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RISK FACTORS

        Investing in our common stock involves a high degree of risk. You should carefully consider the following risk factors, as well as the other information in this prospectus, before deciding whether to invest in shares of our common stock. The occurrence of any of the events or circumstances described below or other adverse events could harm our business, financial condition, results of operations and growth prospects. If such an event or circumstance were to occur, the trading price of our common stock may decline and you may lose all or part of your investment. Additional risks or uncertainties not presently known to us or that we currently deem immaterial may also harm our business.

Risks Related to Our Financial Condition and Business

We have a limited operating history, which makes it difficult for investors to evaluate our current business and future prospects.

        We were incorporated in June 2004 and do not have a long history of operating results on which you can base your evaluation of our business. We are still proving our business model, and we have not yet demonstrated our ability to generate significant revenue, particularly licensing and royalty revenue. As a result, it may be difficult for public market analysts and investors to evaluate our future prospects. If we do not generate significant licensing and royalty revenue, we may never be profitable. Furthermore, because of our limited operating history and because the semiconductor and clean-energy industries are rapidly evolving, we have limited experience in analyzing and understanding the trends that may emerge and affect our business. If we are unable to obtain significant licensing and royalty revenue from products that incorporate technology developed through our collaborative development programs (CDPs), we will have expended a significant amount of time and resources without obtaining the benefits we anticipated, and our financial condition and results of operations would be materially and adversely affected.

Our operating results may fluctuate from quarter to quarter, which may make it difficult to predict our future performance and may result in volatility in the market price of our common stock if we fail to meet the expectations of public market analysts and investors in these periods.

        Our revenue, expenses and operating results have fluctuated, and may in the future fluctuate significantly from quarter to quarter due to a number of factors, many of which are outside our control. Factors that may contribute to these fluctuations include the following, as well as other factors described elsewhere in this prospectus:

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our dependence on a limited number of customers;



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our ability to manage our growth, including an increasing number of employees, customers and CDPs;



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the length of our sales and development cycles, and our ability to generate material revenue after we have devoted significant resources to developing a project;



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our ability to evolve existing products, anticipate trends in technology development and introduce new developments in a timely manner in the rapidly changing semiconductor and clean-energy industries;



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our customers' ability to manufacture, market and sell products that incorporate technology developed through the CDPs;



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fluctuations in the number and price of products sold by our customers that incorporate technology developed through the CDPs, and the shortening life cycles of those products, in each case impacting our licensing and royalty revenue;

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our ability to scale our development efforts, our ability to secure new CDPs with new or existing customers and the timing of those CDPs;



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the degree to which existing CDPs are completed or expanded;



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one-time, non-cash charges to revenue associated with the vesting of contingent warrants issued to two of our customers that are currently outstanding;



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our ability to maintain existing commercial terms or enter into new licensing arrangements with our customers once they begin to sell their end products;



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our ability to make the substantial research and development (R&D) investments required to stay competitive in our business;



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our ability to develop our high productivity combinatorial (HPC) platform and expertise to support our future growth plans in adjacent vertical markets such as clean-energy markets;



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any potential involvement in intellectual property litigation;



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any potential payments to our customers resulting from our intellectual property indemnification policies and obligations;



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our reliance on our customers to deliver timely and accurate information to accurately report our financial results from licensing and royalty revenue;



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our potential need for additional capital to finance our business;



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any delay in shipments caused by shortages of components incorporated in our customers' products, design errors or other manufacturing problems associated with our customers' products;



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the highly cyclical nature of and price volatility in the semiconductor industry;



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the emerging and uncertain nature of the clean-energy industry;



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potential warranty claims, product recalls and product liability for our HPC tools and for our customers' products that incorporate technology developed through our CDPs;



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global or regional economic, political and social conditions; and



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business interruptions such as earthquakes and other natural disasters.

        Due to these factors and other risks discussed in this section, you should not rely on quarter-to-quarter comparisons to predict our future performance. Our revenue mix may also vary from quarter to quarter as we enter into new CDPs and related customer arrangements, existing CDPs are completed or expanded and licensing and royalty arrangements take effect. Unfavorable changes in any of these factors may adversely affect our business and operating results. Additionally, our common stock could be subject to significant price volatility should our actual or projected revenue or earnings fail to meet the expectations of the investment community. Furthermore, stocks of high technology companies are subject to extreme price and volume fluctuations that are often unrelated or disproportionate to the operating performance of those companies.

We have incurred operating losses since our inception and may not be able to achieve or maintain profitability.

        We have generated net losses each year since our inception, including $3.2 million for the six months ended June 30, 2011 and $1.8 million and $5.3 million for the years ended December 31, 2010 and 2009, respectively. Our accumulated deficit as of June 30, 2011 was $73.2 million. We will need to significantly increase revenue to achieve profitability and we may not achieve or subsequently maintain

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profitability if our revenue increases more slowly than we expect or not at all. Our ability to achieve our objectives and achieve or maintain the profitability of our business will depend, in large part, on potential customers accepting our HPC platform and methodology as effective tools in the development of new products; and on our success in helping our customers develop products that are successful in the marketplace. Historically, semiconductor companies have conducted R&D activities internally using traditional research methods. In order for us to achieve our business objectives, we must convince these companies that our technology and capabilities justify collaborating with us on their basic R&D programs. We must also convince potential customers in the clean-energy industry that our HPC platform and approach are useful tools in an emerging industry. We cannot assure you we will achieve the levels of customer acceptance necessary for us to maintain and grow a profitable business. Our ability to achieve profitability also depends upon many other factors, including many that are beyond our control. These factors include, without limitation:

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changes in the demand for our products and services;



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the introduction of competitive technologies;



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our ability to engage with new customers that would use our technology and expertise to further develop and commercialize their products;



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our ability to enter into CDPs with customers who are or become market leaders;



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the competitiveness and financial strength of our existing and potential customers;



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changes in the R&D budgets of our customers and potential customers;



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our ability to develop our technology for and secure customers in the clean-energy industry; and



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our participation in the development of products that our customers choose to commercialize that generate a substantial stream of licensing and royalty revenue for us.

In addition, we expect to continue to incur significant expenses or revenue adjustments in connection with, among other things:

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increased R&D spending, including expansion of our R&D teams and workflow platforms;



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expansion of our sales and marketing efforts;



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additional non-cash charges relating to amortization of intangibles and deferred stock compensation; and



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one-time, non-cash charges to revenue associated with the vesting of contingent warrants issued to two of our customers that are currently outstanding.

        We cannot assure you we will achieve the levels of customer acceptance necessary for us to maintain and grow a profitable business, or that any of these other factors will be satisfactory. Also, we cannot assure you that customers, even those that accept our HPC platform as a valid tool for R&D, will be satisfied with the integrated devices developed through our CDPs or will be able to successfully commercialize end products incorporating the developed technology. Failure to achieve the necessary customer acceptance or extend or add current or new customer relationships, as well as difficulty with any of these other factors would adversely affect our revenue and profitability and our financial condition and results of operations would be materially and adversely affected.

We depend on a limited number of customers, which have historically been in the semiconductor industry, and a loss of any of them would adversely affect our business and operating results.

        Our customer base is highly concentrated. Revenue has historically come from a few customers, and we expect that revenue from a small number of customers will continue to account for a high

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percentage of our revenue for the foreseeable future. Due to the concentrated nature of manufacturers in the DRAM, flash memory and complex logic markets, our revenue is and may continue to be concentrated among and reliant upon key high-volume customers. For example, our four largest customers in the six months ended June 30, 2011, all of which are in the semiconductor industry, accounted for 75% of our revenue, and our two largest customers for the years ended December 31, 2010 and 2009, both of which are in the semiconductor industry, accounted for 72% and 88% of our revenue, respectively. Our largest customer accounted for 33%, 52% and 59% of our revenue in each of these periods, respectively. The loss of any of these customers or a decrease in the manufacturing or sales volumes of their products, or their failure to pay amounts due to us, and the related impact on our future anticipated licensing and royalty revenue, would materially and adversely affect our business, financial condition or results of operations, and we may not be able to replace the business from these customers. In addition, this type of loss could cause significant fluctuations in our results of operations because our expenses are fixed in the short term and our sales and development cycle to obtain new customers is long.

Our rapid growth has presented significant challenges to our management and administrative systems and resources, and we may experience difficulties managing our growth, particularly as we handle the additional responsibilities of becoming a public company, which could adversely affect our business and operating results.

        We will need to continue to grow in all operational areas and to successfully integrate and support our existing and new employees, which may make it difficult to implement our business strategy in the time frame we anticipate, if at all. Our business has grown rapidly, and we expect this growth to continue as we expand our R&D capacity for current and additional CDPs. For example, we had 190 full-time employees as of June 30, 2011 and 107 employees at the end of 2008. The rapid expansion of our business and addition of new personnel has placed a strain on our management, operational systems and facilities and may continue to do so. To effectively manage our operations and growth as well as our new obligations as a public company, we must continue to expend funds to enhance our operational, financial and management controls, reporting systems and procedures and to attract and retain sufficient numbers of talented employees. If we are unable to expand our R&D capacity and implement improvements to our control systems efficiently and quickly, or if we encounter deficiencies in existing systems and controls, then we will not be able to successfully grow our business as planned. Our future operating results will also depend on our management's ability to:

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implement and improve our sales, marketing and customer support programs and our R&D efforts;



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enhance our operational and financial control systems;



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expand, train and manage our employee base;



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integrate any acquired businesses; and



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effectively address new issues related to our growth as they arise.

We may not manage our expansion successfully, which could adversely affect our business, financial condition or results of operations.

Our business prospects and future growth depend on royalties, which may be difficult to structure and enforce.

        We believe that our royalty-bearing licenses with our customers lay the framework for ongoing royalty revenue from our customers' products that incorporate technology developed through our CDPs with these customers, and that this revenue stream will increase as revenue from products developed using our platform increases. We are dependent upon our ability to structure, negotiate and enforce agreements for the determination and payment of royalties. Unless we adequately demonstrate the value of our platform to our potential customers we may face resistance to structuring royalty

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arrangements in the future that are acceptable to us, or our customers may not agree to enter into royalty-bearing licenses with us at all. If we are unable to maintain the royalty-bearing license aspect of our business model, our operating results would suffer and we may not achieve profitability.

Our sales cycles are long, and we commit significant resources to a project before we have any commitment that a potential customer may agree to use our platform or service. One or more failures to enter into a CDP after we have devoted significant resources to a project could adversely affect our business and operating results.

        Our sales efforts require us to educate our potential customers about the benefits of our solutions, which often requires significant time and expense, including a significant amount of our senior management's time and effort. Our sales cycles to date have typically ranged from 9 to 24 months and may be even longer in the future. Furthermore, we need to target those individuals within a customer's organization who have overall responsibility for the profitability of their products. These individuals tend to be senior management or executive officers. We may face difficulty identifying and establishing contact with these individuals. In addition, our customers' technology and product pipeline are highly confidential and they may choose to withhold certain information from us during the sales cycle to protect their own proprietary technology. Our ability to implement our HPC platform and methodology is heavily dependent upon the information provided to us by our customers. If our customers reveal the complexities of their specifications after we enter into a CDP with them, that complexity may cause delays unanticipated at the time we entered into the program. During our sales cycles, we incur significant expenses and, in many cases, may begin to build, configure or expand new systems, develop software and design workflows to meet our customers' requirements prior to obtaining contractual commitments, without any assurance of resulting revenue. Where a potential customer engagement requires a new dedicated HPC platform, we may invest in new HPC capacity ahead of a customer commitment. Our HPC platform build, configuration and customization cycles to date have ranged from three to nine months and may be even longer in the future. Investment of time and expense in a particular customer engagement that does not ultimately result in material revenue will adversely affect our revenue and results of operations. Other factors impacting sales and the length of our sales and development cycles include, but are not limited to, the following:

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the complexity and cost of our HPC platform and difficulties we may encounter in meeting individual customer specifications and commitments;



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our ability to build, configure or expand new systems, develop software and design workflows to meet our customers' requirements;



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the limited number of customers that are appropriate sales targets for our platform and that are willing to enter into licensing agreements with us;



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our customers' budgetary constraints and internal review procedures that must be completed to begin collaboration with us; and



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the cultural transition required for a customer's internal R&D team to embrace us as a collaborative partner.

The semiconductor industry is rapidly changing and an inability to evolve existing products in a timely manner, anticipate trends in technology development and introduce new technologies could adversely affect our business and operating results.

        We must continually devote significant engineering resources to keep up with the rapidly evolving technologies, materials and equipment used in semiconductor design and manufacturing processes.

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These innovations are inherently complex and require long development cycles. The semiconductor industry is subject to a number of evolving trends, including:

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the growing varieties of semiconductor architecture, applications and processes;



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differing market growth rates and capital requirements for different applications, such as flash memory, DRAM, logic and foundry, and the resulting effect on customers' spending patterns and on our ability to compete in these market segments;



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the importance of growing market positions in larger market segments;



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the increasing consolidation of semiconductor manufacturing towards foundries and large scale manufacturers and subsequent concentration of research and innovation in manufacturing process development; and



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the cost, technical complexity and timing of a proposed industry transition from 300mm to 450mm wafers.

        These and other changes could have a material impact on our business. Not only do we need the technical expertise to implement the changes necessary to keep our technologies current, but we also rely heavily on the judgment of our management and advisors to anticipate future market trends. Our customers expect us to stay ahead of the technology curve in their sectors and expect that the technology developed through our CDPs will help them develop new products that keep pace with or push the limits of technological innovation. If we are not able to accurately predict industry changes, or if we are unable to apply our HPC platform to our customers' needs on a timely basis, our existing solutions will be rendered obsolete and we may lose customers. If we do not keep pace with technology, our existing and potential customers may choose to develop their own solutions internally as an alternative to ours, and we could lose market share to competitors, which could adversely affect our operating results.

The clean-energy industry is in a very early stage of development, and we may not earn significant revenue from our initiatives in this industry for an extended period, if ever.

        Most sectors of the clean-energy industry are in the very early stages of development. Many of the associated technologies have not yet achieved commercial viability in comparison to available alternatives, and may never achieve market adoption. Many of the associated technologies will require substantial investments of capital to achieve scale, which may not be available on attractive terms, if at all. Companies within the clean-energy industry may also be hesitant to enter into CDPs with us given our recent entry into the clean-energy industry. Certain technologies may depend on government subsidies to be commercially viable, and those subsidies may not be available from federal and state governments facing increasing financial constraints. If sectors of the clean-energy industry take an extended period to achieve market acceptance and to garner significant revenue, we may not earn material revenue from our initiatives in this area until such time, if ever. Furthermore, it may be difficult for us to predict which clean-energy companies may become market leaders, and we may invest time and resources in collaborations with companies who are ultimately unsuccessful in the clean-energy industry, which could adversely affect our operating results.

If a project to which we have devoted technology and significant resources fails to produce any measurable success or value to our customers in the form of differentiated technology and intellectual property, we may not earn licensing and royalty revenue sufficient to recover the upfront costs and cash invested in the CDP, which could adversely affect our results of operations.

        In some cases, the revenue we receive from our customers during the development stage is not sufficient for us to fully recover our costs and cash invested in HPC platforms dedicated to customer engagement, and our business model relies on licensing and royalty revenue based on the sales by our

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customers in the end-markets of products incorporating the technology developed through our CDPs. Our CDPs involve complex R&D, and our ability to develop the differentiated technology and intellectual property sought by our customers is inherently uncertain and difficult to predict. In addition, there are a limited number of CDPs to which we can commit our resources at any given time. If a project to which we have devoted technology and significant resources fails to produce any measurable success or value to our customers in the form of differentiated technology and intellectual property that they may use in their products, we may not receive meaningful amounts of, or any, licensing and royalty revenue. In this case, we may not recover the upfront costs and cash invested in the CDP, which could adversely affect our results of operations. In addition, even if we successfully develop differentiated technology and intellectual property through a CDP that our customer is able to commercialize, there may be a significant delay before we receive any licensing or royalty revenue due to the complexities inherent in production and manufacturing in our target markets.

A decline in sales in the end markets for products incorporating technology developed through our CDPs could adversely affect our business and results of operations.

        Our success is tied to our customers' ability to successfully commercialize the products that incorporate technology developed through our CDPs. The markets for our customers' products are intensely competitive and are characterized by rapid technological change. These changes result in frequent product introductions, short product life cycles and increased product capabilities. Competition is based on a variety of factors including price, performance, product quality, software availability, marketing and distribution capability, customer support, name recognition and financial strength. Products incorporating the technology developed through our CDPs may not achieve market success or may become obsolete. We cannot assure you that our customers will dedicate the resources necessary to promote and commercialize products developed through our CDPs, successfully execute their business strategies for such products, be able to manufacture such products in quantities sufficient to meet demand or cost-effectively manufacture products at high volume. Our customers are not contractually obliged to manufacture, distribute or sell any products incorporating our CDP-developed technology. Our customers may develop internally or in collaboration with others technology that they might utilize instead of technology developed through our CDPs. Any of these factors, as well as more general market or industry issues, could result in a decline in sales of the products incorporating our technology, which would result in a decrease in any associated licensing and royalty revenue or the failure of any licensing and royalty revenue to materialize at all, and could adversely affect our business and results of operations. Any failure of a customer to achieve market success for products developed through our CDPs could also negatively affect such customer's willingness to work with us on other collaborations and could more generally harm our reputation and business prospects.

If we are unable to scale our development services and secure new CDPs, our growth prospects would be limited and our business and operating results could be adversely affected.

        Our customers require a significant amount of individualized attention as well as dedicated lab space for CDPs. We have limited space and internal capacity, both in terms of personnel as well as capital equipment resources, to meet these types of demands for our customers. In addition, because of the significant confidentiality concerns associated with the projects and products we work on and the restrictions on resource and information sharing we have implemented in response, we are not able to fully capitalize upon economies of scale. If the demand for our services and products exceeds our capacity to meet such demand, we may be required to turn down potential opportunities, which would cause us to lose potential revenue, and our potential customers may take their business to a competitor or decide to develop or expand internal R&D capabilities. If we are unable to scale our development services to meet demand, our growth may be hindered and our business and operating results could be adversely affected.

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We may not be successful in maintaining and managing CDPs, which would adversely affect our ability to develop successful products and our financial condition and operating results.

        CDPs are complex and time-consuming to implement and they may require substantial resources to maintain. We may not be successful in all of our collaboration efforts and may fail to achieve the technological innovations sought by our customers in a reasonable amount of time or at all. When we collaborate with a customer, we rely to some degree on the efforts and resources of that customer. Our customers may not devote sufficient resources to collaborations or may otherwise fail in the aspects of the collaboration for which they are responsible. Disagreements over the implementation and management of the program may occur, which could lead to material delays and/or a failure to achieve the successful development of technology through the CDP. If we fail to achieve successful collaborations, or if our customers are dissatisfied with the results of or the way we design and manage a CDP, our operating results and financial condition would be materially and adversely affected.

Our strategy includes conducting proprietary R&D efforts in collaboration with and on behalf of multiple customers. Failure to adequately protect against potential conflicts of interest and breaches of confidentiality would harm our reputation and our relationships with our customers, and our business prospects and operating results would be adversely affected. Moreover, some potential customers may hesitate to grant us access to their proprietary information, which could impair our ability to provide value for such customers.

        Our strategy includes conducting proprietary R&D efforts in collaboration with and on behalf of customers who in some cases may have overlapping interests and technologies. We seek to structure our collaborative agreements and business practices to minimize any potential conflicts and the possibility of any breaches of confidentiality. We may need access to some of our customers' proprietary information, and they may be reluctant to share it with us because of the risk of a potential conflict between us and/or our customers and other potential customers and the risk of a breach of confidentiality. Our failure to do so could result in our inability to attract new customers or retain existing customers, or lead to our having incomplete information with respect to existing customers that could impair our ability to fully address the customers' needs and demonstrate the value of our technology to the customers. Even if we make significant efforts to isolate each development activity, we may fail to meet the contractual confidentiality commitments as to one or more customers. Moreover, even if we meet these commitments, conflicts between a customer and us, or between or among customers, could nevertheless arise. In either event, we may become involved in a dispute with our customers regarding the solutions developed during the collaboration or the rights to these solutions, including possible litigation. Disputes of this nature could harm the relationship between us and our customers, and could adversely affect our ability to enter into new CDPs and cause our revenue and operating results to decline.

We may be unable to make the substantial R&D investments required to remain competitive in our business.

        The semiconductor and clean-energy industries require substantial investment in R&D to develop and bring to market new and enhanced technologies and products. To remain competitive, we anticipate that we will need to maintain or increase our levels of R&D expenditures to keep pace with the development efforts of our customers. We expect R&D expenses to increase in absolute dollars for the foreseeable future, due to the increasing complexity and number of solutions we plan to develop both for our customers and internally, the expansion of our customer base and any associated increase in upfront R&D costs. In addition, the ultimate success of products incorporating our technology will depend in part on significant continued investment in R&D by our customers. We do not know whether we or our customers will have sufficient resources to maintain or increase the level of investment in R&D required to remain competitive. In addition, we cannot assure you that the technologies, products and applications on which we and our customers have focused our R&D expenditures will become commercially successful. If we are required to invest significantly greater

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resources than anticipated in our R&D efforts without a corresponding increase in revenue, our operating results could be materially and adversely affected.

If we are unable to develop our platform and expertise to support our future growth plans, our business and operating results could be adversely affected.

        We intend to further develop and broaden our HPC platform, including our software and informatics capabilities, to address a wider range of markets and customers for multiple applications within semiconductors, flat glass, solar cells, light emitting diodes (LEDs), flat-panel displays, advanced batteries and other energy-efficient technologies. However, we have limited expertise and experience in certain of these fields, and if we are unable to develop our platform and expertise to support these fields our business growth might be limited, and our business and operating results could be adversely affected.

If we lose one or more of our key personnel without obtaining adequate replacements in a timely manner or if we are unable to retain and recruit skilled personnel, our operations could become disrupted and the growth of our business could be delayed or restricted.

        Our success depends, in large part, on the continued contributions of our senior management team, in particular, the services of Mr. David Lazovsky, our President and Chief Executive Officer, and Dr. Tony Chiang, our Chief Technology Officer. If we lose the services of Mr. Lazovsky or Dr. Chiang, it could slow the execution of our business plan, hinder our development processes and impair our sales efforts, and searching for a replacement could divert our other senior management's time and increase our operating expenses. In addition, our customers could become concerned about our future operations, which could harm our reputation.

        None of our senior management is bound by written employment contracts to remain with us for a specified period. The loss of any of our senior management could harm our ability to implement our business strategy and respond to the rapidly changing market conditions in which we operate. Upon hiring or promotion, new senior management personnel must spend a significant amount of time learning our technology, business model and management systems and their new roles, in addition to performing their regular duties. Accordingly, until new senior personnel become familiar with our technology, business model and systems or with their new roles, we may experience some disruption to our ongoing operations. Moreover, the loss of a member of our senior management or our professional staff would require the remaining management to divert attention to seeking a replacement.

        Our future success and competitiveness depends on our ability to retain and motivate our unique team of highly skilled scientists and engineers, who have expertise across various disciplines, fields and technologies, including engineering, materials science, process development and integration, equipment, device process technologies and device integration. In addition, as we grow, we will have to continue to retain, attract and motivate qualified and talented personnel, including our scientists and engineers, management, sales and marketing and legal and finance personnel. Because our CDPs are customer-specific and project-specific and last for a significant period of time, the loss of key scientists or engineers or other personnel could have an adverse effect on a particular development program and on our ability to deliver results to a customer in a timely manner or at all. We do not know whether we will be able to retain all of these employees as we continue to pursue our business strategy. Competition for personnel is intense in the semiconductor and clean-energy industries.

        We may encounter difficulties in hiring qualified scientists and engineers because there is a limited pool of scientists and engineers with the specialized expertise required to understand and implement our platform in conjunction with our customers. Further, we may have difficulty in obtaining visas permitting entry for some of our employees who are foreign nationals into the United States, and delays in obtaining visas permitting entry into other key countries for several of our key personnel,

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which could disrupt our ability to strategically locate our personnel. The loss of the services of key employees or our inability to retain, attract and motivate qualified scientists and engineers could have a material adverse effect on our business, financial condition and results of operations.

Following the completion of this offering, we may have a financial obligation to Symyx Technologies, Inc.

        In connection with an agreement for the purchase of intellectual property and the termination of our royalty obligations under an existing license agreement, we have an obligation to issue a promissory note to Symyx Technologies, Inc. (Symyx), a wholly-owned subsidiary of Accelrys, Inc., upon the consummation of this offering to the extent the gross proceeds from Symyx's sale of                        shares in this offering (before deducting underwriting discounts and commissions and estimated offering expenses) are less than $67 million. At an assumed initial public offering price of $        per share (the midpoint of the price range set forth on the cover page of this prospectus) the gross proceeds from the sale of Symyx's shares would be $             million, and we would have a $            obligation to Symyx. A $1.00 increase (decrease) in the assumed initial public offering price of $        per share would increase (decrease) the gross proceeds to Symyx by $             million. Such note, if issued, would have a term of 24 months and an interest rate equal to 4%. Such note would be payable in an amount equal to the lesser of the principal amount and the greater of $500,000 per quarter or the amount of accrued interest, with a balloon payment at maturity if applicable. Such note would also be pre-payable by us at any time without penalty or premium, and would be secured by tangible personal property, excluding intellectual property. If we issue such note, a portion of the net proceeds of this offering received by us would be used to make payments of scheduled interest and payment of principal at any time at or prior to maturity. Such financial obligation would limit our ability to use the net proceeds of this offering for other purposes.

We may be unable to effectively protect our intellectual property, which would negatively affect our ability to compete.

        We depend on our proprietary HPC platform for our success and ability to compete. If others are able to reproduce our technology, our business will suffer significantly unless we can prevent them from competing with us. As of September 1, 2011, we owned 106 U.S. patents and patent applications (most of which also have foreign counterparts), which we believe protect our rights in our HPC platform, and we continue to file patent applications to seek protection for the further evolution of our HPC platform. Patent laws provide only limited protection, however. We cannot assure you that all maintenance fees have been paid or that all filings have been made with the appropriate regulatory or governmental authorities with respect to any IP registered or applied for outside of the U.S. that we purchase. Also, patent protection in foreign countries may be limited or unavailable where we need this type of protection. A more detailed description of how we protect our IP is set forth in the section entitled "Business—Intellectual Property."

        The patent positions of technology companies, including ours, are often uncertain and involve complex legal and factual questions. We will be able to protect our proprietary rights from unauthorized use by third parties only to the extent that our proprietary technologies are covered by valid and enforceable patents or are effectively maintained as trade secrets. We apply for patents covering our HPC platform and further advancements of our HPC platform as we deem appropriate. However, we may not obtain patents on all inventions for which we seek patents, and any patents we obtain may be challenged (both before and after any such patents issue) and may be narrowed in scope or extinguished as a result of these challenges. Additional uncertainty may result from potential passage of patent reform legislation by the United States Congress, legal precedent as handed down by the United States Federal Circuit and Supreme Court as they determine legal issues concerning the scope and construction of patent claims and inconsistent interpretation of patent laws by the lower courts. For these reasons, among others, our existing patents and any future patents we obtain may not be sufficiently broad to prevent others from practicing our technologies or from developing similar or superior products. In that case, our revenue and operating results could decline.

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        Our strategy includes obtaining patent protection for technology developed in collaboration with our customers. A portion of our revenue from our customers derives from the licenses granted to our customers under these patents. If we are unable to obtain this type of protection, we would not be able to enforce exclusive rights to the technologies in question, and our revenue and operating results could decline.

        We have in the past, and may in the future, develop patented technology with U.S. federal government funding. When new technologies are developed with U.S. government funding, the government obtains certain rights in any resulting patents, including a nonexclusive license authorizing the government to use the invention for non-commercial purposes. These rights may permit the government to disclose our confidential information to third parties and to exercise "march-in" rights to use or allow third parties to use our patented technology. The government can exercise its march-in rights if it determines that action is necessary because we fail to achieve practical application of the U.S. government-funded technology, because action is necessary to alleviate health or safety needs, to meet requirements of federal regulations, or to give preference to U.S. industry. In addition, U.S. government-funded technology may be subject to restrictions on transfer to foreign entities, and some U.S. government-funded data may be subject to public disclosure under the Freedom of Information Act.

        Many of our customers and competitors have significant operations outside the United States. Foreign laws may not afford us sufficient protections for our intellectual property, however, and we may not always seek patent protection outside the United States. We believe that our success depends, in part, upon our ability to obtain international protection for our IP. However, the laws of some foreign countries may not be as comprehensive as those of the United States and may not be sufficient to protect our proprietary rights abroad. Accordingly, our international competitors could obtain foreign patent protection for, and market overseas, products and technologies for which we are seeking patent protection in the United States.

Confidentiality agreements with employees and others may not adequately prevent disclosures of trade secrets and other proprietary information.

        We rely in part on trade secret protection to protect our confidential and proprietary information and processes. However, trade secrets are difficult to protect. We have taken measures to protect our trade secrets and proprietary information, but these measures may not be effective. We require new employees and consultants to execute confidentiality agreements upon the commencement of an employment or consulting arrangement with us. These agreements generally require that all confidential information developed by the individual or made known to the individual by us during the course of the individual's relationship with us be kept confidential and not disclosed to third parties. These agreements also generally provide that inventions conceived by the individual in the course of rendering services to us shall be our exclusive property. Nevertheless, employees, collaborators or consultants may still disclose or misuse our confidential information, and we may not be able to meaningfully protect our trade secrets. In addition, others may independently develop substantially equivalent information or techniques or otherwise lawfully gain access to our trade secrets, and thereafter communicate this information to others without maintaining its confidentiality. Costly and time-consuming litigation could be necessary to enforce and determine the scope of our proprietary rights, and failure to obtain or maintain trade secret protection could adversely affect our competitive business position.

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Significant litigation over intellectual property in the industry may cause us to become involved in costly and lengthy litigation, which could subject us to liability, require us to stop licensing our developed technology or force us to develop new technology.

        Whether or not patents are granted to us, litigation may be necessary to enforce our IP rights, to defend against a claim of infringement of IP rights of others or to determine the validity and scope of the proprietary rights of others. Because infringement is a fact-intensive inquiry, and because patent applications in the United States and many foreign jurisdictions are typically not published until eighteen months after filing (or, in some cases, are not published until they issue as patents), we cannot be certain that we do not now, and will not in the future, infringe a third party's patent rights. We may also become party to claims by our customers to IP rights developed by us in connection with a CDP. If our customers become involved in disputes with third parties over allegations that our customers' practice of our IP rights infringes the IP rights of such third parties, it may also become necessary for us to become involved in such disputes.

        Any claim, even if without merit, could be time consuming to defend, result in costly litigation, or require us to enter into licensing agreements, resulting in unexpected operating costs. Moreover, our opponents in any litigation may have significantly more resources with which to defend against or assert claims in the litigation. A successful claim of infringement against us in connection with the use of our technologies could force us to stop using our technologies that incorporate the infringed IP; pay substantial monetary damages or royalties; grant cross-licenses to third parties relating to our own IP; obtain a license from the owner of the infringed IP, which may not be available to us on acceptable terms or at all; or re-engineer our platform or products to avoid further IP infringement, which may be technically impossible or commercially infeasible. The occurrence of any of these eventualities could adversely affect our business Even if we are successful in defending such a claim, litigation could also divert our resources, including our managerial and engineering resources. Any infringement claim or other litigation against or by us could have a material negative effect on our business.

Our intellectual property indemnification policies and obligations may adversely impact our business and operating results.

        Any assertion by a third party asserting ownership or other rights to technology developed through our CDPs could result in our customers becoming the target of litigation and we may be bound to indemnify our customers under the terms of our license agreements. These obligations could result in substantial expenses to us, which could have a material adverse effect on our business, financial condition and results of operations. In addition to the time and expense required for us to satisfy our support and indemnification obligations to our customers, any litigation could severely disrupt or shut down the business of our customers, which in turn could damage our relations with them and have a material adverse effect on our reputation, business, financial condition and results of operations.

We will need to rely on our customers to deliver timely and accurate information to accurately report our financial results from licensing and royalty revenue in the time frame and manner required by law.

        We will need to receive timely, accurate and complete information from our customers to accurately report our financial results on a timely basis. Licensing and royalty revenue we may receive in the future may be based on the revenue from the sale of our customers' products that incorporate technology developed through our CDPs, and we will need to rely on our customers to provide us with complete and accurate information regarding revenue and payments owed to us on a timely basis. If the information that we receive is not accurate, we may not receive the full amount of revenue that we are entitled to under these arrangements on a timely basis, which could result in adjustments to our financial results in a future period. Although we typically have audit rights with these parties, performing this type of audit could be harmful to our collaborative relationships, expensive and

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time-consuming and may not be sufficient to reveal any discrepancies in a timeframe consistent with our reporting requirements.

We may need additional capital in the future to finance our business.

        Our future capital requirements may be substantial, particularly as we continue to develop our business and expand our collaborative development efforts. Although we believe that, based on our current level of operations and anticipated growth, our existing cash, cash equivalents and marketable securities, combined with the net proceeds from this offering, will provide adequate funds for ongoing operations, planned capital expenditures and working capital requirements for at least the next 12 months, we may need additional capital if our current plans and assumptions change. Our need for additional capital will depend on many factors, including the financial success of our business, whether we are successful in obtaining payments from customers, whether we can enter into additional collaborations, the progress and scope of collaborative R&D projects performed by us and our customers, the effect of any acquisitions of other businesses or technologies that we may make in the future, the filing, prosecution and enforcement of patent claims, how quickly we expand, how much we need to develop or enhance our solutions or HPC platform and any necessary responses to competitive pressures.

        If our capital resources are insufficient to meet our capital requirements, and our revenue is insufficient to support any of these activities, then we will have to raise additional funds. If future financings involve the issuance of equity securities, our then-existing stockholders would suffer dilution. If we raised additional debt financing, we may be subject to restrictive covenants that limit our ability to conduct our business. We may not be able to raise sufficient additional funds on terms that are favorable to us, if at all. If we fail to raise sufficient funds and continue to incur losses, our ability to fund our operations, take advantage of strategic opportunities, develop products or technologies or otherwise respond to competitive pressures could be significantly limited. If this happens, we may be forced to delay or terminate R&D programs, curtail or cease operations, obtain funds through collaborative and licensing arrangements that may require us to relinquish commercial rights, or grant licenses on terms that are not favorable to us. If adequate funds are not available, we may not be able to successfully execute our business plan or continue our business.

Failure of suppliers to timely deliver sufficient quantities of the components, materials or software used in our collaborations, may result in delays or other disruptions in executing our CDPs, which could adversely affect our business and operating results.

        We have historically relied on a small number of contract manufacturing companies for the manufacture and assembly of a majority of our HPC tools. While we are not dependent on any single contract manufacturing company, key parts of our tools are currently available only from a limited number of sources. In addition, components of our capital equipment are available from only a few suppliers. If supplies from these vendors are delayed or interrupted for any reason, we may not be able to get equipment or components for our tools or our own research efforts in a timely fashion or in sufficient quantities or under acceptable terms, if at all. Even though alternative sources of supply would be available, it could be time-consuming and expensive for us to qualify new vendors and work with them to integrate our designs into the tools they manufacture for us. In addition, we depend upon our vendors to provide components of appropriate quality and reliability. Consequently, if supplies from these vendors were delayed or interrupted for any reason, it could materially and adversely affect our business.

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Our business strategy requires us to evaluate, integrate and develop elements of our customers' value chains, including development and manufacturing processes. Our ability to evaluate these effectively may sometimes depend on the cooperation from our customers' materials suppliers and equipment manufacturers as well as access to their data and tools. If these third parties do not cooperate with us or provide us access to the necessary materials, tools or equipment we may not be able to deliver effective solutions to our customers, which would adversely affect our business and results of operations.

        We have to evaluate multiple elements of our customers' value chains to help them test and develop end products that meet their specifications, including the materials, tools and equipment used by them during the manufacturing process. Our ability to evaluate a customer's value chain effectively may sometimes depend on cooperation from such customer's materials suppliers and equipment manufacturers and on access to their data and tools. Our evaluation of the materials and equipment in the value chain must be unbiased to maintain credibility with our customers, and our evaluation sometimes results in recommendations that our customers change materials, tools or equipment. Our recommendations may negatively impact our relationships with materials and tool providers and equipment manufacturers. Tensions in our relationships with these providers and manufacturers may cause these parties to limit or deny our access to their newest materials and equipment, which would in turn limit our ability to complete our development activities with our customers or control the quality of the combinatorial methods applied to their development efforts, which would adversely affect our business and operations.

If we cannot compete successfully in our industry, our results of operations and financial condition would be adversely affected.

        Competition in our market may intensify in the future, which could slow our ability to grow or execute our strategy and could lead to increased pricing pressure, negatively impacting our revenue. Our current and potential customers may choose to develop their own combinatorial development methods internally, particularly if we are slow in deploying our solutions or improving them to meet market needs. We currently face indirect competition from the internal R&D groups at integrated circuit (IC) companies, particularly those of our customers who work with us to develop knowledge of combinatorial methods and who may then use our methods independently. Our customers do not license our technology exclusively, and several of them also design, develop, manufacture and market semiconductor projects based on their own or other architectures and develop their own intellectual property internally. They often compete with each other and with us in various applications. Our customers are generally much larger and have significantly greater resources than us. We also face indirect competition from university collaborations, consortia and alliance partnerships. In addition, there may be other providers of high-throughput empirical solutions for the design of and R&D relating to integrated devices of which we are not aware and there may be new entrants to the industry in the future, particularly if acceptance of these solutions grows. In addition, we believe that the demand for solutions that address the need for better integration between the design and manufacturing processes may encourage direct competitors to enter into our market. Other potential competitors include fabrication facilities that may decide to offer solutions competitive with ours as part of their value proposition to their customers. If these potential competitors change the pricing environment or are able to attract industry partners or customers faster than we can, we may not be able to grow and execute our strategy as quickly or at all.

The semiconductor industry is highly cyclical, subject to price volatility, difficult to predict and subject to significant downturns.

        Currently, the substantial majority of our revenue is dependent upon the overall condition of the semiconductor industry, especially in light of the licensing component of our revenue. The semiconductor industry is highly cyclical and subject to rapid technological change and has been subject

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to significant economic downturns at various times, such as the recent economic downturn, characterized by diminished product demand, accelerated erosion of average selling prices and production overcapacity. The semiconductor industry also periodically experiences increased demand and production capacity constraints. In addition, the semiconductor industry has historically experienced price volatility. As a result, we may experience significant fluctuations in operating results due to general semiconductor industry conditions and overall economic conditions.

        In 2008 and 2009, the semiconductor industry experienced significant challenges as a result of the severe tightening of the credit markets, turmoil in the financial markets, and weakened global economy. While the semiconductor market recovered somewhat in 2010 and the first part of 2011, the recovery may not continue, which limits our ability to forecast our business. There may be sudden changes in our customers' manufacturing capacity requirements and spending, which depend in part on capacity utilization, demand for our customers' IC products by consumers, inventory levels relative to demand, and access to affordable capital. In addition, the semiconductor industry has experienced significant consolidation in the past and may continue to see high levels of consolidation in the future. If any of our customers are acquired, the acquiror may not continue to engage in a CDP with us. Alternatively, our customers may opt to acquire companies or technologies that decrease their need for our services or otherwise divert their R&D resources. As a result of these and other potential changes, the timing and length of any cycles can be difficult to predict. Further, uncertainty about future global economic conditions and any effect on the semiconductor industry could make it challenging for us to forecast our operating results, make business decisions and identify the risks that may affect our business, financial condition and results of operations. If we are not able to timely and appropriately adapt to changes resulting from the difficult macroeconomic environment, our business, financial condition and results of operations may be significantly negatively affected.

A substantial portion of our revenue is derived from business arrangements with related parties, and such arrangements could create conflicts of interest that could adversely affect our business and results of operations.

        Some of our customers and other business partners hold a significant stake in our capital stock. Related party transactions disclosed in our financial statements accounted for $10.4 million and $26.0 million, or 43.5% and 61.0%, respectively, of our revenue for the six months ended June 30, 2011 and the year ended December 31, 2010. ATMI, which beneficially owns approximately 10.6% of our capital stock as of September 1, 2011, accounted for $7.8 million and $22.1 million, or 32.7% and 51.8%, respectively, of our revenue for the six months ended June 30, 2011 and the year ended December 31, 2010. For more information about these transactions, see "Certain Relationships and Related Party Transactions" and Note 11 to our consolidated financial statements. We have also entered into CDPs with GLOBALFOUNDRIES, whose majority stockholder, Advanced Technology Investment Company, LLC, beneficially owns approximately 4.4% of our capital stock (assuming exercise of an outstanding warrant held by them) as of September 1, 2011, and SanDisk Corporation and Toshiba Corporation, which collectively hold warrants exercisable for an aggregate of 1,644,736 shares of our common stock.

        We believe that the transactions and agreements that we have entered into with related parties are on terms that are at least as favorable as could reasonably have been obtained at such time from third parties. However, these relationships could create, or appear to create, potential conflicts of interest when our board of directors is faced with decisions that could have different implications for us and our related parties or their affiliates. In addition, conflicts of interest may arise between us and our related parties and their affiliates. The appearance of conflicts, even if such conflicts do not materialize, might adversely affect the public's perception of us, as well as our relationship with other companies and our ability to enter into new relationships in the future, including new CDPs with competitors of such related parties, which could have a material adverse effect on our ability to do business.

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We are subject to warranty claims, product recalls and product liability.

        We may, from time to time, be subject to warranty or product liability claims for our HPC tools that may in the future lead to expenses as we compensate affected customers for costs incurred related to product quality issues. Although we maintain product liability insurance, such insurance is subject to significant deductibles and there is no guarantee that such insurance will be available or adequate to protect against all such claims. Alternatively, we may elect to self-insure with respect to certain matters. We may incur costs and expenses in the event of any recall of a HPC tool sold to our customers. We may incur replacement costs, contract damage claims from our customers and reputational harm. Costs or payments made in connection with warranty and product liability claims and product recalls could materially affect our financial condition and results of operations.

Compliance with environmental, health and safety laws and regulations could increase costs or cause us to incur substantial liabilities.

        We are subject to various foreign, federal, state and local environmental laws and regulations governing, among other matters, emissions and discharges of hazardous materials into the air and water, the use, generation, storage, handling, transportation and disposal of, and exposure to, hazardous materials and wastes, remediation of contamination and employee health and safety. In addition, under certain of these environmental laws, liability can be joint and several and without regard to comparative fault. Our operations involve the use of hazardous materials and produce hazardous waste, and we could become liable for any injury or contamination that could arise due to such use or disposal of these materials. Failure to comply with environmental laws and regulations could result in the imposition of substantial civil and criminal fines and sanctions, could require operational changes or limits or the installation of costly equipment or otherwise lead to third party claims. Future environmental laws and regulations, stricter enforcement of existing laws and regulations, or the discovery of previously unknown contamination or violations of such laws and regulations could require us to incur costs or become the basis for new or increased liabilities, which could impair our operations and adversely affect our business and results of operations.

Acquisitions may harm our business and operating results, cause us to incur debt or assume contingent liabilities or dilute our shareholders.

        We have made and may in the future make strategic investments or acquisitions where there is an opportunity to expand the potential applications and reach of our HPC platform. Exploring and implementing any investments or acquisitions may place strain upon our ability to manage our future growth and may divert management attention from our core development and licensing business. There are also other risks associated with this strategy. We cannot assure you that we will be able to make investments or acquire businesses on satisfactory terms, that any business acquired by us or in which we invest will be integrated successfully into our operations or be able to operate profitably, or that we will be able to realize any expected synergies or benefits from such investments or acquisitions. Our relative inexperience in effecting such transactions heightens these risks. In addition, to finance any acquisitions or investments, we may utilize our existing funds, or might need to raise additional funds through public or private equity or debt financings. Prolonged tightening of the financial markets may impact our ability to obtain financing to fund future acquisitions and we could be forced to obtain financing on less than favorable terms. Additionally, equity financings may result in dilution to our stockholders. We cannot predict the number, timing or size of investments or acquisitions, or the effect that any such transactions might have on our operating results.

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Global or regional economic, political and social conditions could adversely affect our business and operating results.

        We operate in multiple jurisdictions throughout the world and are subject to foreign business, political and economic risks. In particular, we are subject to risks arising from adverse changes in global economic conditions. Global economic uncertainties in the key markets of many of our customers may cause our customers to delay or reduce technology purchases and investments. The impact of this on us is difficult to predict, but if businesses defer licensing our technology, require fewer CDPs or development tools, or if consumers defer purchases of new products that incorporate technology developed through our CDPs, our revenue could decline. A decline in revenue would have an adverse effect on our results of operations and our financial condition.

        In addition, some of our largest customers are located outside of the United States, primarily in Asia, which further exposes us to foreign risks. Also, a substantial portion of the consumer products market that serves as the end-market for the products we help our customers to develop is located in Asia. As a result, our operations are subject to substantial influence by political and economic conditions in Asia, as well as natural disasters such as the recent earthquake and tsunami and related nuclear power plant crisis in Japan. Reduced end user demand as well as disruptions to the supply chain for our customers resulting from these events could lead to a reduction in our revenue and an adverse impact on our financial condition.

        We are also subject to general geopolitical risks in connection with international operations, such as political, social and economic instability, terrorism, interference with information or communication of networks or systems, potential hostilities, changes in diplomatic and trade relationships, and disease outbreaks, and any disruptive effect these events would have on our business operations. Although to date we have not experienced any material adverse effect on our operations as a result of these types of regulatory, geopolitical, and other factors, we cannot assure investors that these factors will not have a material adverse effect on our business, financial condition, and operating results or require us to modify our current business practices. Inconsistencies among, and unexpected changes in, a wide variety of foreign laws and regulatory environments with which we are not familiar, including, among other issues, with respect to employees, protection of our intellectual property, and a wide variety of operational regulations and trade and export controls under domestic, foreign, and international law may also have unexpected, adverse impacts on our operations and financial condition.

In the future, exchange rate fluctuations could affect our revenue, which could adversely affect our business and operating results.

        Our licensing and royalty revenue is derived from sales of our customers' products that incorporate technology developed through our CDPs. To the extent that sales for these customer products are denominated in a foreign currency, an increase in the value of the U.S. dollar relative to such foreign currencies could adversely affect our licensing and royalty revenue irrespective of the volume of such products sold, which could adversely affect our business and operating results.

        In addition, we derive a significant portion of our revenue from customers in foreign countries, particularly those based in Japan. Revenue generated from customers in Japan accounted for 29%, 30% and 27% of total revenue for the years ended December 31, 2010, 2009 and 2008, respectively. We expect that a significant portion of our total future revenue will continue to be derived from companies based in Japan and other foreign countries. If the U.S. dollar increases in value relative to the currencies in any of these countries, the cost of our CDPs, which have historically been billed in U.S. dollars, will be more expensive to existing and potential customers in those countries, which could adversely affect our ability to generate new or expand existing CDPs.

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Business interruptions could delay us in the process of developing our products and could disrupt our sales.

        Our headquarters are located in the San Francisco Bay Area near known earthquake fault zones and are vulnerable to significant damage from earthquakes. We are also vulnerable to other types of natural disasters and other events that could disrupt our operations, such as terrorist acts and other events beyond our control. We do not carry insurance for earthquakes and we may not carry sufficient business interruption insurance to compensate us for losses that may occur. Any losses or damages we incur could have a material adverse effect on our cash flows and success as an overall business.

Our ability to use our net operating loss carryforwards to offset future taxable income, and our ability to use our tax credit carryforwards, may be subject to certain limitations.

        In general, a corporation that undergoes an "ownership change" under Section 382 of the Internal Revenue Code is subject to limitations on its ability to utilize its pre-change net operating loss carryforwards (NOLs) to offset future taxable income and its ability to utilize tax credit carryforwards. As of December 31, 2010, we reported U.S. federal NOLs of approximately $17.4 million. In general, an "ownership change" occurs if the aggregate stock ownership of certain stockholders (generally, 5% shareholders, applying certain aggregation and look-through rules) increases by more than 50 percentage points over such stockholders' lowest percentage ownership during the testing period (generally, three years). We have not determined whether an ownership change has occurred in the past. If we have experienced an ownership change in the past, or if we undergo an ownership change in connection with this offering, our ability to utilize NOLs and tax credit carryforwards could be limited. Furthermore, future changes in our stock ownership, such as certain stock issuances and transfers between stockholders, some of which changes are outside of our control, could result in ownership changes under Section 382 of the Internal Revenue Code. For these reasons, we may not be able to utilize a material portion of our NOLs and tax credit carryforwards, even if we attain profitability.

Risks Relating to this Offering and Ownership of Our Common Stock

An active trading market for our common stock may not develop, and you may not be able to resell your shares at or above the initial public offering price.

        Prior to this offering, there has been no public market for shares of our common stock. Although we will apply to have our common stock approved for quotation on a stock exchange, an active trading market for our shares may never develop or be sustained following this offering. The initial public offering price of our common stock will be determined through negotiations between us and the underwriters. This initial public offering price may not be indicative of the market price of our common stock after this offering. In the absence of an active trading market for our common stock, investors may not be able to sell their common stock at or above the initial public offering price or at the time that they would like to sell.

Our stock price may be volatile, and the market price of our common stock after this offering may drop below the price you pay.

        The market price of our common stock could be subject to significant fluctuations after this offering and it may decline below the initial public offering price. Market prices for securities of early stage companies have historically been particularly volatile. As a result of this volatility, you may not be able to sell your common stock at or above the initial public offering price. These fluctuations could be in response to, among other things, the factors described in this "Risk Factors" section or elsewhere in this registration statement, or other factors, some of which are beyond our control, such as:

•

fluctuations in our financial results or outlook or those of companies perceived to be similar to us;

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•

changes in estimates of our financial results or recommendations by securities analysts;



•

changes in market valuations of similar companies;



•

changes in our capital structure, such as future issuances of securities or the incurrence of debt;



•

announcements by us or our competitors of significant contracts, acquisitions or strategic alliances;



•

litigation involving us, our general industry or both;



•

additions or departures of key personnel;



•

regulatory developments in the U.S., countries in Asia, and/or other foreign countries;



•

investors' general perception of us; and



•

changes in general economic, industry and market conditions.

        Furthermore, the stock markets have experienced price and volume fluctuations that have affected, and continue to affect, the market prices of equity securities of many companies. These fluctuations often have been unrelated or disproportionate to the operating performance of those companies. These broad market fluctuations, as well as general economic, political and market conditions, such as recessions, interest rate changes and international currency fluctuations, may negatively affect the market price of our common stock.

        In the past, many companies that have experienced volatility in the market price of their stock have become subject to securities class action litigation. We may be the target of this type of litigation in the future. Securities litigation against us could result in substantial costs and divert our management's attention from other business concerns, which could seriously harm our business.

We will incur increased costs and demands upon management as a result of complying with the laws and regulations affecting public companies, which could harm our results of operations.

        As a public company, we will incur significant additional accounting, legal and other expenses that we did not incur as a private company, including costs associated with public company reporting requirements. We have incurred and will continue to incur costs associated with corporate governance requirements, including requirements under Section 404 and other provisions of the Sarbanes-Oxley Act, as well as rules implemented by the Securities Exchange Commission, or SEC, and the exchange on which we list our common stock. The expenses incurred by public companies for reporting and corporate governance purposes have increased dramatically in recent years. We expect these rules and regulations to substantially increase our financial and legal compliance costs. In addition, these rules and regulations are subject to change from time to time, and we may incur additional financial and legal compliance costs as we seek to understand and comply with changes in these rules and regulations. We also expect that as we become a public company it will be more difficult and more expensive for us to obtain director and officer liability insurance, and we may be required to accept reduced policy limits and coverage or incur substantially higher costs to obtain the same or similar coverage previously available. As a result, it may be more difficult for us to attract and retain qualified individuals to serve on our board of directors or as our executive officers.

If we experience material weaknesses or otherwise fail to maintain an effective system of internal controls in the future, we may not be able to accurately report our financial condition or results of operations, which may adversely affect investor confidence in our company and, as a result, the value of our common stock.

        As a result of becoming a public company, we will be required, under Section 404 of the Sarbanes-Oxley Act, to furnish a report by management on, among other things, the effectiveness of our internal control over financial reporting for the first fiscal year beginning after the effective date of this

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offering. This assessment will need to include disclosure of any material weaknesses identified by our management in our internal control over financial reporting, as well as an opinion from our independent registered public accounting firm on the effectiveness of our internal control over financial reporting. A material weakness is a control deficiency or combination of control deficiencies that results in more than a remote likelihood that a material misstatement of annual or interim financial statements will not be prevented or detected.

        We are in the very early stages of the costly and challenging process of hiring personnel and compiling the system and processing documentation necessary to perform the evaluation needed to comply with Section 404. We may not be able to complete our evaluation, testing and any required remediation in a timely fashion. During the evaluation and testing process, if we identify one or more material weaknesses in our internal control over financial reporting, we will be unable to assert that our internal controls are effective. We cannot assure you that there will not be material weaknesses and significant deficiencies in our internal controls in the future. If we are unable to conclude that our internal control over financial reporting is effective, or if our independent registered public accounting firm were to issue an adverse opinion on the effectiveness of our internal control over financial reporting, we could lose investor confidence in the accuracy and completeness of our financial reports, which would cause the price of our common stock to decline.

        We have not completed a testing cycle under Section 404 of the Sarbanes-Oxley Act and cannot assure you that we will be able to implement and maintain an effective internal control over financial reporting in the future. Any failure to maintain such controls could severely inhibit our ability to accurately report our financial condition or results of operations.

The concentration of our capital stock ownership with insiders upon the completion of this offering will limit your ability to influence corporate matters.

        We anticipate that our executive officers, directors, current five percent or greater stockholders and entities affiliated with them will together beneficially own approximately        % of our common stock outstanding after this offering. Entities affiliated with Redpoint Ventures, entities affiliated with CMEA Ventures and entities affiliated with U.S. Venture Partners will beneficially own approximately      %,      % and      % of our common stock outstanding after this offering. This significant concentration of share ownership may adversely affect the trading price for our common stock because investors often perceive disadvantages in owning stock in companies with concentrated stock ownership. Also, these stockholders, acting together, will be able to influence our management and affairs and matters requiring stockholder approval, including the election of directors and the approval of significant corporate transactions, such as mergers, consolidations or the sale of substantially all of our assets. Consequently, this concentration of ownership may have the effect of delaying or preventing a change of control, including a merger, consolidation or other business combination involving us, or discouraging a potential acquirer from making a tender offer or otherwise attempting to obtain control, even if that change of control would benefit our other stockholders.

A significant portion of our total outstanding shares may be sold into the public market in the near future, which could cause the market price of our common stock to drop significantly, even if our business is doing well.

        Sales of a substantial number of shares of our common stock in the public market could occur at any time after the expiration of the lock-up agreements described in the "Underwriting" and "Shares Eligible for Future Sale—Lock-up Agreements" sections of this prospectus. These sales, or the market perception that the holders of a large number of shares intend to sell shares, could reduce the market price of our common stock. After this offering, we will have          shares of common stock outstanding based on the number of shares outstanding as of June 30, 2011 and assuming the conversion of all shares of preferred stock into shares of our common stock and no exercise of outstanding options or

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warrants after June 30, 2011. This includes the          shares that we are selling in this offering, which may be resold in the public market immediately after this offering. The remaining                        shares, or      % of our outstanding shares after this offering, are currently restricted as a result of securities laws or lock-up agreements but will be able to be sold, subject to any applicable volume limitations under federal securities laws, in the near future as set forth below:

•

shares will be eligible for sale immediately upon completion of this offering; and



•

shares will be eligible for sale upon the expiration of 180-day lock-up and/or market standoff agreements, subject in some cases to the volume and other restrictions of Rule 144 and Rule 701 promulgated under the Securities Act of 1933, as amended, or the Securities Act, and upon the lapse of our right of repurchase with respect to any unvested shares.

        The lock-up agreements expire 180 days after the date of this prospectus, except that the 180-day period may be extended in certain cases for up to 34 additional days under certain circumstances where we announce or pre-announce earnings or a material event occurs within approximately 17 days prior to, or approximately 16 days after, the termination of the 180-day period. The representatives of the underwriters may, in their sole discretion and at any time without notice, release all or any portion of the securities subject to lock-up agreements.

        Following this offering, holders of              shares of our common stock (including shares issuable upon exercise of certain stock options) not sold in this offering will be entitled to rights with respect to the registration of these shares under the Securities Act. See "Description of Capital Stock—Registration Rights." If we register their shares of common stock following the expiration of the lock-up agreements, these stockholders could sell those shares in the public market without being subject to the volume and other restrictions of Rule 144 and Rule 701.

        After the closing of this offering, we intend to register approximately              shares of common stock that have been reserved for issuance under our stock incentive plans. Of these shares, approximately              shares will be eligible for sale upon the exercise of outstanding options after the expiration of the lock-up agreements.

Purchasers in this offering will experience immediate and substantial dilution in the book value of their investment.

        The initial public offering price of our common stock is substantially higher than the net tangible book value per share of our outstanding common stock immediately after this offering. Therefore, if you purchase our common stock in this offering, you will incur immediate dilution of approximately $      in net tangible book value per share from the price you paid, based on an assumed initial offering price of $      per share, the midpoint of the range set forth on the cover of this prospectus. In addition, investors purchasing common stock in this offering will own only approximately      % of our shares outstanding after this offering even though they will have contributed       % of the total consideration received by us in connection with our sales of common stock. Moreover, we issued options and warrants in the past to acquire our stock at prices significantly below the initial public offering price. As of June 30, 2011, 16,403,610 shares of common stock were issuable upon exercise of outstanding stock options with a weighted average exercise price of $1.09 per share. As of June 30, 2011, warrants to purchase 4,446,721 shares of common stock (assuming conversion of all shares of preferred stock into common stock as of June 30, 2011) were issuable upon exercise of outstanding warrants with a weighted average exercise price of $2.60 per share. To the extent that these outstanding options and warrants are ultimately exercised, you will incur further dilution. For a further description of the dilution that you will experience immediately after this offering, see the "Dilution" section of this prospectus.

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If securities or industry analysts do not publish or cease publishing research or reports about us, our business or our market, or if they change their recommendations regarding our stock adversely, our stock price and trading volume could decline.

        The trading market for our common stock will be influenced by the research and reports that industry or securities analysts may publish about us, our business, our market or our competitors. If any of the analysts who may cover us change their recommendation regarding our stock adversely, or provide more favorable relative recommendations about our competitors, our stock price would likely decline. If any analyst who may cover us were to cease coverage of our company or fail to regularly publish reports on us, we could lose visibility in the financial markets, which in turn could cause our stock price or trading volume to decline.

Our management will have broad discretion over the use of the proceeds we receive in this offering and might not apply the proceeds in ways that increase the value of your investment.

        Our management will have broad discretion in the application of the net proceeds from this offering, and you will be relying on the judgment of our management regarding the application of these proceeds. Our management might not apply our net proceeds of this offering in ways that increase the value of your investment. We expect to use the net proceeds to us from this offering for working capital and other general corporate purposes, which may in the future include expansion of production facilities and HPC platform and equipment, investments in, or acquisitions of, complementary businesses, joint ventures, partnerships, services, intellectual property or technologies. Our management might not be able to yield a significant return, if any, on any investment of these net proceeds. You will not have the opportunity to influence our decisions on how to use our net proceeds from this offering.

After the completion of this offering, we do not expect to declare any dividends in the foreseeable future.

        After the completion of this offering, we do not anticipate declaring any cash dividends to holders of our common stock in the foreseeable future. Consequently, investors may need to rely on sales of their common stock after price appreciation, which may never occur, as the only way to realize any future gains on their investment. Investors seeking cash dividends should not purchase our common stock.

Anti-takeover provisions contained in our certificate of incorporation and bylaws, as well as provisions of Delaware law, could impair a takeover attempt.

        Our amended and restated certificate of incorporation and our amended and restated bylaws to be effective upon the completion of this offering will contain provisions that could delay or prevent a change in control of our company. These provisions could also make it more difficult for stockholders to elect directors and take other corporate actions. These provisions include:

•

staggered board of directors;



•

authorizing the board to issue, without stockholder approval, preferred stock with rights senior to those of our common stock;



•

authorizing the board to amend our bylaws and to fill board vacancies until the next annual meeting of the stockholders;



•

prohibiting stockholder action by written consent;



•

limiting the liability of, and providing indemnification to, our directors and officers;



•

eliminating the ability of our stockholders to call special meetings; and



•

requiring advance notification of stockholder nominations and proposals.

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        Section 203 of the Delaware General Corporation Law prohibits, subject to some exceptions, "business combinations" between a Delaware corporation and an "interested stockholder," which is generally defined as a stockholder who becomes a beneficial owner of 15% or more of a Delaware corporation's voting stock, for a three-year period following the date that the stockholder became an interested stockholder.

        These and other provisions in our amended and restated certificate of incorporation and our amended and restated bylaws to be effective upon the completion of this offering under Delaware law could discourage potential takeover attempts, reduce the price that investors might be willing to pay in the future for shares of our common stock and result in the market price of our common stock being lower than it would be without these provisions. See "Description of Capital Stock—Preferred Stock" and "Description of Capital Stock—Anti-Takeover Provisions."

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FORWARD-LOOKING STATEMENTS

        This prospectus contains forward-looking statements that involve risks and uncertainties. The forward-looking statements are contained principally in the sections entitled "Prospectus Summary," "Risk Factors," "Management's Discussion and Analysis of Financial Condition and Results of Operations" and "Business." These statements relate to future events or our future financial or operational performance and involve known and unknown risks, uncertainties and other factors that could cause our actual results, levels of activity, performance or achievement to differ materially from those expressed or implied by these forward-looking statements. These risks and uncertainties are contained principally in the section entitled "Risk Factors."

        Forward-looking statements include all statements that are not historical facts. In some cases, you can identify forward-looking statements by terms such as "may," "will," "should," "could," "would," "expects," "plans," "anticipates," "believes," "estimates," "projects," "predicts," "potential," or the negative of those terms, and similar expressions and comparable terminology intended to identify forward-looking statements. These statements reflect our current views with respect to future events and are based on assumptions and subject to risks and uncertainties. Given these uncertainties, you should not place undue reliance on these forward-looking statements. These forward-looking statements represent our estimates and assumptions only as of the date of this prospectus and, except as required by law, we undertake no obligation to update or revise publicly any forward-looking statements, whether as a result of new information, future events or otherwise after the date of this prospectus.

MARKET, INDUSTRY AND OTHER DATA

        Unless otherwise indicated, information contained in this prospectus concerning our industry and the markets in which we operate, including our general expectations and market position, market opportunity and market size, is based on information from various sources, on assumptions that we have made that are based on those data and other similar sources and on our knowledge of the markets for our services. These data involve a number of assumptions and limitations, and you are cautioned not to give undue weight to such estimates. We have not independently verified any third party information and cannot assure you of its accuracy or completeness. While we believe the market position, market opportunity and market size information included in this prospectus is generally reliable, such information is inherently imprecise. In addition, projections, assumptions and estimates of our future performance and the future performance of the industry in which we operate is necessarily subject to a high degree of uncertainty and risk due to a variety of factors, including those described in "Risk Factors" and elsewhere in this prospectus. These and other factors could cause results to differ materially from those expressed in the estimates made by the independent parties and by us.

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USE OF PROCEEDS

        We estimate that we will receive net proceeds of approximately $           million from the sale of                shares of common stock offered by us in this offering, based on an assumed initial public offering price of $          per share (the midpoint of the price range set forth on the cover page of this prospectus) and after deducting the underwriting discounts and commissions and estimated offering expenses payable by us. A $1.00 increase (decrease) in the assumed initial public offering price of $          per share would increase (decrease) the net proceeds to us from this offering by $           million, assuming that the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same and after deducting the underwriting discounts and commissions and estimated offering expenses payable by us. If the underwriters' over-allotment option to purchase additional shares from us is exercised in full, we estimate that we will receive additional net proceeds of $           million. We will not receive any proceeds from the sale of the shares of common stock to be offered by the selling stockholders.

        We intend to use the net proceeds received by us from this offering for working capital and other general corporate purposes.

        In connection with an agreement for the purchase of intellectual property and the termination of our royalty obligations under an existing license agreement, we have an obligation to issue a promissory note to Symyx Technologies, Inc. (Symyx), a wholly-owned subsidiary of Accelrys, Inc., upon the consummation of this offering to the extent the gross proceeds from Symyx's sale of                    shares in this offering (before deducting underwriting discounts and commissions and estimated offering expenses) are less than $67 million. At an assumed initial public offering price of $          per share (the midpoint of the price range set forth on the cover page of this prospectus), the gross proceeds from the sale of Symyx's shares would be $             million, and we would have a $                obligation to Symyx. A $1.00 increase (decrease) in the assumed initial public offering price of $          per share would increase (decrease) the gross proceeds to Symyx by $                 million. Such note, if issued, would have a term of 24 months and an interest rate equal to 4%. Such note would be payable in an amount equal to the lesser of the principal amount and the greater of $500,000 per quarter or the amount of accrued interest, with a balloon payment at maturity if applicable. Such note would also be pre-payable by us at any time without penalty or premium, and would be secured by tangible personal property, excluding intellectual property. If we issue such note, a portion of the net proceeds of this offering would be used to make payments of scheduled interest and payment of principal at any time at or prior to maturity. We have also agreed to reimburse Symyx for 50% of their underwriting discounts and commissions.

        We may also use a portion of the net proceeds to expand our current business through acquisitions of other businesses, products, intellectual property or technologies. Other than as set forth above, we do not have agreements or commitments for any specific acquisitions at this time.

        Pending the use of the net proceeds from this offering, we plan to invest the net proceeds in short- and intermediate-term, interest-bearing obligations, investment-grade instruments, certificates of deposit or director or guaranteed obligations of the U.S. government. We cannot predict whether the proceeds invested will yield a favorable return, if any.

DIVIDEND POLICY

        We have never declared or paid any cash dividends on our common stock. We currently intend to retain any future earnings for use in the operation and expansion of our business, and currently do not plan to declare or pay any dividends on shares of our common stock in the foreseeable future. Subject to the foregoing, the payment of cash dividends in the future, if any, will be at the discretion of our board of directors and will depend upon a number of factors, including our earnings, capital requirements, requirements under the Delaware General Corporation Law, restrictions and covenants pursuant to any credit facilities we may enter into, our overall financial condition and any other factors deemed relevant by our board of directors.

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CAPITALIZATION

        The following table sets forth our capitalization as of June 30, 2011 as follows:

•

on an actual basis;



•

on a pro forma basis to reflect:



•

the conversion of all outstanding shares of our redeemable convertible preferred stock into 58,461,447 shares of common stock in connection with the consummation of this offering;



•

the resulting reclassification of accumulated accretion of redeemable convertible preferred stock and preferred stock warrant liability to additional paid-in capital;



•

the conversion of a warrant for redeemable convertible preferred stock into a warrant to purchase 168,747 shares of our common stock at an exercise price of $0.44 per share immediately before the consummation of this offering, and the resulting reclassification of the preferred stock warrant liability to additional paid-in capital; and



•

the cash exercise of certain warrants outstanding to purchase shares of our common stock as of June 30, 2011, resulting in the issuance of 2,621,985 shares of common stock for an aggregate exercise price of approximately $6.4 million.



•

on a pro forma as adjusted basis after further giving effect to the filing of our amended and restated certificate of incorporation and the issuance of a promissory note payable to Symyx in connection with the consummation of the Symyx asset purchase transaction in the event Symyx's gross proceeds from this offering are less than $67 million, each of which will occur in connection with the consummation of this offering, and the receipt of the net proceeds from the sale of                    shares of common stock offered by us in this offering at an assumed initial public offering price of $          per share (the midpoint of the price range set forth on the cover page of this prospectus), after deducting the underwriting discounts and commissions and estimated offering expenses payable by us.

        The pro forma and pro forma as adjusted information below is illustrative only and our capitalization following the completion of this offering will be adjusted based on the actual initial public offering price and other terms of this offering determined at pricing. You should read this table in conjunction with the sections titled "Selected Consolidated Financial Data" and "Management's

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Discussion and Analysis of Financial Condition and Results of Operations" and our consolidated financial statements and related notes included elsewhere in this prospectus.

        In connection with the consummation of the Symyx asset purchase transaction, which will occur in connection with the consummation of this offering, in the event Symyx's gross proceeds from this offering are less than $67 million, we will issue a note payable to Symyx with a value equal to the difference between Symyx's gross proceeds and $67 million.

        If the underwriters' over-allotment option were exercised in full, pro forma as adjusted cash and cash equivalents, common stock and additional paid-in capital, stockholders' equity (deficit) and shares issued and outstanding as of June 30, 2011 would be $           million, $           million, $           million and                    shares, respectively.

        A $1.00 increase (decrease) in the assumed initial public offering price of $          per share (the midpoint of the price range set forth on the cover page of this prospectus) would increase (decrease) the pro forma as adjusted note payable by approximately $           million, each of pro forma as adjusted additional paid-in capital and stockholders' equity (deficit) by approximately $           million and pro forma as adjusted total capitalization by approximately $           million, assuming that the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same. We may also increase or decrease the number of shares we are offering. An increase (decrease) of 1,000,000 in the number of shares we are offering would increase (decrease) each of pro forma as adjusted additional paid-in capital, stockholders' equity (deficit) and total capitalization by approximately $           million, assuming the assumed initial public offering price per share (the midpoint of the price range set forth on the cover page of this prospectus) remains the same. An increase of 1,000,000 in the number of shares we are offering, together with a $1.00 increase in the assumed initial public offering price per share, would increase the pro forma as adjusted note payable by approximately $           million, each of pro forma as adjusted additional paid-in capital and stockholders' equity (deficit) by approximately $           million and pro forma as adjusted total capitalization by approximately $           million. A

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decrease of 1,000,000 in the number of shares we are offering, together with a $1.00 decrease in the assumed initial public offering price per share, would decrease the pro forma as adjusted note payable by approximately $           million, each of pro forma as adjusted additional paid-in capital and stockholders' equity (deficit) by approximately $           million and pro forma as adjusted total capitalization by approximately $           million. The pro forma as adjusted information is illustrative only, and we will adjust this information based on the actual initial public offering price and other terms of this offering determined at pricing.

        The number of actual, pro forma and pro forma as adjusted shares of common stock issued and outstanding in the table above each excludes the following shares as of June 30, 2011:

•

16,403,610 shares of common stock issuable upon the exercise of options outstanding, at a weighted average exercise price of $1.09 per share;



•

1,824,736 shares of common stock issuable upon the exercise of warrants outstanding (not including those to be exercised in connection with the completion of this offering), at a weighted average exercise price of $2.84 per share;



•

236,157 shares of common stock reserved for future issuance under our 2004 Equity Incentive Plan, which will become available for issuance under our 2011 Incentive Award Plan after completion of this offering; and



•

shares of common stock that will be reserved for future issuance under our 2011 Incentive Award Plan, as well as any automatic increases in the number of shares of our common stock reserved for future issuance under this benefit plan, which will become effective immediately prior to the consummation of this offering.

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DILUTION

        If you invest in our common stock in this offering, your interest will be diluted to the extent of the difference between the initial public offering price per share of our common stock and the pro forma as adjusted net tangible book value per share of our common stock immediately after this offering.

        Net tangible book value per share is determined by dividing our total tangible assets less our total liabilities by the number of shares of common stock outstanding. Our historical net tangible book value (deficit) as of June 30, 2011 was $(75.8) million, or $(6.56) per share.

        Our pro forma net tangible book value (deficit) as of June 30, 2011 was $53.3 million, or $0.73 per share, after giving effect to the following:

•

the conversion of all outstanding shares of our redeemable convertible preferred stock into 58,461,447 shares of common stock in connection with the consummation of this offering;



•

the resulting reclassification of accumulated accretion of redeemable convertible preferred stock and preferred stock warrant liability to additional paid-in capital;



•

the conversion of a warrant for redeemable convertible preferred stock into a warrant to purchase 168,477 shares of our common stock at an exercise price of $0.44 per share immediately before the consummation of this offering, and the resulting reclassification of the preferred stock warrant liability to additional paid-in capital;



•

the cash exercise of certain warrants outstanding to purchase shares of our common stock as of June 30, 2011, resulting in the issuance of 2,621,985 shares of common stock for an aggregate exercise price of approximately $6.4 million; and



•

no exercise of the underwriters' over-allotment option.

        After further giving effect to the filing of our amended and restated certificate of incorporation and the issuance of a promissory note payable to Symyx in connection with the consummation of the Symyx asset purchase transaction in the event Symyx's gross proceeds from this offering are less than $67 million, each of which will occur in connection with the consummation of this offering, and our receipt of the net proceeds from the sale of                    shares of common stock offered by us in this offering at an assumed initial public offering price of $          per share (the midpoint of the price range set forth on the cover page of this prospectus), after deducting the underwriting discounts and commissions and estimated offering expenses payable by us, our pro forma as adjusted net tangible book value as of June 30, 2011 would have been $           million, or $          per share. This represents an immediate increase in net tangible book value of $          per share to existing stockholders and an immediate dilution in net tangible book value of $          per share to purchasers of common stock in this offering, as illustrated in the following table:

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        If the underwriters' over-allotment option to purchase additional shares from us is exercised in full, the pro forma as adjusted net tangible book value per share after this offering would be $          per share, the increase in pro forma as adjusted net tangible book value per share to existing stockholders would be $          per share and the dilution to new investors purchasing shares in this offering would be $          per share.

        A $1.00 increase (decrease) in the assumed initial public offering price of $          per share (the midpoint of the price range set forth on the cover page of this prospectus) would increase (decrease) our pro forma as adjusted net tangible book value by $           million, the pro forma as adjusted net tangible book value per share by $          per share and the dilution in the pro forma net tangible book value to new investors in this offering by $          per share and the dilution in the pro forma net tangible book value to new investors purchasing shares in this offering by $          per share, assuming the number of shares offered by us, as set forth on the cover page of this prospectus, remains the same and after deducting the underwriting discounts and commissions and estimated offering expenses payable by us.

        The following table presents on a pro forma as adjusted basis as of June 30, 2011, after giving effect to the pro forma adjustments described above, the differences between the existing stockholders and the new investors purchasing shares in this offering with respect to the number of shares purchased from us, the total consideration paid, which includes net proceeds received from the issuance of common and redeemable convertible preferred stock, cash received from the exercise of stock options and the value of any stock issued for services and the average price paid per share:

        The sale by the selling stockholders in this offering will cause the number of shares held by existing stockholders to be reduced to            shares or        % of the total number of shares of our common stock outstanding after this offering. If the underwriters exercise their over-allotment option in full, our existing stockholders would own         % and our new investors would own        % of the total number of shares of our common stock outstanding after this offering.

        The foregoing calculations are based on 72,639,388 shares of common stock outstanding as of June 30, 2011, assuming the conversion of all outstanding shares of our redeemable convertible preferred stock into 58,461,447 shares of common stock in connection with the consummation of this offering and the cash exercise of certain warrants outstanding to purchase shares of our common stock as of June 30, 2011, resulting in the issuance of 2,621,985 shares of common stock for an aggregate exercise price of approximately $6.4 million, and exclude the following:

•

16,403,610 shares of common stock issuable upon the exercise of options outstanding, at a weighted average exercise price of $1.09 per share;



•

1,824,736 shares of common stock issuable upon the exercise of warrants outstanding (not including those to be exercised in connection with the completion of this offering), at a weighted average exercise price of $2.84 per share;



•

236,157 shares of common stock reserved for future issuance under our 2004 Equity Incentive Plan, which will become available for issuance under our 2011 Incentive Award Plan after completion of this offering; and

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•

                   shares of common stock that will be reserved for future issuance under our 2011 Incentive Award Plan, as well as any automatic increases in the number of shares of our common stock reserved for future issuance under this benefit plan, which will become effective immediately prior to the consummation of this offering.

        To the extent that outstanding options or warrants are exercised, you will experience further dilution. If all of our outstanding options and warrants were exercised, our pro forma net tangible book value as of June 30, 2011 would have been $         million, or $        per share, and the pro forma, as adjusted net tangible book value after this offering would have been $         million, or $        per share, causing dilution to new investors of $        per share.

        In addition, we may choose to raise additional capital due to market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans. To the extent that we raise additional capital through the sale of equity or convertible debt securities, the issuance of these securities could result in further dilution to our stockholders.

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SELECTED CONSOLIDATED FINANCIAL DATA

        The selected consolidated statement of operations data for the years ended December 31, 2008, 2009 and 2010 and the consolidated balance sheet data as of December 31, 2009 and 2010 are derived from our audited consolidated financial statements included elsewhere in this prospectus. The selected consolidated statement of operations data for the six months ended June 30, 2010 and 2011 and the consolidated balance sheet data as of June 30, 2011 are derived from our unaudited consolidated financial statements included elsewhere in this prospectus. The selected consolidated statement of operations data for the years ended December 31, 2006 and 2007 and the consolidated balance sheet data as of December 31, 2006, 2007 and 2008 are derived from our audited consolidated financial statements which are not included in this prospectus. The unaudited interim consolidated financial statements include, in the opinion of management, all adjustments, which consist only of normal recurring adjustments, that management considers necessary for the fair statement of the financial information set forth in those statements. Our historical results are not necessarily indicative of the results that may be expected in the future. You should read the following selected consolidated historical financial data below in conjunction with the section titled "Management's Discussion and Analysis of Financial Condition and Results of Operations" and the consolidated financial statements and related notes included elsewhere in this prospectus.

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