Risk Factors

Investing in our common stock involves a high degree of risk. You should carefully consider each of the following risk factors and all of the other information set forth in this prospectus, including our consolidated financial statements and related notes, before investing in our common stock. The following risks and the risks described elsewhere in this prospectus, including in the section entitled “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” could materially harm our business, prospects, financial condition, future results and cash flow. If that occurs, the trading price of our common stock could decline, and you could lose all or part of your investment.

Risks Relating to Our Business

We face significant competition and expect to face increasing competition in many aspects of our business, which could cause our operating results to suffer.

The market for low-volume custom parts manufacturing is fragmented, highly competitive and subject to rapid and significant technological change. We compete for customers with a wide variety of custom parts manufacturers and methods. Some of our current and potential competitors include captive in-house services, other custom manufacturers, and alternative manufacturing vendors such as those utilizing stereolithography, selective laser sintering, fused deposition modeling and 3D printing. Moreover, some of our existing and potential competitors are researching, designing, developing and marketing other types of products and services. We also expect that future competition may arise from the development of allied or related techniques for custom parts manufacturing that are not encompassed by our patents, from the issuance of patents to other companies that may inhibit our ability to develop certain products and from improvements to existing technologies. And our competitors may attempt to adopt and improve upon key aspects of our business model, such as development of technology that automates much of the manual labor conventionally required to quote and manufacture low-volume custom parts, implementation of interactive web-based and automated user interface and quoting systems and/or building scalable operating models specifically designed for efficient low-volume production. Third-party CAD software companies may develop software that mold-makers, injection molders and CNC machine shops could use to compete with our business model. Additive manufacturers may develop stronger, higher temperature resins or introduce other improvements that could more effectively compete with us on part quality. We may also, from time to time, establish alliances or relationships with other competitors or potential competitors. To the extent companies terminate such relationships and establish alliances and relationships with our competitors, our business could be harmed.

Existing and potential competitors may have substantially greater financial, technical, sales and marketing, manufacturing, distribution and other resources and name recognition than us, as well as experience and expertise in intellectual property rights and operating within certain international locations, any of which may enable them to compete effectively against us.

Though we plan to continue to expend resources to develop new technologies, processes and services, we cannot assure you that we will be able to maintain our current position or continue to compete successfully against current and future sources of competition. Our challenge in developing new services is finding services for which our automated quotation and manufacturing processes offer an attractive value proposition, and we may not be able to find any new services with potential economies of scale similar to our molding and machining services. If we do not keep pace with technological change and introduce new technologies, processes and services, the demand for our products and services may decline and our operating results may suffer.

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Our success depends on our ability to deliver products and services that meet the needs of product developers and to effectively respond to changes in our industry.

We derive almost all of our revenue from the manufacture and sale to product developers of quick-turn low volumes of custom parts for prototyping, support of internal manufacturing and limited quantity product release. Our business has been and we believe will continue to be affected by changes in product developer requirements and preferences, rapid technological change, new product and service introductions and the emergence of new standards and practices, any of which could render our technology, products and services less attractive, uneconomical or obsolete. To the extent that our customers’ need for quick-turn parts decreases for any reason, it would likely have a material adverse affect on our business and operating results and harm our competitive position. In addition, CAD simulation and other technologies may reduce the demand for physical prototype parts. Therefore, we believe that to remain competitive, we must continually expend resources to enhance and improve our technology, product offerings and services.

In particular, we plan to increase our research and development efforts and to continue to focus a significant portion of those efforts to further develop our technology in areas such as our interactive user interface and manufacturing processes, potentially introduce new manufacturing processes and broaden the range of parts that we are able to manufacture. We believe successful execution of this part of our business plan is critical for our ability to compete in our industry and grow our business, and there are no guarantees we will be able to do so in a timely fashion, or at all. Broadening the range of parts we offer is of particular importance since limitations in manufacturability are the primary reason we are not able to fulfill many quotation requests. There are no guarantees that the resources devoted to executing on this aspect of our business plan will improve our business and operating results or result in increased demand for our products and services. Failures in this area could adversely impact our operating results and harm our reputation and brand. And even if we are successful in executing in these areas, our industry is subject to rapid and significant technological change, and our competitors may develop new technologies, processes and services that are superior to ours.

Any failure to properly meet the needs of product developers or respond to changes in our industry on a cost-effective and timely basis, or at all, would likely have a material adverse affect on our business and operating results and harm our competitive position.

Our failure to meet our product developers’ expectations regarding quick turnaround time would adversely affect our business and results of operations.

We believe many product developers are facing increased pressure from global competitors to be first to market with their finished products, often resulting in a need for quick turnaround of custom parts. We believe our ability to quickly quote, manufacture and ship custom parts has been an important factor in our results to date. There are no guarantees we will be able to meet product developers’ increasing expectations regarding quick turnaround time, especially as we increase the scope of our operations. If we fail to meet our customers’ expectations regarding turnaround time in any given period, our business and results of operations will likely suffer.

Our failure to meet our product developers’ price expectations would adversely affect our business and results of operations.

Demand for our services is sensitive to price. We believe our competitive pricing has been an important factor in our results to date. Therefore, changes in our pricing strategies can have a significant impact on our business and ability to generate revenue. Many factors, including our production and personnel costs and our competitors’ pricing and marketing strategies, can significantly impact our pricing strategies. If we fail to meet our customers’ price expectations in any given period, demand for our products and services could be negatively impacted and our business and results of operations could suffer.

The strength of our brand is important to our business, and any failure to maintain and enhance our brand would hurt our ability to retain and expand our customer base as well as further penetrate existing customers.

Since our products and services are sold primarily through our websites, the success of our business depends upon our ability to attract new and repeat customers to our websites in order to increase business and grow our revenue. Customer awareness of, and the perceived value of, our brand will depend largely on the success of our marketing

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efforts, as well as our ability to consistently provide quality custom parts within the required timeframes and positive customer experiences, which we may not do successfully. A primary component of our business strategy is the continued promotion and strengthening of our brand, and we have incurred and plan to continue to incur substantial expense related to advertising and other marketing efforts directed toward enhancing our brand. We have initiated marketing efforts through social media, but this method of marketing may not be successful and subjects us to a greater risk of inconsistent messaging and bad publicity. We may choose to increase our branding expense materially, but we cannot be sure that this investment will be profitable. If we are unable to successfully maintain and enhance our brand, this could have a negative impact on our business and ability to generate revenue.

Our business depends in part on our ability to process a large volume of new part designs from a diversity of product developers and successfully identify significant opportunities for our business based on those submissions.

We believe the volume of new part designs we process and the size and diversity of our customer base give us valuable insight into the needs of our prospective customers. We utilize this industry knowledge to determine where we should focus our development resources. If the number of new part designs we process or the size and diversity of our customer base decrease, our ability to successfully identify significant opportunities for our business and meet the needs of product developers could be negatively impacted. In addition, even if we do continue to process a large number of new part designs and work with a significant and diverse customer base, there are no guarantees that any industry knowledge we extract from those interactions will be successfully utilized to help us identify significant business opportunities or better understand the needs of product developers.

The loss of one or more key members of our management team or personnel, or our failure to attract, integrate and retain additional personnel in the future, could harm our business and negatively affect our ability to successfully grow our business.

We are highly dependent upon the continued service and performance of the key members of our management team and other personnel. The loss of any of these individuals, each of whom is “at will” and may terminate his or her employment relationship with us at any time, could disrupt our operations, harm our reputation and brand, and significantly delay or prevent the achievement of our business objectives. Moreover, some of the members of our management are new to our team. We believe that our future success will also depend in part on our continued ability to identify, hire, train and motivate qualified personnel. For example, we are seeking to hire a significant number of personnel for manufacturing positions in 2012. We conduct our operations in the United States at our facilities in Maple Plain, Minnesota, approximately 20 miles west of downtown Minneapolis. A possible shortage of qualified individuals in this region might require us to pay increased compensation to attract and retain key employees, thereby increasing our costs. In addition, we face intense competition for qualified individuals from numerous companies, many of whom have substantially greater financial and other resources and name recognition than us. We may be unable to attract and retain suitably qualified individuals who are capable of meeting our growing operational, managerial and other requirements, or we may be required to pay increased compensation in order to do so. Our failure to attract, hire, integrate and retain qualified personnel could impair our ability to achieve our business objectives.

If we fail to grow our business as anticipated, our net sales and profitability will be adversely affected.

We are attempting to grow our business substantially. To this end, we have made and expect to continue to make significant investments in our business, including investments in our infrastructure, technology, and sales and marketing efforts. These investments include dedicated facilities expansion and increased staffing, both domestic and international. If our business does not generate the level of revenue required to support our investment, our net sales and profitability will be adversely affected.

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If we are unable to manage our growth and expand our operations successfully, our reputation and brand may be damaged, and our business and results of operations may be harmed.

Over the past several years, we have experienced rapid growth. For example, we have grown from approximately 230 full-time employees as of January 1, 2008 to 511 full-time employees as of December 31, 2011. We have expanded internationally, including establishing manufacturing operations in Europe in 2005 and in Japan in late 2009. In 2011, we added a number of key individuals to our organization. We expect this growth to continue and accelerate and the number of countries and facilities from which we operate to continue to increase in the future. Our ability to effectively manage our anticipated growth and expansion of our operations will require us to do, among other things, the following:

These enhancements and improvements will require significant capital expenditures and allocation of valuable management and employee resources. And our growth, combined with the geographical dispersion of our operations, has placed, and will continue to place, a strain on our operational, financial and management infrastructure. Our future financial performance and our ability to execute on our business plan will depend, in part, on our ability to effectively manage any future growth and expansion. There are no guarantees we will be able to do so in an efficient or timely manner, or at all. Our failure to effectively manage growth and expansion could have a material adverse effect on our business, results of operations, financial condition, prospects, and reputation and brand, including impairing our ability to perform to our customers’ expectations.

We may not timely and effectively scale and adapt our existing technology, processes and infrastructure to meet the needs of our business.

A key element to our continued growth is the ability to quickly and efficiently quote an increasing number of product developer submissions across geographies and to manufacture the related parts. This will require us to timely and effectively scale and adapt our existing technology, processes and infrastructure to meet the needs of our business. With respect to our websites and quoting technology, it may become increasingly difficult to maintain and improve their performance, especially during periods of heavy usage and as our solutions become more complex and our user traffic increases across geographies. Similarly, our manufacturing automation technology may not enable us to process the large numbers of unique designs and efficiently manufacture the related parts in a timely fashion to meet the needs of product developers as our business continues to grow. Any failure in our ability to timely and effectively scale and adapt our existing technology, processes and infrastructure could negatively impact our ability to retain existing customers and attract new customers, damage our reputation and brand, result in lost revenue, and otherwise substantially harm our business and results of operations.

If we are unable to maintain our gross margin from sales of our products, our profitability will be adversely affected.

Our current business plan entails increasing our sales and the scope of our operations while maintaining relatively high gross margin. However, there is no guarantee we will be successful in doing so. Pricing pressure could require us to lower the prices we charge our customers. A number of factors may increase our direct costs. Any inability to maintain our gross margin will have an adverse effect on our profitability and may result in a decrease in our stock price.

Numerous factors may cause us not to maintain the revenue growth that we have historically experienced.

Although our revenue has grown from $35.9 million for the year ended December 31, 2007 to $98.9 million for the year ended December 31, 2011, we likely will not be able to maintain our historical rate of revenue growth. We

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believe that our continued revenue growth will depend on many factors, a number of which are out of our control, including among others, our ability to:

We cannot assure you that we will be successful in continuing to grow our business and revenue, and in addressing the factors above.

Our operating results and financial condition may fluctuate on a quarterly and annual basis.

Our operating results and financial condition may fluctuate from quarter to quarter and year to year, and are likely to continue to vary due to a number of factors, some of which are outside of our control. And our operating results may fail to match our past performance. These events could in turn cause the market price of our common stock to fluctuate. If our operating results do not meet the expectations of securities analysts or investors, who may derive their expectations by extrapolating data from recent historical operating results, the market price of our common stock will likely decline.

Our operating results and financial condition may fluctuate due to a number of factors, including those listed below and those identified throughout this “Risk Factors” section:

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Due to all of the foregoing factors and the other risks discussed in this “Risk Factors” section, you should not rely on quarter-to-quarter or year-to-year comparisons of our operating results as an indicator of future performance.

Interruptions to or other problems with our website and interactive user interface, information technology systems, manufacturing processes or other operations could damage our reputation and brand and substantially harm our business and results of operations.

The satisfactory performance, reliability, consistency, security and availability of our websites and interactive user interface, information technology systems, manufacturing processes and other operations are critical to our reputation and brand, and our ability to effectively service product developers. Any interruptions or other problems that cause any of our websites, interactive user interface or information technology systems to malfunction or be unavailable, or negatively impact our manufacturing processes or other operations, may damage our reputation and brand, result in lost revenue, cause us to incur significant costs seeking to remedy the problem and otherwise substantially harm our business and results of operations.

A number of factors or events could cause such interruptions or problems, including among others: human and software errors, design faults, challenges associated with upgrades, changes or new facets of our business, power loss, telecommunication failures, fire, flood, extreme weather, political instability, acts of terrorism, war, break-ins and security breaches, contract disputes, labor strikes and other workforce related issues, capacity constraints due to an unusually large number of product developers accessing our websites or ordering parts at the same time, and other similar events. These risks are augmented by the fact that our customers come to us largely for our quick-turn manufacturing capabilities and that accessibility and turnaround speed are often of critical importance to these product developers. We are dependent upon our facilities through which we satisfy all of our production demands and in which we house all of the computer hardware necessary to operate our websites and systems as well as managerial, customer service, sales, marketing and other similar functions, and we have not identified alternatives to these facilities or established fully redundant systems in multiple locations. We have back-up computing systems for our U.S. and Japanese operations, but we only have one computing system in the United Kingdom. In the event of a significant shutdown of our U.K. computing system, manufacturing operations in the United Kingdom could be affected for an extended period, delaying shipments and adversely affecting our operating results. In addition, we are dependent in part on third parties for the implementation and maintenance of certain aspects of our communications and production systems, and therefore preventing, identifying and rectifying problems with these aspects of our systems is to a large extent outside of our control.

Moreover, the business interruption insurance that we carry may not be sufficient to compensate us for the potentially significant losses, including the potential harm to the future growth of our business, that may result from interruptions in our service as a result of system failures.

Global economic conditions may harm our ability to do business, increase our costs and negatively affect our stock price.

We believe the global recession in 2008 and 2009 was a major factor in our revenue decreasing 1.4% and our income from operations decreasing 25.8% in 2009 compared to 2008. Though we believe that we are emerging from this global recession, which caused failures of financial institutions and led to government intervention in the United States, Europe, Asia and other regions of the world, we currently face additional global challenges, including those associated with rising government debt levels in a number of countries. The prospects for economic growth in the United States and other countries remain uncertain and could worsen. Economic concerns and other issues such as reduced access to capital for businesses may cause product developers to further delay or reduce the product development projects that our business supports. Given the continued uncertainty concerning the global economy, we face risks that may arise from financial difficulties experienced by our suppliers and product developers and other related risks to our business.

We operate a global business that exposes us to additional risks.

We have established our operations in the United States, Europe and Japan and are seeking to further expand our international operations. As of December 31, 2011, we had sold products into more than 50 countries. In addition

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to English, our website is available in British English, French, German, Italian, Japanese and Spanish. Our international revenue accounted for approximately 26% of our total revenue in each of the years ended December 31, 2010 and 2011. The future growth and profitability of our international business is subject to a variety of risks and uncertainties. Many of the following factors have adversely affected our international operations and sales to customers located outside of the United States and may again in the future:

Our business depends on product developers’ demand for our services, the general economic health of current and prospective customers, and companies’ desire or ability to make investments in new products. A deterioration of global, regional or local political, economic or social conditions could affect potential customers in ways that reduce demand for our services, disrupt our manufacturing and sales plans and efforts or otherwise negatively impact our business. Acts of terrorism, wars, public health issues and increased energy costs could disrupt commerce in ways that could impair our ability to get products to our customers and increase our manufacturing and delivery costs. We have not undertaken hedging transactions to cover our foreign currency exposure, and changes in foreign currency exchange rates may negatively impact reported revenue and expenses. In addition, our sales are often made on unsecured credit terms, and a deterioration of political, economic or social conditions in a given country or region could reduce or eliminate our ability to collect accounts receivable in that country or region. In any of these events, our results of operations could be materially and adversely affected.

We face risks in connection with changes in energy expenses and availability.

We depend on various energy products in processes used in our business. Generally, we acquire energy products at market prices and do not use financial instruments to hedge energy prices. As a result, we are exposed to market risks related to changes in energy prices. In addition, many of the customers and industries to whom we market our services are directly or indirectly dependent upon the cost and availability of energy resources. Our business and profitability may be materially and adversely affected to the extent that energy-related expenses increase, both as a result of higher costs of producing, and potentially lower profit margins in selling, our services and because increased energy costs may cause our customers to delay or reduce the product development projects that our

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business supports. In addition, events impacting the availability of energy required to operate our business, such as the recent earthquakes and tsunami in Japan, could disrupt our business and negatively impact our operating results.

If a natural or man-made disaster strikes any of our manufacturing facilities, we will be unable to manufacture our products for a substantial amount of time and our sales will decline.

We manufacture all of our products in five manufacturing facilities, three of which are located in Maple Plain, Minnesota and one of which is located in each of Telford, United Kingdom and Ebina, Japan. These facilities and the manufacturing equipment we use would be costly to replace and could require substantial lead time to repair or replace. We expect to commence manufacturing operations at a facility in Rosemount, Minnesota in the first quarter of 2012. Our facilities may be harmed by natural or man-made disasters, including, without limitation, earthquakes, floods, tornadoes, fires, tsunamis and nuclear disasters. Our Maple Plain facilities are within 25 miles of a nuclear power plant in Monticello, Minnesota and could be affected by an evacuation or accident at such plant. Recently, the earthquakes and tsunami and subsequent problems affecting nuclear power plants in Japan have dramatically impacted Japan’s manufacturing capacity and business activities. These events impacted our operations in Japan. The long-term effect of these events is still uncertain, and we may continue to experience operational challenges in Japan. In addition, if these circumstances should worsen, our business plan and future revenue and profitability could be further negatively affected.

In the event any of our facilities are affected by a disaster, we may:

Although we possess insurance for damage to our property and the disruption of our business from casualties, this insurance may not be sufficient to cover all of our potential losses and may not continue to be available to us on acceptable terms, or at all.

We depend on the continued growth of product developers’ e-commerce expectations when working with their custom parts manufacturers and their migration from 2D to 3D CAD software.

The business of selling custom parts over the Internet via an interactive web-based and automated user interface and quoting system is not widespread in our industry. Moreover, many product developers still utilize 2D CAD software. Concerns about privacy and technological and other problems may discourage some product developers from adopting the Internet as the medium for procuring their custom parts or adopting 3D CAD software, particularly in countries where e-commerce and 3D CAD software are not as prevalent as they are in our current markets or with product developers in industries not well suited to utilize our services, such as architecture. In order to expand our customer base, we must appeal to and procure customers who historically have used more traditional means of commerce and/or 2D CAD drawings to purchase their customer parts. If product developers are not sufficiently attracted to the value proposition of or satisfied with our web-based interface and quotation system, or product developers do not continue to migrate to 3D CAD software as we currently anticipate, our business could be adversely impacted.

If our present single or limited source suppliers become unavailable or inadequate, our customer relationships, results of operations and financial condition may be adversely affected.

We acquire substantially all of the manufacturing equipment and certain of our materials that are critical to the ongoing operation and future growth of our business from just a few third parties. We do not have long-term supply contracts with any of our suppliers and operate on a purchase-order basis. While most manufacturing equipment and materials for our products are available from multiple suppliers, certain of those items are only available from single or limited sources. Should any of our present single or limited source suppliers for manufacturing equipment or

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materials become unavailable or inadequate, or impose terms unacceptable to us such as increased pricing terms, we could be required to spend a significant amount of time and expense to develop alternate sources of supply, and we may not be successful in doing so on terms acceptable to us, or at all. Natural disasters, such as hurricanes, may affect our supply of materials, particularly resins, from time to time, and we may purchase larger amounts of certain materials in anticipation of future shortages or increases in pricing. For instance, we purchased a two-year supply of carbide blanks, which are used to manufacture end mills used in our CNC machining equipment, because tungsten, a component of carbide, is expected to be in low supply globally for approximately two years. In the third and fourth quarters of 2011, we placed orders totalling approximately $1.3 million for two years’ worth of carbide blanks, based on our current projections, to try to ensure that we have a continuous supply of end mills, but we may still run short and be required to purchase carbide blanks on the open market at likely much higher prices. In addition, if we were unable to find a suitable supplier for a particular type of manufacturing equipment or material, we could be required to modify our existing business processes and offerings to accommodate the situation. As a result, the loss of a single or limited source supplier could adversely affect our relationship with our customers and our results of operations and financial condition.

Our business depends on the development and maintenance of the Internet infrastructure.

The success of our services will depend largely on the development and maintenance of the Internet infrastructure. This includes maintenance of a reliable network backbone with the necessary speed, data capacity, and security, as well as timely development of complementary products, for providing reliable Internet access and services. The Internet has experienced, and is likely to continue to experience, significant growth in the numbers of users and amount of traffic. The Internet infrastructure may be unable to support such demands. In addition, increasing numbers of users, increasing bandwidth requirements, or problems caused by “viruses,” “worms,” malware and similar programs may harm the performance of the Internet. The backbone computers of the Internet have been the targets of such programs. The Internet has experienced a variety of outages and other delays as a result of damage to portions of its infrastructure, and it could face outages and delays in the future. These outages and delays could reduce the level of Internet usage generally as well as the level of usage of our services, which could adversely impact our business.

If the security of our customers’ confidential information stored in our systems is breached or otherwise subjected to unauthorized access, our reputation or brand may be harmed, and we may be exposed to liability.

Our system stores, processes and transmits our customers’ confidential information, including the intellectual property in their part designs, credit card information and other sensitive data. We rely on encryption, authentication and other technologies licensed from third parties, as well as administrative and physical safeguards, to secure such confidential information. Any compromise of our information security could damage our reputation and brand and expose us to a risk of loss, costly litigation and liability that would substantially harm our business and operating results. We may not have adequately assessed the internal and external risks posed to the security of our company’s systems and information and may not have implemented adequate preventative safeguards or take adequate reactionary measures in the event of a security incident. In addition, most states have enacted laws requiring companies to notify individuals and often state authorities of data security breaches involving their personal data. These mandatory disclosures regarding a security breach often lead to widespread negative publicity, which may cause our existing and prospective customers to lose confidence in the effectiveness of our data security measures. Any security breach, whether successful or not, would harm our reputation and brand and could cause the loss of customers.

We may not be able to adequately protect or enforce our intellectual property rights, which could impair our competitive position.

Our success and future revenue growth will depend, in part, on our ability to protect our intellectual property. We rely primarily on patents, licenses, trademarks and trade secrets, as well as non-disclosure agreements and other methods, to protect our proprietary technologies and processes globally. Despite our efforts to protect our proprietary technologies and processes, it is possible that competitors or other unauthorized third parties may obtain, copy, use or disclose our technologies and processes. We cannot assure you that any of our existing or future patents will not be challenged, invalidated or circumvented. As such, any rights granted under these patents may not provide us with meaningful protection. We may not be able to obtain foreign patents corresponding to our U.S. patents. Even if

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foreign patents are granted, effective enforcement in foreign countries may not be available. If our patents and other intellectual property do not adequately protect our technology, our competitors may be able to offer services similar to ours. Our competitors may also be able to develop similar technology independently or design around our patents. Any of the foregoing events would lead to increased competition and lower revenue or gross margin, which would adversely affect our net income.

We may be subject to infringement claims.

We may be subject to intellectual property infringement claims from individuals, vendors and other companies who have acquired or developed patents in the fields of CNC machining, injection molding or part production for purposes of developing competing products or for the sole purpose of asserting claims against us. Any claims that our products or processes infringe the intellectual property rights of others, regardless of the merit or resolution of such claims, could cause us to incur significant costs in responding to, defending and resolving such claims, and may prohibit or otherwise impair our ability to commercialize new or existing products. If we are unable to effectively defend our processes, our market share, sales and profitability could be adversely impacted.

Our failure to expand our intellectual property portfolio could adversely affect the growth of our business and results of operations.

Expansion of our intellectual property portfolio is one of the available methods of growing our revenue and our profits. This involves a complex and costly set of activities with uncertain outcomes. Our ability to obtain patents and other intellectual property can be adversely affected by insufficient inventiveness of our employees, by changes in intellectual property laws, treaties, and regulations, and by judicial and administrative interpretations of those laws treaties and regulations. Our ability to expand our intellectual property portfolio could also be adversely affected by the lack of valuable intellectual property for sale or license at affordable prices. There is no assurance that we will be able to obtain valuable intellectual property in the jurisdictions where we and our competitors operate or that we will be able to use or license that intellectual property.

We may be subject to product liability claims, which could result in material expense, diversion of management time and attention and damage to our business and reputation and brand.

The prototype parts we manufacture and the parts we manufacture in low volumes may contain undetected defects or errors that are not discovered until after the products have been installed and used by customers. This could result in claims from customers or others, damage to our business and reputation and brand, or significant costs to correct the defect or error.

We attempt to include provisions in our agreements with customers that are designed to limit our exposure to potential liability for damages arising from defects or errors in our products. However, it is possible that these limitations may not be effective as a result of unfavorable judicial decisions or laws enacted in the future.

The sale and support of our products entails the risk of product liability claims. Any product liability claim brought against us, regardless of its merit, could result in material expense, diversion of management time and attention, damage to our business and reputation and brand, and cause us to fail to retain existing customers or to fail to attract new customers.

Government regulation of the Internet and e-commerce is evolving, and unfavorable changes or failure by us to comply with these regulations could substantially harm our business and results of operations.

We are subject to general business regulations and laws as well as regulations and laws specifically governing the Internet and e-commerce. Existing and future laws and regulations may impede the growth of the Internet or other online services. These regulations and laws may cover taxation, restrictions on imports and exports, customs, tariffs, user privacy, data protection, pricing, content, copyrights, distribution, electronic contracts and other communications, consumer protection, the provision of online payment services, broadband residential Internet access and the characteristics and quality of products and services. It is not clear how existing laws governing issues such as property use and ownership, sales and other taxes, fraud, libel and personal privacy apply to the Internet and e-commerce, especially where these laws were adopted prior to the advent of the Internet and do not contemplate or address the unique issues raised by the Internet or e-commerce. Those laws that do reference the Internet are being interpreted by the courts and their applicability and reach are therefore uncertain. The costs of compliance with

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these regulations may increase in the future as a result of changes in the regulations or the interpretation of them. Further, any failures on our part to comply with these regulations may subject us to significant liabilities. Those current and future laws and regulations or unfavorable resolution of these issues may substantially harm our business and results of operations.

Changes in, or interpretation of, tax rules and regulations may impact our effective tax rate and future profitability.

We are a U.S. based, multinational company subject to tax in multiple U.S. and foreign tax jurisdictions. Our future effective tax rates could be adversely affected by changes in statutory tax rates or interpretation of tax rules and regulations in jurisdictions in which we do business, changes in the amount of revenue or earnings in the countries with varying statutory tax rates, or by changes in the valuation of deferred tax assets and liabilities.

In addition, we are subject to audits and examinations of previously filed income tax returns by the Internal Revenue Service, or IRS, and other domestic and foreign tax authorities. We regularly assess the potential impact of such examinations to determine the adequacy of our provision for income taxes and have reserved for potential adjustments that may result from the current examinations. We believe such estimates to be reasonable; however, there is no assurance that the final determination of any examination will not have an adverse effect on our operating results and financial position.

We do not collect state sales, use or other taxes outside the State of Minnesota, which could subject us to liability for past sales and any imposition of an obligation to do so in the future could negatively impact our financial results.

We do not collect sales, use, or other state or local taxes on sales of goods shipped to customers located in U.S. states other than Minnesota, which is the only U.S. state in which we have employees, facilities and inventory. We interpret existing judicial rulings to prohibit states in which we are not physically present, and local tax jurisdictions located in such states, from imposing upon us a requirement to collect sales and use taxes. If our interpretation is not correct, or if legislation or future judicial rulings alter the law, including bills currently pending in the U.S. Congress, then we could be required to collect sales and use taxes in the future from all customers. In some cases such obligations could be retroactive. Currently, our customers may be obligated to file a use tax return and pay use tax on taxable purchases of items that we sell when we do not collect the tax. However, it may often be the case that use tax returns are not filed. Thus, if we were required to collect the tax, our customers might perceive the tax to be in the nature of a price increase, which would negatively impact our sales. Collecting the tax would also impose additional administrative burdens on us.

We may require additional capital to support business growth, and this capital might not be available on acceptable terms, if at all.

We intend to continue to make investments to support our business growth and may require additional funds to respond to business challenges, including the need to complement our growth strategy, increase market share in our current markets or expand into other markets, or broaden our technology, intellectual property or service capabilities. Accordingly, we may need to engage in equity or debt financings to secure additional funds. If we raise additional funds through future issuances of equity or convertible debt securities, our existing shareholders could suffer significant dilution, and any new equity securities we issue could have rights, preferences and privileges superior to those of holders of our common stock. Any debt financing we secure in the future could involve restrictive covenants relating to our capital raising activities and other financial and operational matters, which may make it more difficult for us to obtain additional capital and to pursue business opportunities, including potential acquisitions. We may not be able to obtain additional financing on terms favorable to us, if at all. If we are unable to obtain adequate financing or financing on terms satisfactory to us when we require it, our ability to continue to support our business growth and to respond to business challenges could be significantly impaired, and our business may be harmed.

Any acquisition, strategic relationship, joint venture or investment could disrupt our business and harm our operating results and financial condition.

Our business and our customer base have been built primarily through organic growth. However, from time to time, we may selectively pursue acquisitions, strategic relationships, joint ventures or investments that we believe may allow us to complement our growth strategy, increase market share in our current markets or expand into other

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markets, or broaden our technology, intellectual property or service capabilities. We cannot forecast the number, timing or size of such transactions, or the effect that any such transactions might have on our operating or financial results. We have very limited experience engaging in these types of transactions. And such transactions may be complex, time consuming and expensive, and may present numerous challenges and risks including:

Any one of these challenges or risks could impair our ability to realize any benefit from our acquisitions, strategic relationships, joint ventures or investments after we have expended resources on them, as well as divert our management’s attention. And any failure to successfully address these challenges or risks could disrupt our business and harm our operating results and financial condition. Moreover, any such transaction may not be viewed favorably by investors or analysts.

In addition, from time to time we may enter into negotiations for acquisitions, relationships, joint ventures or investments that are not ultimately consummated. These negotiations could result in significant diversion of management time, as well as substantial out-of-pocket costs.

We rely on third parties for certain key services.

We rely on third-party service providers for shipment and certain other services critical to our business, including our phone system and maintenance of our CNC milling machines. If these third parties experience difficulty meeting our requirements or standards, it could damage our reputation and brand, or make it difficult for us to operate some aspects of our business. In addition, if such third parties were to cease operations, temporarily or permanently, face financial distress or other business disruption, we could suffer increased costs and delays in our ability to operate our business until an equivalent provider could be found or we could develop replacement technology or operations, and there is no assurance that we would be able to do so on acceptable financial terms, or at all. In addition, if we are unsuccessful in choosing high quality partners or we ineffectively manage these partners, it could have an adverse impact on our business and financial performance.

We depend in part on licenses of technologies from third parties in order to deliver our solutions, and, as a result, our business is dependent in part on the availability of such licenses on commercially reasonable terms.

We currently, and will continue to, license certain technologies from third parties. We cannot be certain that these third-party content licenses will be available to us on commercially reasonable terms or that we will be able to successfully integrate the technology into our solutions. These third-party in-licenses may expose us to increased risk, including risks associated with the assimilation of new technology sufficient to offset associated acquisition and maintenance costs. The inability to obtain any of these licenses could result in delays in solution development until equivalent technology can be identified and integrated. Any such delays in services could cause our business, operating results and financial condition to suffer.

Our business involves the use of hazardous materials, and we and our suppliers must comply with environmental laws and regulations, which can be expensive and restrict how we do business.

Our business involves the controlled storage, use and disposal of hazardous materials. We and our suppliers are subject to federal, state and local as well as foreign laws and regulations governing the use, manufacture, storage,

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handling and disposal of these hazardous materials. Although we believe that the safety procedures utilized by us and our suppliers for handling and disposing of these materials comply with the standards prescribed by these laws and regulations, we cannot eliminate the risk of accidental contamination or injury from these materials. In the event of an accident, state, federal or foreign authorities may curtail the use of these materials and interrupt our business operations. We do not currently maintain hazardous materials insurance coverage. If we are subject to any liability as a result of activities involving hazardous materials, our business and financial condition may be adversely affected and our reputation and brand may be harmed.

If we are unable to meet regulatory quality standards applicable to our manufacturing and quality processes for the parts we manufacture, our business, financial condition or operating results could be harmed.

As a manufacturer of CNC machined and injection molded custom parts, we are required to meet certain regulatory standards, including International Organization for Standardization, or ISO, 9001:2008 for our manufacturing facilities in Minnesota. If any regulatory inspection reveals that we are not in compliance with applicable standards, regulators may take action against us, including issuing a warning letter, imposing fines on us, requiring a recall of the parts we manufactured or closing our manufacturing facilities. If any of these actions were to occur, it could harm our reputation as well as our business, financial condition and operating results. In addition, we may need to obtain additional certifications in the future and there are no guarantees we would be able to do so on a timely basis, if at all. Moreover, obtaining and maintaining required regulatory certifications can be costly and divert management’s attention.

We are subject to payment-related risks.

We accept payments using a variety of methods, including credit card, customer invoicing, physical bank check and payment upon delivery. As we offer new payment options to our customers, we may be subject to additional regulations, compliance requirements and fraud risk. For certain payment methods, including credit and debit cards, we pay interchange and other fees, which may increase over time and raise our operating costs and lower profitability. We rely on third parties to provide payment processing services, including the processing of credit cards, debit cards or electronic checks, and it could disrupt our business if these companies become unwilling or unable to provide these services to us. We are also subject to payment card association operating rules, certification requirements and rules governing electronic funds transfers, which could change or be reinterpreted to make it difficult or impossible for us to comply. If we fail to comply with these rules or requirements, we may be subject to fines and higher transaction fees and lose our ability to accept credit and debit card payments from our customers, process electronic funds transfers, or facilitate other types of online payments, and our business and operating results could be adversely affected.

Risks Relating to this Offering and Ownership of Our Common Stock

Our principal existing shareholders will continue to own a large percentage of our voting stock after this offering, which may allow them to collectively control substantially all matters requiring shareholder approval.

As of December 31, 2011, our principal existing shareholders beneficially owned approximately 17.6 million shares, or 93% of our capital stock outstanding as of such date (assuming full conversion of our outstanding Series A preferred stock). Upon the completion of this offering, assuming no exercise of the underwriters’ option to purchase additional shares and assuming North Bridge purchases 430,000 shares of our common stock in this offering, our principal existing shareholders will beneficially own approximately 78% of our outstanding shares of common stock. Our principal existing shareholders consist of our founder, Chairman and Chief Technology Officer, Lawrence Lukis; our President and Chief Executive Officer, Bradley Cleveland; North Bridge and Protomold Investment Company, LLC, or PIC, a company affiliated with Private Capital Management, Inc. Each of our principal existing shareholders either is or has designated one or more members of our board of directors. These shareholders could control us through their board representation or through their ability to determine the outcome of the election of our directors, to amend our articles of incorporation and by-laws and to take other actions requiring the vote or consent of shareholders, including mergers, going private transactions and other extraordinary transactions, and the terms of any of these transactions. The ownership positions of these shareholders may have the effect of delaying, deterring or

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preventing a change in control or a change in the composition of our board of directors. These shareholders may also use their large ownership positions to address their own interests, which may be different from those of investors in this offering. In addition, sales of shares beneficially owned by these shareholders could be viewed negatively by third parties and have a negative impact on our stock price.

Participation in this offering by one of our existing principal shareholders would reduce the available public float for our shares.

North Bridge, one of our principal shareholders that is affiliated with a board member, has indicated an interest in purchasing up to approximately 430,000 shares of our common stock in this offering at the initial public offering price. However, because this indication of interest is not a binding agreement or commitment to purchase, our underwriters may determine to sell more, less or no shares in this offering to North Bridge, or North Bridge may determine to purchase more, less or no shares in this offering. If North Bridge were to purchase all of these shares, it would beneficially own approximately 28% of our outstanding common stock after this offering.

If North Bridge is allocated all or a portion of the shares for which it has indicated an interest in this offering and purchases any such shares, such purchase would reduce the available public float for our shares because North Bridge would be restricted from selling the shares by a lock-up agreement it has entered into with our underwriters. As a result, any purchase of shares by North Bridge in this offering may reduce the liquidity of our common stock relative to what it would have been had these shares been purchased by investors that were not affiliated with us.

Our stock price may be volatile or may decline regardless of our operating performance, and you may not be able to resell your shares at or above the initial public offering price.

The initial public offering price for shares of our common stock will be determined by negotiations between us and representatives of the underwriters and may not be indicative of prices that will prevail in the trading market. After this offering, the market price for our common stock is likely to be volatile, in part because our shares have not been traded publicly. In addition, the market price of our common stock may fluctuate significantly in response to a number of factors, many of which are outside of our control, including among others:

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In addition, the stock markets have experienced extreme price and volume fluctuations that have affected and continue to affect the market prices of equity securities of many companies. In the past, shareholders have instituted securities class action litigation following periods of market volatility. If we were to become involved in securities litigation, we could incur substantial costs and our resources and the attention of management could be diverted from our business.

If securities or industry analysts do not publish research or reports, or publish inaccurate or unfavorable research or reports about our business, our stock price and trading volume could decline.

The trading market for our common stock will depend, in part, on the research and reports that securities or industry analysts publish about us or our business. We do not have any control over these analysts. We do not currently have and may never obtain research coverage by securities and industry analysts. If no securities or industry analysts commence coverage of our company, the trading price for our common stock would be negatively impacted. If we obtain securities or industry analyst coverage and if one or more of the analysts who covers us downgrades our common stock, changes their opinion of our shares or publishes inaccurate or unfavorable research about our business, our stock price would likely decline. If one or more of these analysts ceases coverage of us or fails to publish reports on us regularly, demand for our common stock could decrease and we could lose visibility in the financial markets, which could cause our stock price and trading volume to decline.

Future sales of our common stock, or the perception in the public markets that these sales may occur, may depress our stock price.

Sales of substantial amounts of our common stock in the public market after this offering, or the perception that these sales could occur, could adversely affect the price of our common stock and could impair our ability to raise capital through the sale of additional shares. Based on the number of outstanding shares as of December 31, 2011, upon the completion of this offering, we will have 23,187,708 shares of common stock outstanding.

The shares of common stock offered in this offering will be freely tradable without restrictions or further registration under the Securities Act of 1933, as amended, or the Securities Act, except for any shares of our common stock that may be held or acquired by our directors, executive officers and other affiliates, as that term is defined in Rule 144 under the Securities Act. Those securities may not be sold in the public market unless the sale is registered under the Securities Act or an exemption from registration is available.

We, each of our officers and directors, and all of our other shareholders have agreed, subject to certain exceptions, with the underwriters not to dispose of or hedge any of the shares of common stock or securities convertible into or exchangeable for shares of common stock during the period from the date of this prospectus continuing through the date 180 days after the date of this prospectus, subject to certain extensions. Jefferies & Company, Inc. and Piper Jaffray & Co., as representatives of the underwriters, may, in their sole discretion, release some or all of these shares from these restrictions prior to the expiration of the lock-up period, as permitted by the rules of the Financial Industry Regulatory Authority, or FINRA. See “Underwriting.”

The shares of common stock held by existing shareholders as of the date of this prospectus will, from time to time after this offering, become eligible to be sold in the public market, subject to limitations imposed under federal securities laws. See “Shares Eligible for Future Sale” for a more detailed description of the restrictions on selling shares of our common stock after this offering.

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In the future, we may also issue our securities in connection with investments or acquisitions. The amount of shares of our common stock issued in connection with an investment or acquisition could constitute a material portion of our then-outstanding shares of our common stock.

The requirements of being a public company may strain our resources, divert management’s attention and affect our ability to attract and retain qualified board members.

As a public company, we will be subject to the reporting requirements of the Securities Exchange Act of 1934, as amended, or the Exchange Act, the Sarbanes-Oxley Act of 2002, or the Sarbanes-Oxley Act, the Dodd-Frank Wall Street Reform and Consumer Protection Act, the listing requirements of the New York Stock Exchange, or NYSE, and other applicable securities rules and regulations. Compliance with these rules and regulations will increase our legal, financial compliance and other costs, make some activities more difficult, time-consuming or costly and increase demand on our systems and resources, although we are currently unable to estimate these costs with any degree of certainty. The Exchange Act requires, among other things, that we file annual, quarterly and current reports with respect to our business and operating results. The Sarbanes-Oxley Act requires, among other things, that we maintain effective disclosure controls and procedures and internal control over financial reporting. In order to maintain and, if required, improve our disclosure controls and procedures and internal control over financial reporting to meet this standard, significant resources and management oversight may be required. As a result, management’s attention may be diverted from other business concerns, which could harm our business and operating results. Although we have already hired additional employees to comply with these requirements, including our new Chief Financial Officer, we may need to hire more employees in the future, which will increase our costs and expenses.

In addition, changing laws, regulations and standards relating to corporate governance and public disclosure are creating uncertainty for public companies, increasing legal, financial and other compliance costs, and making some activities more time consuming. These laws, regulations and standards are subject to varying interpretations, in many cases due to their lack of specificity, and, as a result, their application in practice may evolve over time as new guidance is provided by regulatory and governing bodies. This could result in continuing uncertainty regarding compliance matters and higher costs necessitated by ongoing revisions to disclosure and governance practices. We intend to invest resources to comply with evolving laws, regulations and standards, and this investment may result in increased general and administrative expenses and a diversion of management’s time and attention from revenue-generating activities to compliance activities. If our efforts to comply with new laws, regulations and standards differ from the activities intended by regulatory or governing bodies due to ambiguities related to practice, regulatory authorities may initiate legal proceedings against us and our business may be harmed.

We also expect that being a public company and these new rules and regulations will make it more difficult and 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. These factors could also make it more difficult for us to attract and retain qualified persons to serve on our board of directors, our board committees (particularly our audit committee and compensation committee), and as our executive officers. Furthermore, if we are unable to satisfy our obligations as a public company, we could be subject to delisting of our common stock, fines, sanctions and other regulatory action and potentially civil litigation.

As a result of disclosure of information in this prospectus and in filings required of a public company, our business and financial condition will become more visible, which we believe may result in threatened or actual litigation, including by competitors and other third parties. If such claims are successful, our business and operating results could be harmed, and even if the claims do not result in litigation or are resolved in our favor, these claims, and the time and resources necessary to resolve them, could divert the resources of our management and harm our business and operating results.

As a result of becoming a public company, we will be obligated to develop and maintain proper and effective internal controls over financial reporting and otherwise comply with Section 404 of the Sarbanes-Oxley Act. This will require significant expenditures and effort by our management, and may not complete our analysis of our internal controls over financial reporting in a timely manner, or these internal controls may not be determined to be effective, which may adversely affect investor confidence in our company and, as a result, the value of our common stock.

Pursuant to Section 404 of the Sarbanes-Oxley Act and related rules and regulations, and beginning with our Annual Report on Form 10-K for the year ending December 31, 2013, our management will be required to report on, and, if

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our market capitalization exceeds $75.0 million, our independent registered public accounting firm to attest to, the effectiveness of our internal control over financial reporting. The rules governing the standards that must be met for management to assess our internal control over financial reporting are complex and require significant documentation, testing and possible remediation. We are currently in the very early stage of the costly and challenging process of reviewing, documenting and testing our internal control over financial reporting. 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 may encounter problems or delays in completing the implementation of any changes necessary to make a favorable assessment of our internal control over financial reporting. In addition, in connection with the attestation process by our independent registered public accounting firm, we may encounter problems or delays in completing the implementation of any requested improvements and receiving a favorable attestation. If we are unable to assert that our internal control over financial reporting is effective, or if our independent registered public accounting firm is unable to express an unqualified opinion on the effectiveness of our internal controls, investors could lose confidence in the accuracy and completeness of our financial information and our stock price could decline.

Anti-takeover provisions in our charter documents and Minnesota law might discourage or delay acquisition attempts for us that you might consider favorable.

Our third amended and restated articles of incorporation and amended and restated by-laws will contain provisions that may make the acquisition of our company more difficult without the approval of our board of directors. These provisions:

We are subject to the provisions of Section 302A.673 of the Minnesota Statutes, which regulates business combinations. Section 302A.673 generally prohibits any business combination by an issuing public corporation, or any of its subsidiaries, with an interested shareholder, which means any shareholder that purchases 10% or more of the corporation’s voting shares within four years following the date the person became an interested shareholder, unless the business combination is approved by a committee composed solely of one or more disinterested members of the corporation’s board of directors before the date the person became an interested shareholder.

These anti-takeover provisions could discourage, delay or prevent a transaction involving a change in control of our company, even if doing so would benefit our shareholders. These provisions could also discourage proxy contests and make it more difficult for you and other shareholders to elect directors of your choosing and to cause us to take other corporate actions you desire.

If you purchase shares of common stock sold in this offering, because the initial public offering price of our common stock will be substantially higher than the pro forma as adjusted net tangible book value per share following this offering, you will incur immediate and substantial dilution.

The initial public offering price will be substantially higher than the pro forma as adjusted net tangible book value per share of our outstanding common stock immediately following this offering based on the total value of our tangible assets less our total liabilities. Therefore, if you purchase shares of our common stock in this offering, you will incur immediate and substantial dilution in the amount of $9.66 per share, the difference between the assumed initial public offering price per share of $14.00, the midpoint of the price range set forth on the cover of this prospectus, and the pro forma as adjusted net tangible book value per share of our outstanding common stock as of December 31, 2011, after giving effect to the full conversion of our Series A preferred stock and the issuance of

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4,300,000 shares of our common stock in this offering. This dilution is due in large part to the fact that our earlier investors paid substantially less than the initial public offering price when they purchased their shares. In addition, you may also experience additional dilution upon future equity and convertible debt issuances or the exercise of stock options to purchase common stock granted to our employees, consultants and directors under our stock option and equity incentive plans. See “Dilution.”

We have broad discretion in the use of the net proceeds from this offering and we may invest or apply them in ways with which you may not agree or in ways which may not yield a return.

The net proceeds from this offering may be used for general corporate purposes, including working capital. We may also use a portion of the net proceeds to acquire complementary businesses, technologies, products or services, though we do not have any agreements or commitments for any such acquisitions at this time. 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 may not apply our net proceeds in ways that ultimately increase the value of your investment. Pending their use, we may invest the net proceeds from this offering in short-term, investment-grade, interest-bearing securities. These investments may not yield a favorable return to our shareholders. If we do not invest or apply the net proceeds from this offering in ways that enhance shareholder value, the price of our common stock could decline.

No public market for our common stock currently exists, and an active public trading market for our common stock may not develop or be sustained following this offering, which could limit your ability to sell your shares of our common stock at an attractive price, or at all.

Prior to this offering, there has been no public market for our common stock. Although we have applied to list our common stock on the NYSE, we cannot predict the extent to which investor interest in our company will lead to the development of an active trading market in our common stock or how liquid that market might become. An active public market for our common stock may not develop or be sustained after the offering. If an active public market does not develop or is not sustained, it may be difficult for you to sell your shares of common stock at a price that is attractive to you, or at all, and that may reduce the fair value of your shares. An inactive market may also impair our ability to raise capital to fund operations by selling shares and my impair our ability to acquire other companies, technologies or services by using our shares as consideration.

We do not expect to pay any cash dividends for the foreseeable future.

We have never declared or paid any cash dividends on our common stock, and we do not anticipate that we will pay any such cash dividends for the foreseeable future. We anticipate that we will retain all of our future earning for use in the business and for general corporate purposes. Any determination to pay dividends in the future will be at the discretion of our board of directors and will depend upon results of operations, financial condition, contractual restrictions, restrictions imposed by applicable law and other factors our board of directors deems relevant. Accordingly, if you purchase shares in this offering, realization of a gain on your investment will depend on the appreciation of the price of our common stock, which may never occur.

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