respects with said Rule. The Company will file with the
      Commission pursuant to Rule 424(b) under the Securities Act, and the rules
      and regulations (the "RULES AND REGULATIONS") of the Commission
      promulgated thereunder, a supplement to the form of prospectus included in
      such registration statement relating to the placement of the Stock and the
      plan of distribution thereof and has advised the Placement Agent of all
      further information (financial and other) with respect to the Company
      required to be set forth therein. Such registration statement, including
      the exhibits thereto, as amended at the date of this Agreement, is
      hereinafter called the "REGISTRATION STATEMENT"; such prospectus in the
      form in which it appears in the Registration Statement is hereinafter
      called the "BASE PROSPECTUS"; and the supplemented form of prospectus, in
      the form in which it will be filed with the Commission pursuant to Rule
      424(b) (including the Base Prospectus as so supplemented) is hereinafter
      called a "PROSPECTUS SUPPLEMENT." Any reference herein to the Registration
      Statement, the Base Prospectus or the Prospectus Supplement shall be
      deemed to refer to and include the documents incorporated by reference
      therein (the "INCORPORATED DOCUMENTS") pursuant to Item 12 of Form S-3
      which were filed under the Securities Exchange Act of 1934, as amended
      (the "EXCHANGE ACT"), on or before the date of this Agreement, or the
      issue date of the Base Prospectus or the Prospectus Supplement, as the
      case may be; and any reference herein to the terms "amend," "amendment" or
      "supplement" with respect to the Registration Statement, the Base
      Prospectus or the Prospectus Supplement shall be deemed to refer to and
      include the filing of any document under the Exchange Act after the date
      of this Agreement, or the issue date of the Base Prospectus or the
      Prospectus Supplement, as the case may be, deemed to be incorporated
      therein by reference. All references in this Agreement to financial
      statements and schedules and other information which is "contained,"
      "included," "described," "set forth" or "stated" in the Registration
      Statement, the Base Prospectus or the Prospectus Supplement (and all other
      references of like import) shall be deemed to mean and include all such
      financial statements and schedules and other information which is or is
      deemed to be incorporated by reference in the Registration Statement, the
      Base Prospectus or the Prospectus Supplement, as the case may be. No stop
      order suspending the effectiveness of the Registration Statement or the
      use of the Base Prospectus or the Prospectus Supplement has been issued,
      and no proceeding for any such purpose is pending or has been initiated
      or, to the Company's knowledge, is threatened by the Commission.

      (b)   The Registration Statement (and any further documents to be filed
      with the Commission) contains all exhibits and schedules as required by
      the Securities Act. Each of the Registration Statement and any
      post-effective amendment thereto, at the time it became effective,
      complied in all material respects with the Securities Act and the Exchange
      Act and the applicable Rules and Regulations and did not and, as amended
      or supplemented, if applicable, will not, contain any untrue statement of
      a material fact or omit to state a material fact required to be stated
      therein or necessary to make the statements therein not misleading. The
      Base Prospectus and the Prospectus

                                       3


      Supplement, each as of its respective date, comply in all material
      respects with the Securities Act and the Exchange Act and the applicable
      Rules and Regulations. Each of the Base Prospectus and the Prospectus
      Supplement, as amended or supplemented, did not and will not contain as of
      the date thereof any untrue statement of a material fact or omit to state
      a material fact necessary in order to make the statements therein, in
      light of the circumstances under which they were made, not misleading. The
      Incorporated Documents, when they were filed with the Commission,
      conformed in all material respects to the requirements of the Exchange Act
      and the applicable Rules and Regulations, and none of such documents, when
      they were filed with the Commission, contained any untrue statement of a
      material fact or omitted to state a material fact necessary to make the
      statements therein not misleading; and any further documents so filed and
      incorporated by reference in the Base Prospectus or Prospectus Supplement,
      when such documents are filed with the Commission, will conform in all
      material respects to the requirements of the Exchange Act and the
      applicable Rules and Regulations, as applicable, and will not contain any
      untrue statement of a material fact or omit to state a material fact
      necessary to make the statements therein not misleading. Notwithstanding
      the foregoing, the Company makes no representations or warranties as to
      information, if any, contained in or omitted from the Prospectus
      Supplement or any amendment thereof or supplement thereto in reliance upon
      and in conformity with information furnished in writing to the Company by
      or on behalf of the Placement Agent specifically for use in the
      Registration Statement or the Prospectus Supplement, which information the
      parties hereto agree is limited to the Placement Agent's Information as
      defined in Section 15. No post-effective amendment to the Registration
      Statement reflecting any facts or events arising after the date thereof
      which represent, individually or in the aggregate, a fundamental change in
      the information set forth therein is required to be filed with the
      Commission. There are no documents required to be filed with the
      Commission in connection with the transaction contemplated hereby that (x)
      have not been filed as required pursuant to the Securities Act or (y) will
      not be filed within the requisite time period. There are no contracts or
      other documents required to be described in the Base Prospectus or
      Prospectus Supplement, or to be filed as exhibits or schedules to the
      Registration Statement, which have not been described or filed as
      required.

      (c)   The Company has delivered, or will as promptly as practicable
      deliver, to the Placement Agent complete conformed copies of the
      Registration Statement and of each consent and certificate of experts
      filed as a part thereof, and conformed copies of the Registration
      Statement (without exhibits) and the Base Prospectus and the Prospectus
      Supplement, as amended or supplemented, in such quantities and at such
      places as the Placement Agent reasonably requests. Neither the Company nor
      any of its directors and officers has distributed and none of them will
      distribute, prior to the Closing Date, any offering material in connection
      with the offering and sale of the Stock other than the Base Prospectus,
      the Prospectus Supplement, the Registration Statement, copies of the
      documents incorporated by reference therein and any other materials
      permitted by the Securities Act.

                                       4


      (d)   The Company and each of its subsidiaries have been duly incorporated
      and are validly existing as corporations or other legal entities in good
      standing (or the equivalent thereof, if any) under the laws of their
      respective jurisdictions of incorporation, are duly qualified to do
      business and are in good standing (or the equivalent thereof, if any) as
      foreign corporations in each jurisdiction in which their respective
      ownership or lease of property or the conduct of their respective
      businesses requires such qualification, and have all corporate power and
      authority necessary to own or hold their respective properties and to
      conduct the businesses in which they are engaged, except where the failure
      to be so qualified and in good standing or have such power or authority
      would not have, singularly or in the aggregate, a material adverse effect
      on the condition (financial or otherwise), results of operations,
      business, properties or prospects of the Company and its subsidiaries
      taken as a whole (a "MATERIAL ADVERSE EFFECT").

      (e)   The Stock to be issued and sold by the Company hereunder and under
      the Subscription Agreements has been duly and validly authorized and, when
      issued and delivered against payment therefor as provided herein, will be
      duly and validly issued, fully paid and nonassessable and free of any
      preemptive or similar rights. The Stock conforms to the description
      thereof contained in the Base Prospectus and the Prospectus Supplement.

      (f)   As of the date of this Agreement and as of the Closing Date, the
      Company has an authorized capitalization as set forth in the Base
      Prospectus and the Prospectus Supplement, all of the issued and
      outstanding shares of capital stock of the Company have been duly and
      validly authorized and issued, are fully paid and non-assessable, have
      been issued in compliance with federal and state securities laws, and
      conform to the description thereof contained in the Base Prospectus and
      the Prospectus Supplement. None of the outstanding shares of Common Stock
      was issued in violation of any preemptive rights, rights of first refusal
      or other similar rights to subscribe for or purchase securities of the
      Company. There are no authorized or outstanding options, warrants,
      preemptive rights, rights of first refusal or other rights to purchase, or
      equity or debt securities convertible into or exchangeable or exercisable
      for, any capital stock of the Company or any of its subsidiaries that have
      been granted by the Company other than as set forth in the Base Prospectus
      and the Prospectus Supplement.

      (g)   All the outstanding shares of capital stock of each subsidiary of
      the Company have been duly authorized and validly issued, are fully paid
      and nonassessable and, except to the extent set forth in the Base
      Prospectus and the Prospectus Supplement, are owned by the Company
      directly or indirectly through one or more wholly-owned subsidiaries, free
      and clear of any claim, lien, encumbrance, security interest, defect or
      restriction upon voting or transfer or any other claim of any kind
      ("LIENS").

      (h)   The Company has the full right, power and authority to enter into
      this Agreement and each of the Subscription Agreements and to perform and
      to discharge its obligations hereunder and thereunder; and each of this
      Agreement and each of the Subscription Agreements has been duly

                                       5


      authorized, executed and delivered by the Company, and constitutes a valid
      and binding obligation of the Company enforceable against the Company in
      accordance with its terms.

      (i)   The execution, delivery and performance of this Agreement and the
      Subscription Agreements by the Company and the consummation of the
      transactions contemplated hereby and thereby will not conflict with or
      result in a breach or violation of any of the terms or provisions of, or
      constitute a default under, any indenture, mortgage, deed of trust, loan
      agreement or other agreement or instrument to which the Company or any of
      its subsidiaries is a party or by which the Company or any of its
      subsidiaries is bound or to which any of the property or assets of the
      Company or any of its subsidiaries is subject, nor will such actions
      result in any violation of the provisions of the charter or by-laws of the
      Company or any of its subsidiaries or any statute, law, rule or regulation
      or any judgment, order or decree of any court or governmental agency or
      body having jurisdiction over the Company or any of its subsidiaries or
      any of their properties or assets.

      (j)   There is no franchise, contract, lease, instrument or other document
      of a character required by the Securities Act or the Rules and Regulations
      to be described in the Base Prospectus and the Prospectus Supplement, or
      to be filed as an exhibit to the Registration Statement, which is not
      described or filed as required; and all statements summarizing any such
      franchises, contracts, leases, instruments or other documents or legal
      matters contained in the Registration Statement are accurate and complete
      in all material respects. Other than as described in the Base Prospectus
      and the Prospectus Supplement, no such franchise, contract, lease,
      instrument or other document has been suspended or terminated for
      convenience or default by the Company or any of the other parties thereto,
      the Company has not sent or received any communication regarding intent
      not to renew any such franchise, contract, lease, instrument or other
      document, and the Company has not received notice or any other knowledge
      of any such pending or threatened suspension, termination or non-renewal,
      except for such pending or threatened suspensions, terminations or
      non-renewals that would not reasonably be expected to, singularly or in
      the aggregate, have a Material Adverse Effect.

      (k)   All existing minute books of the Company and each of its
      subsidiaries, including all existing records of all meetings and actions
      of the board of directors (including, Audit, Compensation,
      Nomination/Corporate Governance and other board committees) and
      stockholders of the Company through the date of the latest meeting and
      action (collectively, the "CORPORATE RECORDS") have been made available to
      the Placement Agent and counsel for the Placement Agent. All such
      Corporate Records are complete and accurately reflect, in all material
      respects, all transactions referred to in such Corporate Records. There
      are no material transactions, agreements or other actions of the Company
      that are not properly approved and/or recorded in the Corporate Records.

      (l)   No consent, approval, authorization, filing with or order of or
      registration with, any court or governmental agency or body is required in
      connection with the transactions contemplated herein and in the
      Subscription

                                       6


      Agreements, except such as have been obtained or made under the Securities
      Act or the Exchange Act and such as may be required under the securities,
      or blue sky, laws of any jurisdiction in connection with the offer and
      sale of the Stock by the Company in the manner contemplated herein and in
      the Base Prospectus and the Prospectus Supplement.

      (m)   Except as described in the Base Prospectus and the Prospectus
      Supplement, (i) no person has the right, contractual or otherwise, to
      cause the Company to issue or sell to it any shares of Common Stock or
      shares of any other capital stock or other equity interests of the
      Company, (ii) no person has any preemptive rights, resale rights, rights
      of first refusal or other rights to purchase any shares of Common Stock or
      shares of any other capital stock or other securities of the Company, and
      (iii) except as provided herein, no person has the right to act as an
      underwriter, placement agent or financial advisor to the Company in
      connection with and as a result of the offer and sale of the Shares, in
      the case of each of the foregoing clauses (i), (ii) and (iii), whether as
      a result of the filing or effectiveness of the Registration Statement or
      the sale of the Shares as contemplated thereby or otherwise; no person has
      the right, contractual or otherwise, to cause the Company to register
      under the Securities Act any shares of Common Stock or shares of any other
      capital stock or other securities of the Company, or to include any such
      shares or interests in the Registration Statement or the offering
      contemplated thereby, whether as a result of the filing or effectiveness
      of the Registration Statement or the sale of the Shares as contemplated
      thereby or otherwise, except for persons and entities who have expressly
      waived such right or who have been given timely and proper notice and have
      failed to exercise such right within the time or times required under the
      terms and conditions of such right, and the Company is not currently
      required to file any registration statement for the registration of any
      securities of any person or register any such securities pursuant to any
      other registration statement filed by the Company under the Securities Act
      for a period of at least 90 days after the date hereof.

      (n)   The financial statements, together with the related notes and
      schedules, of the Company included in the Base Prospectus, the Prospectus
      Supplement or the Registration Statement, or incorporated by reference
      therein, as the case may be, present fairly the financial condition,
      results of operations and cash flows of the Company and its consolidated
      subsidiaries and other consolidated entities as of the dates and for the
      periods indicated, comply in all material respects with the Securities Act
      and the Rules and Regulations thereunder, and have been prepared in
      conformity with generally accepted accounting principles applied on a
      consistent basis throughout the periods involved.

      (o)   Except as set forth in the Base Prospectus and the Prospectus
      Supplement, there is no legal or governmental proceeding pending to which
      the Company or any of its subsidiaries is a party or of which any property
      or assets of the Company or any of its subsidiaries is the subject which,
      singularly or in the aggregate, if determined adversely to the Company or
      any of its subsidiaries, would reasonably be expected to have a Material
      Adverse Effect or would prevent or adversely affect the ability of the
      Company to perform its obligations under this Agreement; and to the
      Company's

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      knowledge, no such proceedings are threatened by governmental authorities
      or threatened by others.

      (p)   The Company and each of its subsidiaries have good and marketable
      title to all property (real and personal) described in the Registration
      Statement, the Base Prospectus and the Prospectus Supplement as being
      owned by the Company or its subsidiaries, free and clear of all Liens,
      except for those Liens that do not materially interfere with the use made
      or proposed to be made of such property by the Company or its subsidiaries
      or that would not have a Material Adverse Effect; all the property
      described in the Registration Statement, the Base Prospectus and the
      Prospectus Supplement as being held under lease by the Company or a
      subsidiary is held thereby under valid, subsisting and enforceable leases
      except where the failure to be valid, subsisting or enforceable would not
      have a Material Adverse Effect.

      (q)   Neither the Company nor any of its subsidiaries is (i) in violation
      of any provision of its charter or bylaws, (ii) in default in any respect,
      and no event has occurred which, with notice or lapse of time or both,
      would constitute such a default, in the due performance or observance of
      any term, covenant, or condition of any indenture, contract, lease,
      mortgage, deed of trust, note agreement, loan agreement or other
      agreement, obligation, condition, covenant or instrument to which it is a
      party or by which it is bound or to which any of its property or assets is
      subject, or (iii) in violation in any respect of any statute, law, rule,
      regulation, ordinance, judgment, order or decree of any court, regulatory
      body, administrative agency, governmental body, arbitrator or other
      authority having jurisdiction over the Company, its subsidiaries or any of
      its properties, as applicable (including, without limitation, those
      administered by the Food and Drug Administration of the U.S. Department of
      Health and Human Services (the "FDA") or by any foreign, federal, state or
      local governmental or regulatory authority performing functions similar to
      those performed by the FDA), except, with respect to clauses (ii) and
      (iii), any violations or defaults which, singularly or in the aggregate,
      would not have a Material Adverse Effect.

      (r)   The contracts described in the Company's regular reports on Forms
      10-Q, 10-K, and 8-K as filed by the Company with the Commission or
      incorporated by reference therein that are material to the Company are in
      full force and effect on the date hereof, and neither the Company nor, to
      the Company's knowledge, any other party to such contracts is in breach of
      or default under any of such contracts which would have a Material Adverse
      Effect.

      (s)   No labor problem or dispute with the employees of the Company exists
      or, to the Company's knowledge, is threatened or imminent, which would
      reasonably be expected to have a Material Adverse Effect. The Company is
      not aware that any key employee or significant group of employees of the
      Company or any subsidiary plans to terminate employment with the Company
      or any such subsidiary.

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      (t)   Each of the Company and its subsidiaries has fulfilled its
      obligations, if any, under the minimum funding standards of Section 302 of
      the United States Employee Retirement Income Security Act of 1974
      ("ERISA") and the regulations and published interpretations thereunder
      with respect to each "PLAN" (as defined in Section 3(3) of ERISA and such
      regulations and published interpretations) in which employees of the
      Company and its subsidiaries are eligible to participate and each such
      plan is in compliance in all material respects with the presently
      applicable provisions of ERISA and such regulations and published
      interpretations. No "PROHIBITED TRANSACTION" (as defined in Section 406 of
      ERISA, or Section 4975 of the Internal Revenue Code of 1986, as amended
      from time to time (the "CODE")) has occurred with respect to any employee
      benefit plan which could have a Material Adverse Effect. The Company and
      each of its subsidiaries has not incurred any unpaid liability to the
      Pension Benefit Guaranty Corporation (other than for the payment of
      premiums in the ordinary course) or to any such plan under Title IV of
      ERISA. Each "PENSION PLAN" (as defined in ERISA) for which the Company
      would have any liability that is intended to be qualified under Section
      401(a) of the Code is so qualified in all material respects and nothing
      has occurred, whether by action or by failure to act, which could cause
      the loss of such qualification.

      (u)   The Company and each of its subsidiaries carry, or are covered by,
      insurance in such amounts and covering such risks as is adequate for the
      conduct of their respective businesses and the value of their respective
      properties and as is customary for companies engaged in similar businesses
      in similar industries; all such insurance is fully in force on the date
      hereof and will be fully in force on the Closing Date.

      (v)   The Company and each of its subsidiaries has made all filings,
      applications and submissions required by, and possesses all approvals,
      licenses, certificates, certifications, clearances, consents, exemptions,
      marks, notifications, orders, permits and other authorizations issued by,
      the appropriate federal, state or foreign regulatory authorities
      (including, without limitation, the FDA, and any other foreign, federal,
      state or local government or regulatory authorities performing functions
      similar to those performed by the FDA) necessary to conduct its businesses
      (collectively, "PERMITS"), and is in compliance with the terms and
      conditions of all such Permits, except for such Permits which if not
      obtained or complied with would not have a Material Adverse Effect; all of
      such Permits held by the Company and each of its subsidiaries are valid
      and in full force and effect except as would not have a Material Adverse
      Effect; there is no pending or threatened action, suit, claim or
      proceeding which may cause any such Permit to be limited, revoked,
      cancelled, suspended, modified or not renewed and the Company and each of
      its subsidiaries has not received any notice of proceedings relating to
      the limitation, revocation, cancellation, suspension, modification or
      non-renewal of any such Permit which, singly or in the aggregate, if the
      subject of an unfavorable decision, ruling or finding, would have a
      Material Adverse Effect, whether or not arising from transactions in the
      ordinary course of business, except as set forth in or contemplated by the
      Base Prospectus or the Prospectus Supplement.

                                       9


      (w)   Ernst & Young LLP, who have certified certain financial statements
      of the Company and delivered their report with respect to the audited
      consolidated financial statements and schedules included in the Base
      Prospectus, the Prospectus Supplement or the Registration Statement, or
      incorporated by reference therein, as the case may be, are independent
      public accountants with respect to the Company within the meaning of the
      Securities Act and the Rules and Regulations.

      (x)   The Company and each of its subsidiaries has filed all foreign,
      federal, state and local tax returns that are required to be filed or has
      requested extensions thereof (except in any case in which the failure so
      to file would not have a Material Adverse Effect, except as set forth in
      the Base Prospectus and the Prospectus Supplement) and has paid all taxes
      required to be paid by it and any other assessment, fine or penalty levied
      against it, to the extent that any of the foregoing is due and payable,
      except for any such assessment, fine or penalty that is currently being
      contested in good faith or as would not have a Material Adverse Effect,
      except as set forth in the Base Prospectus and the Prospectus Supplement.

      (y)   The principal executive officer and principal financial officer of
      the Company have made all certifications required by the Sarbanes-Oxley
      Act of 2002 and the rules and regulations promulgated in connection
      therewith (the "SARBANES-OXLEY ACT"), and the statements contained in any
      such certification are complete and correct. The Company maintains
      "disclosure controls and procedures" (as defined in Rule 13a-15(e) under
      the Exchange Act), and such controls and procedures are designed (i) 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 periods specified in
      the Commission's rules and forms and (ii) 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
      principal financial officer, as appropriate to allow timely decisions
      regarding required disclosure. There has been no fraud, whether or not
      material, that involves management or other employees who have a
      significant role in the Company's internal controls. The Company is
      otherwise in compliance in all respects with all applicable effective
      provisions of the Sarbanes-Oxley Act and the rules and regulations
      promulgated by the Commission (and intends to comply with all applicable
      provisions that are not yet effective upon effectiveness).

      (z)   The Company and each of its subsidiaries maintains a system of
      internal accounting controls sufficient to provide reasonable assurance
      that (i) transactions are executed in accordance with management's general
      or specific authorizations; (ii) transactions are recorded as necessary to
      permit preparation of financial statements in conformity with generally
      accepted accounting principles and to maintain accountability of 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

                                       10


      the existing assets at reasonable intervals and appropriate action is
      taken with respect to any differences.

      (aa)  The Company and each of its subsidiaries (i) is in compliance in all
      material respects with any and all applicable foreign, federal, state and
      local laws and regulations relating to the protection of human health and
      safety, the environment or hazardous or toxic substances or wastes,
      pollutants or contaminants ("ENVIRONMENTAL LAWS"), (ii) 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 (iii)
      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 where such
      non-compliance with Environmental Laws, failure to receive required
      permits, licenses or other approvals, or liability would not, individually
      or in the aggregate, have a Material Adverse Effect, whether or not
      arising from transactions in the ordinary course of business, except as
      set forth in or contemplated by the Base Prospectus and the Prospectus
      Supplement (exclusive of any supplement thereto). The Company has not been
      named as a "POTENTIALLY RESPONSIBLE PARTY" under the Comprehensive
      Environmental Response, Compensation, and Liability Act of 1980, as
      amended.

      (bb)  In the ordinary course of its business, the Company periodically
      reviews the effect of Environmental Laws on the business, operations and
      properties of the Company and each of its subsidiaries, in the course of
      which it identifies and evaluates associated costs and liabilities
      (including, without limitation, any capital or operating expenditures
      required for clean-up, closure of properties or compliance with
      Environmental Laws, or any permit, license or approval, any related
      constraints on operating activities and any potential liabilities to third
      parties). On the basis of such review, the Company has reasonably
      concluded that such associated costs and liabilities would not, singly or
      in the aggregate, have a Material Adverse Effect, whether or not arising
      from transactions in the ordinary course of business, except as set forth
      in or contemplated by the Base Prospectus and the Prospectus Supplement.

      (cc)  Except as set forth in the Base Prospectus and the Prospectus
      Supplement, the Company and its subsidiaries own, possess, license or have
      other rights to use all foreign and domestic patents, patent applications,
      trade and service marks, trade and service mark registrations, trade
      names, copyrights, licenses, inventions, trade secrets, technology,
      Internet domain names, know-how and other intellectual property
      (collectively, the "INTELLECTUAL PROPERTY") necessary for the conduct of
      the Company's business as now conducted or as proposed in the Base
      Prospectus and the Prospectus Supplement to be conducted. Except as set
      forth in the Base Prospectus and the Prospectus Supplement (a) there are
      no rights of third parties to any such Intellectual Property; (b) to the
      Company's knowledge, there is no infringement by third parties of any such
      Intellectual Property; (c) there is no pending or, to the Company's
      knowledge, threatened action, suit, proceeding or claim by others
      challenging the Company's and its subsidiaries' rights in or to any such
      Intellectual Property, and the Company is unaware of

                                       11


      any facts which would form a reasonable basis for any such claim; (d)
      there is no pending or, to the best of the Company's knowledge, threatened
      action, suit, proceeding or claim by others challenging the validity or
      scope of any such Intellectual Property; (e) there is no pending or, to
      the Company's knowledge, threatened action, suit, proceeding or claim by
      others that the Company and its subsidiaries infringe or otherwise violate
      any patent, trademark, copyright, trade secret or other proprietary rights
      of others, and the Company is unaware of any other fact which would form a
      reasonable basis for any such claim; and (f) to the Company's knowledge,
      there is no third-party U.S. patent or published U.S. patent application
      which contains claims for which an Interference Proceeding could be
      commenced against any patent or patent application described in the Base
      Prospectus and the Prospectus Supplement as being owned by or licensed to
      the Company, except for Interference Proceedings based on claims under any
      such patents or published patent applications as would not have a Material
      Adverse Effect.

      (dd)  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
      by applicable securities laws to be described in the Base Prospectus and
      the Prospectus Supplement and which is not so described.

      (ee)  Neither the Company nor, to the Company's knowledge, any other
      person associated with or acting on behalf of the Company including,
      without limitation, any director, officer, agent or employee of the
      Company or any of its subsidiaries, has, directly or indirectly, while
      acting on behalf of the Company or any of its subsidiaries (i) used any
      corporate funds for unlawful contributions, gifts, entertainment or other
      unlawful expenses, or received or retained any funds, relating to
      political activity; (ii) made any unlawful payment from corporate funds
      to, or received or retained any unlawful funds from, foreign or domestic
      government officials or employees or to or from foreign or domestic
      political parties or campaigns; or (iii) violated any provision of the
      Foreign Corrupt Practices Act of 1977, as amended.

      (ff)  Neither the Company nor any of its subsidiaries is or, after giving
      effect to the offering and sale of the Stock and the application of the
      proceeds thereof as described in the Base Prospectus and the Prospectus
      Supplement, will become an "INVESTMENT COMPANY" as defined in the
      Investment Company Act of 1940, as amended.

      (gg)  No forward-looking statement (within the meaning of Section 27A of
      the Securities Act and Section 21E of the Exchange Act) contained in the
      Base Prospectus and the Prospectus Supplement has been made or reaffirmed
      without a reasonable basis or has been disclosed other than in good faith.

      (hh)  Other than as contemplated by this Agreement, neither the Company
      nor any of its subsidiaries is a party to any contract, agreement or
      understanding with any person that would give rise to a valid claim
      against the Company or the Placement Agent for a brokerage commission,
      finder's fee or like payment in connection with the offering and sale of
      the Stock.

                                       12


      (ii)  Neither the Company nor any of its subsidiaries has sustained, since
      the date of the latest audited financial statements included in the Base
      Prospectus, the Prospectus Supplement or the Registration Statement, or
      incorporated by reference therein, as the case may be, any material loss
      or interference with its business from fire, explosion, flood, terrorist
      act or other calamity, whether or not covered by insurance, or from any
      labor dispute or court or governmental action, order or decree, otherwise
      than as set forth in the Base Prospectus and the Prospectus Supplement.

      (jj)  Except as set forth in or as otherwise contemplated by the
      Registration Statement, the Base Prospectus or the Prospectus Supplement,
      subsequent to the respective dates as of which information is given in the
      Registration Statement, the Base Prospectus and the Prospectus Supplement,
      there has not been (i) any material adverse change, or any development
      that would reasonably be expected to result in a material adverse change,
      in the business, properties, management, financial condition or results of
      operations of the Company taken as a whole, (ii) any transaction which is
      material to the Company taken as a whole, (iii) any obligation, direct or
      contingent (including any off-balance sheet obligations), incurred by the
      Company outside the ordinary course of business, which is material to the
      Company taken as a whole, (iv) any change in the capital stock (other than
      the issuance of shares of Common Stock upon exercise of stock options and
      warrants disclosed as outstanding in the Registration Statement, the Base
      Prospectus and the Prospectus Supplement and the grant of options under
      existing stock option plans described in the Registration Statement, the
      Base Prospectus and the Prospectus Supplement) or outstanding indebtedness
      of the Company or (v) any dividend or distribution of any kind declared,
      paid or made on the capital stock of the Company.

      (kk)  Any statistical and market-related data included in the Registration
      Statement, the Base Prospectus or the Prospectus Supplement are based on
      or derived from sources that the Company believes to be reliable and
      accurate, and the Company has obtained the written consent to the use of
      such data from such sources to the extent required.

      (ll)  The Stock is registered under the Exchange Act and is duly listed
      and admitted and authorized for trading, subject to official notice of
      issuance, on the Nasdaq National Market ("Nasdaq") and the Company has
      taken no action designed to, or likely to have the effect of terminating
      the registration of the Common Stock under the Exchange Act or delisting
      or suspending from trading the Common Stock from Nasdaq, nor has the
      Company received from the National Association of Securities Dealers, Inc.
      ("NASD") notice that the NASD is contemplating terminating or suspending
      such registration or listing.

      (mm)  Neither the Company nor any of its subsidiaries nor any of their
      officers, directors or affiliates has taken or will take, directly or
      indirectly, any action designed or intended to stabilize or manipulate the
      price of any security of the Company, or which caused or resulted in, or
      which would in the future reasonably be expected to cause or result in,
      stabilization or manipulation of the price of any security of the Company.

                                       13


      (nn)  To the best of the Company's knowledge, there are no affiliations
      with the NASD among the Company's officers, directors or any five percent
      or greater stockholder of the Company, except as set forth in the Base
      Prospectus, the Prospectus Supplement or the Registration Statement or
      otherwise disclosed in writing to the Placement Agent.

      (oo)  The Company satisfies the pre-1992 eligibility requirements for the
      use of a Registration Statement on Form S-3 in connection with the
      Offering contemplated thereby (the pre-1992 eligibility requirements for
      the use of the Registration Statement on Form S-3 include (i) having a
      non-affiliate, public common equity float of at least $150 million or a
      non-affiliate, public common equity float of at least $100 million and
      annual trading volume of at least three million shares and (ii) having
      been subject to the Exchange Act reporting requirements for a period of 36
      months).

      Any certificate signed by any officer of the Company and delivered to the
Placement Agent or counsel for the Placement Agent in connection with the
offering of the Stock shall be deemed a representation and warranty by the
Company and its subsidiaries, as to the matters covered thereby, to the
Placement Agent and the Purchasers.

3.    THE CLOSING. The time and date of closing and delivery of the documents
required to be delivered to the Placement Agent pursuant to Section 6 hereof
shall be at 9:00 A.M., local time, on May 14, 2004 (the "CLOSING DATE") at the
office of Heller Ehrman White & McAuliffe LLP, 4350 La Jolla Village Drive, 7th
Floor, San Diego, California.

4.    FURTHER AGREEMENTS OF THE COMPANY. The Company agrees with the Placement
Agent and the Purchasers:

      (a) (i) to make no further amendment or supplement prior to the Closing
      Date to the Registration Statement or any amendment or supplement to the
      Prospectus Supplement, without the prior written consent of the Placement
      Agent, which consent shall not be unreasonably withheld; (ii) for so long
      as the delivery of a prospectus is required in connection with the
      offering or sale of the Stock, to advise the Placement Agent promptly
      after it receives notice thereof, of the time when any amendment to the
      Registration Statement has been filed or becomes effective or any
      supplement to the Prospectus Supplement or any amended Prospectus
      Supplement has been filed and to furnish the Placement Agent with copies
      thereof; (iii) subsequent to the date of the Prospectus Supplement and for
      so long as the delivery of a prospectus is required in connection with the
      offering or sale of the Stock, to use its commercially reasonable efforts
      to file promptly all reports and any definitive proxy or information
      statements required to be filed by the Company with the Commission and
      Nasdaq pursuant to Section 13(a), 15 or 15(d) of the Exchange Act; (iv) to
      advise the Placement Agent, promptly after it receives notices thereof,
      (x) of any request by the Commission to amend the Registration Statement
      or to amend or supplement the Prospectus Supplement or for additional
      information and (y) of the issuance by the Commission, of any stop order
      suspending the effectiveness of the Registration Statement or any
      post-effective amendment thereto or any order directed at any

                                       14


      Incorporated Document or any amendment or supplement thereto or any order
      preventing or suspending the use of the Base Prospectus or the Prospectus
      Supplement or any amendment or supplement thereto, of the suspension of
      the qualification of the Stock for offering or sale in any jurisdiction,
      of the institution or threatening of any proceeding for any such purpose,
      or of any request by the Commission for the amending or supplementing of
      the Registration Statement or Prospectus Supplement or for additional
      information; and, (v) in the event of the issuance of any stop order or of
      any order preventing or suspending the use of the Base Prospectus or
      Prospectus Supplement or suspending any such qualification, promptly to
      use its reasonable best efforts to obtain the withdrawal of such order.

      (b)   To comply with the Securities Act and the Exchange Act, and the
      Rules and Regulations thereunder, so as to permit the completion of the
      distribution of the Stock as contemplated in this Agreement and the
      Prospectus Supplement. If during the period in which a prospectus is
      required by law to be delivered by a Placement Agent or a dealer in
      connection with the distribution of Stock contemplated by the Prospectus
      Supplement, any event shall occur as a result of which, in the judgment of
      the Company or in the reasonable opinion of the Placement Agent or counsel
      for the Placement Agent, it becomes necessary to amend or supplement the
      Prospectus Supplement in order to make the statements therein, in the
      light of the circumstances existing at the time the Prospectus Supplement
      is delivered to a purchaser, not misleading, or, if it is necessary at any
      time to amend or supplement the Prospectus Supplement to comply with any
      law, the Company promptly will prepare and file with the Commission, and
      furnish at its own expense to the Placement Agent and to dealers, an
      appropriate amendment to the Registration Statement or supplement to the
      Prospectus Supplement so that the Prospectus Supplement as so amended or
      supplemented will not, in the light of the circumstances when it is so
      delivered, be misleading, or so that the Prospectus Supplement will comply
      with such law. Before amending the Registration Statement or supplementing
      the Base Prospectus in connection with the Offering, the Company will
      furnish the Placement Agent with a copy of such proposed amendment or
      supplement and will not file such amendment or supplement to which the
      Placement Agent reasonably objects.

      (c)   To furnish promptly to the Placement Agent and to counsel for the
      Placement Agent a copy of the Registration Statement as originally filed
      with the Commission, and each amendment thereto filed with the Commission,
      including all consents and exhibits filed therewith.

      (d)   To deliver promptly to the Placement Agent such number of the
      following documents as the Placement Agent shall reasonably request: (i)
      conformed copies of the Registration Statement as originally filed with
      the Commission and each amendment thereto (in each case excluding
      exhibits), (ii) the Base Prospectus, (iii) the Prospectus Supplement (as
      soon as practicable, but no later than on the second Business Day
      following the execution and delivery of this Agreement) and any amendment
      or supplement thereto (as soon as practicable, but no later than on the
      second Business Day following the date of such amendment or supplement);
      and (iv) any document

                                       15


      incorporated by reference in the Base Prospectus or Prospectus Supplement.
      The Company will pay the expenses of printing or other production of all
      documents relating to the Offering.

      (e)   To make generally available to its stockholders as soon as
      practicable, but in any event not later than eighteen months after the
      effective date of the Registration Statement (as defined in Rule 158(c)
      under the Securities Act), an earnings statement of the Company (which
      need not be audited) complying with Section 11(a) of the Securities Act
      and the Rules and Regulations (including, at the option of the Company,
      Rule 158).

      (f)   To promptly take from time to time such actions as the Placement
      Agent may reasonably request to qualify the Stock for offering and sale
      under the securities, or blue sky, laws of such jurisdictions (including
      without limitation any post-filing requirements) as the Placement Agent
      may designate and to continue such qualifications in effect for so long as
      required for the distribution of the Stock, and the Company will pay the
      fee of the NASD in connection with its review of the Offering, if
      applicable. The Company shall not be obligated to qualify as a foreign
      corporation in any jurisdiction in which it is not so qualified or to file
      a general consent to service of process in any jurisdiction.

      (g)   Not to directly or indirectly offer, sell, assign, transfer, pledge,
      contract to sell, or otherwise dispose of any shares of Common Stock or
      securities convertible into or exercisable or exchangeable for Common
      Stock for a period of 90 days from the date of the Prospectus Supplement
      without the prior written consent of SG Cowen, other than the Company's
      sale of the Stock, the issuance of Common Stock upon exercise or
      conversion of currently outstanding options, warrants or rights, and the
      issuance of Common Stock, stock options, stock appreciation rights or
      other securities or rights pursuant to the Company's currently existing
      equity compensation plans. The Company will cause each of its executive
      officers and directors to furnish to the Placement Agent, prior to the
      Closing Date, a letter, substantially in the form of Exhibit B attached
      hereto, pursuant to which each such person shall agree not to directly or
      indirectly offer, sell, assign, transfer, pledge, contract to sell, or
      otherwise dispose of any shares of Common Stock or securities convertible
      into or exercisable or exchangeable for Common Stock for a period of 90
      days from the date of the Prospectus Supplement, except for sales made
      pursuant to a written stock selling plan under Rule 10b5-1 of the Exchange
      Act or with the prior written consent of SG Cowen. If (i) the Company
      issues an earnings release or material news or a material event relating
      to the Company occurs during the last 17 days of the lock-up period, or
      (ii) prior to the expiration of the lock-up period, the Company announces
      that it will release earnings results during the 16-day period beginning
      on the last day of the lock-up period, the restrictions imposed by this
      Section 4(g) shall continue to apply until the expiration of the 18-day
      period beginning on the issuance of the earnings release or the occurrence
      of the material news or material event.

      (h)   Prior to the Closing Date, to furnish to the Placement Agent, as
      soon as they have been prepared, copies of any unaudited interim
      consolidated

                                       16


      financial statements of the Company for any periods subsequent to the
      periods covered by the financial statements appearing or incorporated by
      reference in the Base Prospectus, the Prospectus Supplement or the
      Registration Statement.

      (i)   Prior to the Closing Date, not to issue any press release or other
      communication directly or indirectly or hold any press conference with
      respect to the Company, its condition, financial or otherwise, or
      earnings, business affairs or business prospects (except for routine oral
      marketing communications in the ordinary course of business and consistent
      with the past practices of the Company and of which the Placement Agent is
      notified), without the prior written consent of the Placement Agent,
      unless in the judgment of the Company and its counsel, and after
      notification to the Placement Agent, such press release or communication
      is required by law. In such event, the Company shall consult with the
      Placement Agent as to the contents of such press release.

      (j)   To apply the net proceeds from the sale of the Stock as set forth in
      the Prospectus Supplement under the heading "USE OF PROCEEDS."

      (k)   To comply in all material respects with all applicable securities
      and other applicable laws, rules and regulations, including, without
      limitation, the Sarbanes-Oxley Act, and use its best efforts to cause the
      Company's directors and officers, in their capacities as such, to comply
      with such laws, rules and regulations, including, without limitation, the
      provisions of the Sarbanes-Oxley Act.

      (l)   To engage and maintain, at its expense, a registrar and transfer
      agent for the Stock.

      (m)   To not take any action prior to the Closing Date which would require
      the Prospectus Supplement to be amended or supplemented pursuant to
      Section 4(b).

      (n)   To supply the Placement Agent with copies of all correspondence to
      and from, and all documents issued to and by, the Commission in connection
      with the registration of the Stock under the Securities Act.

      (o)   To use its best efforts to ensure that the Stock is quoted on the
      Nasdaq National Market at the Closing Date.

5.    PAYMENT OF EXPENSES. The Company agrees with the Placement Agent to pay
(a) the costs incident to the authorization, issuance, sale, preparation and
delivery of the Stock to the Purchasers and any taxes payable in that
connection; (b) the costs incident to the Registration of the Stock under the
Securities Act; (c) the costs incident to the preparation, printing and
distribution of the Registration Statement, Base Prospectus and Prospectus
Supplement and any amendments and exhibits thereto or any document incorporated
by reference therein, and the costs of printing, reproducing and distributing,
this Agreement by mail, telex or other means of communication; (d) the fees and
expenses incurred in connection with filings, if any, made with the NASD, if
applicable; (e) any applicable listing or other fees; (f) the fees and expenses
of qualifying the Stock under the securities laws of the several

                                       17


jurisdictions as provided in Section 4(f) and of preparing, printing and
distributing Blue Sky Memoranda (including related reasonable fees and expenses
of counsel to the Placement Agent); (g) all fees and expenses of the registrar
and transfer agent of the Stock; and (h) all other costs and expenses incident
to the performance of the obligations of the Company under this Agreement
(including, without limitation, the fees and expenses of the Company's counsel
and the Company's independent accountants and the travel and other expenses
incurred by Company personnel in connection with any "roadshow" including,
without limitation, any expenses advanced by the Placement Agent on the
Company's behalf (which will be promptly reimbursed)); provided that, except as
otherwise provided in this Section 5 and in Sections 7 and 9, the Placement
Agent shall pay its own costs and expenses, including the fees and expenses of
its counsel.

6.    CONDITIONS TO THE OBLIGATIONS OF THE PLACEMENT AGENT AND THE PURCHASERS,
AND THE SALE OF THE STOCK. The respective obligations of the Placement Agent and
the Purchasers, and the closing of the sale of the Stock hereunder are subject
to the accuracy, when made and on the Closing Date, of the representations and
warranties on the part of the Company and its subsidiaries contained herein, to
the accuracy of the statements of the Company and its subsidiaries made in any
certificates pursuant to the provisions hereof, to the performance by the
Company and its subsidiaries of their obligations hereunder, and to each of the
following additional terms and conditions:

      (a)   No stop order suspending the effectiveness of the Registration
      Statement shall have been issued and no proceedings for that purpose shall
      have been initiated or threatened by the Commission, and any request for
      additional information on the part of the Commission (to be included in
      the Registration Statement, the Base Prospectus or the Prospectus
      Supplement or otherwise) shall have been complied with to the reasonable
      satisfaction of the Placement Agent. Any filings required to be made by
      the Company in accordance with Section 4(a) shall have been timely filed
      with the Commission.

      (b)   The Placement Agent shall not have discovered and disclosed to the
      Company on or prior to the Closing Date that the Registration Statement,
      the Base Prospectus or the Prospectus Supplement or any amendment or
      supplement thereto contains an untrue statement of a fact which, in the
      opinion of counsel for the Placement Agent, is material or omits to state
      any fact which, in the opinion of such counsel, is material and is
      required to be stated therein or is necessary to make the statements
      therein not misleading.

      (c)   All corporate proceedings and other legal matters incident to the
      authorization, form, execution, delivery and validity of each of this
      Agreement, the Stock, the Registration Statement, the Base Prospectus and
      the Prospectus Supplement and all other legal matters relating to this
      Agreement and the transactions contemplated hereby shall be reasonably
      satisfactory in all material respects to counsel for the Placement Agent,
      and the Company shall have furnished to such counsel all documents and
      information that they may reasonably request to enable them to pass upon
      such matters.

                                       18


      (d)   The Placement Agent shall have received from Heller Ehrman White &
      McAuliffe LLP, corporate counsel for the Company; such counsel's written
      opinion, addressed to the Placement Agent and the Purchasers and dated as
      of the Closing Date, in form and substance reasonably satisfactory to the
      Placement Agent as set forth in Exhibit C-1 attached hereto.

      (e)   The Company shall have furnished to the Placement Agent a
      certificate addressed to the Placement Agent and the Purchasers, dated as
      of the Closing Date, executed by its Vice President of Intellectual
      Property, in form and substance reasonably satisfactory to the Placement
      Agent as set forth in Exhibit C-2 attached hereto.

      (f)   The Placement Agent shall have received from Brown Raysman Millstein
      Felder & Steiner LLP, such opinion or opinions, dated the Closing Date and
      addressed to the Placement Agent, with respect to the issuance and sale of
      the Stock, the Registration Statement, the Base Prospectus, the Prospectus
      Supplement (together with any supplement thereto) and other related
      matters as the Placement Agent may reasonably require, and the Company
      shall have furnished to such counsel such documents as they request for
      the purpose of enabling them to pass upon such matters.

      (g)   The Company shall have furnished to the Placement Agent and the
      Purchasers a certificate, dated as of the Closing Date, executed by its
      Chairman of the Board, its Chief Executive Officer or a Vice President and
      its Chief Financial Officer stating that (i) such officers have carefully
      examined the Registration Statement, the Base Prospectus and the
      Prospectus Supplement and, in their opinion, the Registration Statement
      (including the Base Prospectus) as of its effective date and the
      Prospectus Supplement, as of each such effective date, did not include any
      untrue statement of a material fact and did not omit to state a material
      fact required to be stated therein or necessary to make the statements
      therein not misleading, (ii) since the effective date of the Registration
      Statement no event has occurred which should have been set forth in a
      supplement or amendment to the Registration Statement, the Base Prospectus
      or the Prospectus Supplement, (iii) to the best of their knowledge after
      reasonable investigation, as of the Closing Date, the representations and
      warranties of the Company and its subsidiaries in this Agreement are true
      and correct and the Company and its subsidiaries have complied in all
      material respects with all agreements and covenants contained in this
      Agreement and satisfied all conditions on its part to be performed or
      satisfied hereunder at or prior to the Closing Date, (iv) subsequent to
      the date of the most recent financial statements included or incorporated
      by reference in the Base Prospectus and the Prospectus Supplement, there
      has been no change in the financial position or results of operation of
      the Company and its subsidiaries that would have a Material Adverse
      Effect, or any material change, or any material development including a
      prospective change, in or affecting the condition (financial or
      otherwise), results of operations, business or prospects of the Company
      and its subsidiaries taken as a whole, except as set forth in the Base
      Prospectus and the Prospectus Supplement, and (v) the Registration
      Statement is effective, and to their knowledge, as of the Closing Date (I)
      no stop order suspending the effectiveness of the Registration

                                       19


      Statement has been issued and no proceedings for that purpose have been
      commenced or are pending before or are contemplated by the Commission and
      (II) no action has been taken by any governmental agency, body or
      official, and no injunction, restraining order or order of any nature by
      any federal or state court has been issued, which would prevent the
      issuance of the Stock.

      (h)   At the time of the execution of this Agreement, the Placement Agent
      shall have received from Ernst & Young LLP a letter, addressed to the
      Placement Agent dated such date, in form and substance reasonably
      satisfactory to the Placement Agent (i) confirming that they are
      independent certified public accountants with respect to the Company
      within the meaning of the Securities Act and the Rules and Regulations and
      (ii) stating the conclusions and findings of such firm with respect to the
      financial statements and certain financial information contained or
      incorporated by reference in the Base Prospectus and the Prospectus
      Supplement.

      (i)   On the Closing Date, the Placement Agent shall have received a
      letter (the "BRING-DOWN LETTER") from Ernst & Young LLP addressed to the
      Placement Agent and dated the Closing Date confirming, as of the date of
      the bring-down letter (or, with respect to matters involving changes or
      developments since the respective dates as of which specified financial
      information is given in the Base Prospectus and the Prospectus Supplement
      as of a date not more than three Business Days prior to the date of the
      bring-down letter), the conclusions and findings of such firm with respect
      to the financial information and other matters covered by its letter
      delivered to the Placement Agent concurrently with the execution of this
      Agreement pursuant to Section 6(h).

      (j)   (i) Neither the Company nor any of its subsidiaries shall have
      sustained since the date of the latest audited financial statements
      included or incorporated by reference in the Base Prospectus and the
      Prospectus Supplement any loss or interference with its business from
      fire, explosion, flood, terrorist act or other calamity, whether or not
      covered by insurance, or from any labor dispute or court or governmental
      action, order or decree, otherwise than as set forth in or contemplated by
      the Base Prospectus and the Prospectus Supplement, and (ii) since such
      date there shall not have been any change in the capital stock or
      long-term debt of the Company or any of its subsidiaries or any change, or
      any development involving a prospective change, in or affecting the
      business, general affairs, management, financial position, stockholders'
      equity, results of operations or prospects of the Company and its
      subsidiaries, otherwise than as set forth in or contemplated by the Base
      Prospectus and the Prospectus Supplement, the effect of which, in any such
      case described in clause (i) or (ii), is, in the judgment of the Placement
      Agent, so material and adverse as to make it impracticable or inadvisable
      to proceed with the sale or delivery of the Stock on the terms and in the
      manner contemplated by the Base Prospectus and the Prospectus Supplement.

      (k)   The Stock is registered under the Exchange Act and, as of the
      Closing Date, shall be listed and admitted and authorized for trading on
      the Nasdaq National Market, and satisfactory evidence of such actions
      shall have been

                                       20


      provided to the Placement Agent. The Company shall have taken no action
      designed to, or likely to have the effect of terminating the registration
      of the Stock under the Exchange Act or delisting or suspending from
      trading the Stock from Nasdaq, nor has Nasdaq notified the Company that it
      is contemplating terminating such registration or listing.

      (l)   At the Execution Time, the Company shall have furnished to the
      Placement Agent a letter substantially in the form of Exhibit B hereto
      from each executive officer and director of the Company.

      (m)   Subsequent to the execution and delivery of this Agreement, there
      shall not have occurred any of the following: (i) trading in securities
      generally on the New York Stock Exchange, the Nasdaq National Market or
      the American Stock Exchange or in the over-the-counter market, or trading
      in any securities of the Company on any exchange or in the
      over-the-counter market, shall have been suspended or minimum or maximum
      prices or maximum ranges for prices shall have been established on any
      such exchange or such market by the Commission, by such exchange or by any
      other regulatory body or governmental authority having jurisdiction, (ii)
      a banking moratorium shall have been declared by Federal or state
      authorities or a material disruption has occurred in commercial banking or
      securities settlement or clearance services in the United States, (iii)
      the United States shall have become engaged in hostilities in which it is
      not currently engaged, or the subject of an act of terrorism, there shall
      have been an escalation in existing hostilities involving the United
      States or there shall have been a declaration of a national emergency or
      war by the United States or (iv) there shall have occurred such a material
      adverse change in general economic, political or financial conditions in
      the United States (or the effect of international conditions on the
      financial markets in the United States shall be such) as to make it, in
      the case of any such event in clause (iii) or (iv), in the sole judgment
      of the Placement Agent, impracticable or inadvisable to proceed with the
      sale or delivery of the Stock on the terms and in the manner contemplated
      by the Base Prospectus and the Prospectus Supplement.

      (n)   No action shall have been taken and no statute, rule, regulation or
      order shall have been enacted, adopted or issued by any governmental
      agency or body which would, as of the Closing Date, prevent the issuance
      or sale of the Stock; and no injunction, restraining order or order of any
      other nature by any federal or state court of competent jurisdiction shall
      have been issued as of the Closing Date which would prevent the issuance
      or sale of the Stock.

      (o)   The Company shall have prepared and filed with the Commission a
      Current Report on Form 8-K with respect to the Offering, including as an
      exhibit thereto this Agreement and any other documents relating thereto.

      (p)   The Company shall have entered into Subscription Agreements with
      each of the Purchasers and such agreements shall be in full force and
      effect.

      (q)   Prior to the Closing Date, the Company shall have furnished to SG
      Cowen such further information, certificates and documents as SG Cowen may
      reasonably request.

                                       21


      All opinions, letters, evidence and certificates mentioned above or
elsewhere in this Agreement shall be deemed to be in compliance with the
provisions hereof only if they are in form and substance reasonably satisfactory
to counsel for the Placement Agent.

7.    INDEMNIFICATION AND CONTRIBUTION.

      (a)   The Company shall indemnify and hold harmless the Placement Agent,
      its officers, employees, representatives and agents and each person, if
      any, who controls the Placement Agent within the meaning of the Securities
      Act (collectively the "PLACEMENT AGENT INDEMNIFIED Parties" and each a
      "PLACEMENT AGENT INDEMNIFIED PARTY") against any loss, claim, damage or
      liability, joint or several, or any action in respect thereof, to which
      that Placement Agent Indemnified Party may become subject, under the
      Securities Act or otherwise, insofar as such loss, claim, damage,
      liability or action arises out of or is based upon (i) any untrue
      statement or alleged untrue statement of a material fact contained in the
      Base Prospectus, the Registration Statement or the Prospectus Supplement
      or in any amendment or supplement thereto, (ii) the omission or alleged
      omission to state in the Base Prospectus, the Registration Statement or
      the Prospectus Supplement or in any amendment or supplement thereto a
      material fact required to be stated therein or necessary to make the
      statements therein not misleading, and shall reimburse each Placement
      Agent Indemnified Party promptly upon demand for any legal or other
      expenses reasonably incurred by that Placement Agent Indemnified Party in
      connection with investigating or preparing to defend or defending against
      or appearing as a third party witness in connection with any such loss,
      claim, damage, liability or action as such expenses are incurred;
      provided, however, that the Company shall not be liable in any such case
      to the extent that any such loss, claim, damage, liability or action
      arises out of or is based upon an untrue statement or alleged untrue
      statement in or omission or alleged omission from the Base Prospectus, the
      Registration Statement or the Prospectus Supplement or any such amendment
      or supplement in reliance upon and in conformity with written information
      furnished to the Company through the Placement Agent specifically for use
      therein, which information the parties hereto agree is limited to the
      Placement Agent's Information (as defined in Section 15). This indemnity
      agreement is not exclusive and will be in addition to any liability, which
      the Company might otherwise have and shall not limit any rights or
      remedies which may otherwise be available at law or in equity to each
      Placement Agent Indemnified Party.

      (b)   The Placement Agent shall indemnify and hold harmless the Company
      its officers, employees, representatives and agents, each of its directors
      and each person, if any, who controls the Company within the meaning of
      the Securities Act (collectively the "COMPANY INDEMNIFIED PARTIES" and
      each a "COMPANY INDEMNIFIED PARTY") against any loss, claim, damage or
      liability, joint or several, or any action in respect thereof, to which
      the Company Indemnified Parties may become subject, under the Securities
      Act or otherwise, insofar as such loss, claim, damage, liability or action
      arises out of or is based upon (i) any untrue statement or alleged untrue
      statement of a material fact contained in the Base Prospectus, the
      Registration Statement or

                                       22


      the Prospectus Supplement or in any amendment or supplement thereto or
      (ii) 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, but in each case only to the extent that the untrue
      statement or alleged untrue statement or omission or alleged omission was
      made in reliance upon and in conformity with written information furnished
      to the Company through the Placement Agent specifically for use therein,
      and shall reimburse the Company Indemnified Parties for any legal or other
      expenses reasonably incurred by such parties in connection with
      investigating or preparing to defend or defending against or appearing as
      third party witness in connection with any such loss, claim, damage,
      liability or action as such expenses are incurred; provided that the
      parties hereto hereby agree that such written information provided by the
      Placement Agent consists solely of the Placement Agent's Information. This
      indemnity agreement is not exclusive and will be in addition to any
      liability, which the Placement Agent and the Purchasers might otherwise
      have and shall not limit any rights or remedies which may otherwise be
      available at law or in equity to the Company Indemnified Parties.
      Notwithstanding the provisions of this Section 7(b), in no event shall any
      indemnity under this Section 7(b) exceed the total compensation received
      by the Placement Agent in accordance with Section 1(e).

      (c)   Promptly after receipt by an indemnified party under this Section 7
      of notice of any claim or the commencement of any action, the indemnified
      party shall, if a claim in respect thereof is to be made against the
      indemnifying party under this Section 7, notify the indemnifying party in
      writing of the claim or the commencement of that action; provided,
      however, that the failure to notify the indemnifying party shall not
      relieve it from any liability which it may have under this Section 7
      except to the extent it has been materially prejudiced by such failure;
      and, provided, further, that the failure to notify the indemnifying party
      shall not relieve it from any liability which it may have to an
      indemnified party otherwise than under this Section 7. If any such claim
      or action shall be brought against an indemnified party, and it shall
      notify the indemnifying party thereof, the indemnifying party shall be
      entitled to participate therein and, to the extent that it wishes, jointly
      with any other similarly notified indemnifying party, to assume the
      defense thereof with counsel reasonably satisfactory to the indemnified
      party. After notice from the indemnifying party to the indemnified party
      of its election to assume the defense of such claim or action, the
      indemnifying party shall not be liable to the indemnified party under this
      Section 7 for any legal or other expenses subsequently incurred by the
      indemnified party in connection with the defense thereof other than
      reasonable costs of investigation; provided, however, that any indemnified
      party shall have the right to employ separate counsel in any such action
      and to participate in the defense thereof but the fees and expenses of
      such counsel shall be at the expense of such indemnified party unless (i)
      the employment thereof has been specifically authorized by the
      indemnifying party in writing, (ii) such indemnified party shall have been
      advised by such counsel that there may be one or more legal defenses
      available to it which are different from or additional to those available
      to the indemnifying party and in the reasonable judgment of such counsel
      it is advisable for such indemnified party to employ separate counsel or
      (iii) the indemnifying party has failed to

                                       23


      assume the defense of such action in accordance with the terms hereof and
      employ counsel reasonably satisfactory to the indemnified party, in which
      case, if such indemnified party notifies the indemnifying party in writing
      that it elects to employ separate counsel at the expense of the
      indemnifying party, the indemnifying party shall not have the right to
      assume the defense of such action on behalf of such indemnified party, it
      being understood, however, that the indemnifying party shall not, in
      connection with any one such action or separate but substantially similar
      or related actions in the same jurisdiction arising out of the same
      general allegations or circumstances, be liable for the reasonable fees
      and expenses of more than one separate firm of attorneys at any time for
      all such indemnified parties, which firm shall be designated in writing by
      the Placement Agent, if the indemnified parties under this Section 7
      consist of any Placement Agent Indemnified Party, or by the Company if the
      indemnified parties under this Section 7 consist of any Company
      Indemnified Parties. Each indemnified party, as a condition of the
      indemnity agreements contained in Sections 7(a) and 7(b) shall use all
      reasonable efforts to cooperate with the indemnifying party in the defense
      of any such action or claim. Subject to the provisions of Section 7(d)
      below, no indemnifying party shall be liable for any settlement,
      compromise or consent to the entry of judgment in connection with any such
      action effected without its written consent (which consent shall not be
      unreasonably withheld), but if settled with its written consent or if
      there be a final judgment for the plaintiff in any such action (other than
      a judgment entered with the consent of such indemnified party), the
      indemnifying party agrees to indemnify and hold harmless any indemnified
      party from and against any loss or liability by reason of such settlement
      or judgment.

      (d)   If at any time an indemnified party shall have requested that an
      indemnifying party reimburse the indemnified party for fees and expenses
      of counsel, such indemnifying party agrees that it shall be liable for any
      settlement of the nature contemplated by this Section 7 effected without
      its written consent if (i) such settlement is entered into more than 45
      days after receipt by such indemnifying party of the request for
      reimbursement, (ii) such indemnifying party shall have received notice of
      the terms of such settlement at least 30 days prior to such settlement
      being entered into and (iii) such indemnifying party shall not have
      reimbursed such indemnified party in accordance with such request prior to
      the date of such settlement.

      (e)   If the indemnification provided for in this Section 7 is unavailable
      or insufficient to hold harmless an indemnified party under Section 7(a)
      or 7(b), then each indemnifying party shall, in lieu of indemnifying such
      indemnified party, contribute to the amount paid or payable by such
      indemnified party as a result of such loss, claim, damage or liability, or
      action in respect thereof, (i) in such proportion as shall be appropriate
      to reflect the relative benefits received by the Company on the one hand
      and the Placement Agent on the other from the offering of the Stock 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 Placement Agent on
      the other with respect to the statements or omissions

                                       24


      which resulted in such loss, claim, damage or liability, or action in
      respect thereof, as well as any other relevant equitable considerations.
      The relative benefits received by the Company on the one hand and the
      Placement Agent on the other with respect to such offering shall be deemed
      to be in the same proportion as the total net proceeds from the offering
      of the Stock purchased under this Agreement (before deducting expenses)
      received by the Company bears to the total compensation received by the
      Placement Agent with respect to the Stock purchased under this Agreement.
      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 on the one hand or the Placement Agent
      on the other, the intent of the parties and their relative knowledge,
      access to information and opportunity to correct or prevent such untrue
      statement or omission; provided that the parties hereto agree that the
      written information furnished to the Company by the Placement Agent for
      use in the Prospectus Supplement consists solely of the Placement Agent's
      Information. The Company and the Placement Agent agree that it would not
      be just and equitable if contributions pursuant to this Section 7(e) were
      to be determined by pro rata allocation or by any other method of
      allocation which does not take into account the equitable considerations
      referred to herein. The amount paid or payable by an indemnified party as
      a result of the loss, claim, damage or liability, or action in respect
      thereof, referred to above in this Section 7(e) shall be deemed to
      include, for purposes of this Section 7(e), any legal or other expenses
      reasonably incurred by such indemnified party in connection with
      investigating or defending any such action or claim. Notwithstanding the
      provisions of this Section 7(e), the Placement Agent shall not be required
      to contribute any amount in excess of (x) the aggregate total price at
      which the Stock was sold to the Purchasers less (y) the amount of any
      damages which such Placement Agent has otherwise paid or become liable to
      pay by reason of any 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 Securities Act) shall be entitled to
      contribution from any person who was not guilty of such fraudulent
      misrepresentation.

8.    TERMINATION. The obligations of the Placement Agent and the Purchasers
hereunder and under the Subscription Agreements may be terminated by the
Placement Agent, in its absolute discretion by notice given to the Company prior
to delivery (including electronic delivery) of and payment for the Stock if,
prior to that time, any of the events described in Sections 6(j) or 6(m) have
occurred or if the Purchasers shall decline to purchase the Stock for any reason
permitted under this Agreement.

9.    REIMBURSEMENT OF PLACEMENT AGENT'S EXPENSES. If the sale of the Stock
provided for herein is not consummated because any condition to the obligations
of the Placement Agent and the Purchasers set forth in Section 6 hereof is not
satisfied, because of any termination pursuant to Section 8 hereof or because of
any refusal, inability or failure on the part of the Company to perform any
agreement herein or comply with any provision hereof other than by reason of a
default by the Placement Agent, the Company will reimburse the Placement Agent
upon demand for all

                                       25


reasonable out-of-pocket expenses (including reasonable fees and disbursements
of counsel and any expenses advanced by the Placement Agent on the Company's
behalf) that shall have been incurred by the Placement Agent in connection with
this Agreement and the proposed purchase and sale of the Stock and, upon demand,
the Company shall pay the full amount thereof to SG Cowen.

10.   SUCCESSORS; PERSONS ENTITLED TO BENEFIT OF AGREEMENT. This Agreement shall
inure to the benefit of and be binding upon the Placement Agent, the Purchasers,
the Company, and their respective successors. Nothing expressed or mentioned in
this Agreement is intended or shall be construed to give any person other than
the persons mentioned in the preceding sentence any legal or equitable right,
remedy or claim under or in respect of this Agreement, or any provisions herein
contained, this Agreement and all conditions and provisions hereof being
intended to be and being for the sole and exclusive benefit of such persons and
for the benefit of no other person; except that the representations, warranties,
covenants, agreements and indemnities of the Company contained in this Agreement
shall also be for the benefit of the Placement Agent Indemnified Parties, and
the indemnities of the Placement Agent shall also be for the benefit of the
Company Indemnified Parties. It is understood that the Placement Agent's
responsibilities to the Company are solely contractual in nature and the
Placement Agent does not owe the Company, or any other party, any fiduciary duty
as a result of this Agreement.

11.   SURVIVAL OF INDEMNITIES, REPRESENTATIONS, WARRANTIES, ETC. The respective
indemnities, covenants, agreements, representations, warranties and other
statements of the Company and the Placement Agent, as set forth in this
Agreement or made by them respectively, pursuant to this Agreement, shall remain
in full force and effect, regardless of any investigation made by or on behalf
of the Placement Agent, the Company, the Purchasers or any person controlling
any of them and shall survive delivery of and payment for the Stock.

12.   NOTICES. All statements, requests, notices and agreements hereunder shall
be in writing, and:

      (a)   if to the Placement Agent, shall be delivered or sent by mail, telex
      or facsimile transmission to SG Cowen & Co., LLC, 1221 Avenue of the
      Americas, New York, New York 10020, Attention: Veronica Iuliano, Esq.
      (Fax: 212-278-7995), with a copy to: Brown Raysman Millstein Felder &
      Steiner LLP, 900 Third Avenue, New York, New York 10022, Attention: Stuart
      Bressman, Esq. (Fax: 212-895-2900).

      (b)   if to the Company shall be delivered or sent by mail, telex or
      facsimile transmission to Illumina, Inc., 9885 Towne Centre Drive, San
      Diego, California 92121, Attention: Jay T. Flatley (Fax: 858-202-4545),
      with a copy to: Heller Ehrman White & McAuliffe LLP, 2775 Sand Hill Road,
      Menlo Park, California 94025, Attention: Edward Y. Kim, Esq. (Fax:
      650-324-0638).

13.   DEFINITIONS OF CERTAIN TERMS. The terms which follow, when used in this
Agreement, shall have the meanings indicated.

            "BUSINESS DAY" shall mean any day other than a Saturday, a Sunday, a
      legal holiday, a day on which banking institutions or trust companies are

                                       26


      authorized or obligated by law to close in New York City or any day on
      which the Nasdaq National Market is not open for trading.

            "EFFECTIVE DATE" shall mean each date and time that the Registration
      Statement (and any post-effective amendment or amendments thereto) became
      or becomes effective.

            "EXECUTION TIME" shall mean the date and time that this Agreement is
      executed and delivered by the parties hereto.

            "INTERFERENCE PROCEEDING" shall have the meaning set forth in 35
      U.S.C. Section 135.

            "TO THE COMPANY'S KNOWLEDGE" and words of similar import shall mean
      that which the Company knows or should have known using the exercise of
      reasonable due diligence.

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

15.   PLACEMENT AGENT'S INFORMATION. The parties hereto acknowledge and agree
that, for all purposes of this Agreement, the Placement Agent's Information
consists solely of the statements concerning the Placement Agent contained in
the third paragraph under the heading "Plan of Distribution" in the Prospectus
Supplement.

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

17.   GENERAL. This Agreement constitutes the entire agreement of the parties to
this Agreement and supersedes all prior written or oral and all contemporaneous
oral agreements, understandings and negotiations with respect to the subject
matter hereof. In this Agreement, the masculine, feminine and neuter genders and
the singular and the plural include one another. The section headings in this
Agreement are for the convenience of the parties only and will not affect the
construction or interpretation of this Agreement. This Agreement may be amended
or modified, and the observance of any term of this Agreement may be waived,
only by a writing signed by the Company and the Placement Agent.

18.   COUNTERPARTS. This Agreement may be signed in any number of counterparts,
each of which shall be an original, with the same effect as if the signatures
thereto and hereto were upon the same instrument.

                                       27


      If the foregoing is in accordance with your understanding of the agreement
between the Company and the Placement Agent, kindly indicate your acceptance in
the space provided for that purpose below.

                                             Very truly yours,

                                             ILLUMINA, INC.

                                             By: /s/ JAY T. FLATLEY
                                                 --------------------
                                             Name: Jay T. Flatley
                                             Title: Chief Executive Officer

Accepted as of
the date first above written:

SG COWEN & CO., LLC

By:   /s/ RICHARD E. GORMLEY
      ----------------------
      Name: Richard E. Gormley
      Title: Managing Director

                                       28