RISK FACTORS

Investing in our common stock involves a high degree of risk. You should consider carefully the risks and uncertainties described below, together with all of the other information in this prospectus, including the consolidated financial statements and the related notes included elsewhere in this prospectus, before deciding whether to invest in shares of our common stock. If any of the following risks or other risks actually occur, our business, financial condition, results of operations, and future prospects could be materially harmed. In that event, the market price of our common stock could decline, and you could lose part or all of your investment.

Risks Related to Our Business and Industry

Our quarterly and annual results may fluctuate significantly, may not fully reflect the underlying performance of our business and may result in decreases in the price of our common stock.

Our quarterly and annual results of operations, including our revenues, profitability and cash flow may vary significantly in the future and period-to-period comparisons of our operating results may not be meaningful. Accordingly, the results of any one quarter or period should not be relied upon as an indication of future performance. Our quarterly and annual financial results may fluctuate as a result of a variety of factors, many of which are outside our control and, as a result, may not fully reflect the underlying performance of our business. Fluctuation in quarterly and annual results may negatively impact the value of our common stock. Factors that may cause fluctuations in our quarterly and annual results include, without limitation:

11

Table of Contents

If we are unable to attract new clients or sell additional services and functionality to our existing clients, our revenue and revenue growth will be harmed.

To increase our revenue, we must add new clients, encourage existing clients to renew their subscriptions on terms favorable to us and to add additional agent seats and sell additional functionality to existing clients. As our industry matures, or as competitors introduce lower cost and/or differentiated products or services that are perceived to compete favorably with ours, our ability to add new clients and renew or upsell existing clients based on pricing, technology and functionality could be impaired. As a result, we may be unable to renew our agreements with existing clients or attract new clients or new business from existing clients, which could harm our revenue and growth.

A portion of our revenue is generated by acquiring domestic and international telecommunications minutes from wholesale telecommunication service providers and reselling those minutes to our clients. We must resell more minutes if telecommunications rates decrease to maintain our level of usage revenue.

Our recent rapid growth may not be indicative of our future growth, and if we continue to grow rapidly, we may fail to manage our growth effectively.

For the years ended December 31, 2011, 2012 and 2013, our revenue was $43.2 million, $63.8 million and $84.1 million, respectively, representing year-over-year growth of 48% and 32%, respectively. We expect that, in the future, as our revenue increases, our revenue growth rate may decline. We believe growth of our revenue depends on a number of factors, including our ability to:

If we are not successful in achieving these objectives, our revenue may be harmed. In addition, we plan to continue our investment in future growth, including expending substantial financial and other resources on:

Moreover, we have recently experienced a period of rapid growth in our headcount and operations. In particular, we grew from 332 employees as of December 31, 2011, to 442 employees as of December 31, 2012, to 533 employees as of December 31, 2013. We have also significantly increased the size of our client base to over

12

Table of Contents

2,000 clients. We anticipate that we will significantly expand our operations and headcount in the near term. This growth has placed, and future growth will place, a significant strain on our management, administrative, operational and financial infrastructure. Our success will depend in part on our ability to manage this growth effectively. To manage the expected growth of our operations and personnel, we will need to continue to improve our operational, financial and management controls and our reporting systems and procedures. Failure to effectively manage growth could result in difficulty or delays in adding new clients, declines in quality or client satisfaction, increases in costs, system failures, difficulties in introducing new features or solutions or other operational difficulties, and any of these difficulties could harm our business performance and results of operations.

The expected addition of new employees and the capital investments that we anticipate will be necessary to manage our anticipated growth will make it more difficult for us to generate earnings or offset any future revenue shortfalls by reducing costs and expenses in the short term. If we fail to manage our anticipated growth, we will be unable to execute our business plan successfully.

The markets in which we participate are highly competitive, and if we do not compete effectively, our operating results could be harmed.

The market for contact center solutions is highly competitive. Our clients are not subject to long-term contractual commitments to purchase our solution and can terminate our service and switch to competitors’ offerings on short notice.

We currently compete with large legacy technology vendors that offer on-premise enterprise telephony and contact center systems, such as Avaya Inc., or Avaya, and Cisco Systems, Inc., or Cisco, and legacy on-premise software companies that come from a computer telephony integration, or CTI, heritage, such as Aspect Software, Inc., or Aspect, Genesys Telecommunications Laboratories, Inc., or Genesys, and Interactive Intelligence Group, Inc., or Interactive Intelligence. These companies are supplementing their traditional on-premise contact center systems with cloud offerings, either through acquisition or in-house development. Additionally, we compete with vendors that historically provided other contact center services and technologies and expanded to offer cloud contact center software. These companies include inContact, Inc., or inContact, and LiveOps, Inc., or LiveOps. We also face competition from smaller contact center service providers with specialized contact center software offerings. Our actual and potential competitors may enjoy competitive advantages over us, including greater name recognition, longer operating histories and larger marketing budgets, as well as greater financial or technical resources. With the introduction of new technologies and market entrants, we expect competition to intensify in the future.

Some of our competitors can devote significantly greater resources than we can to the development, promotion and sale of their products and services and many have the ability to initiate or withstand substantial price competition. Current or potential competitors may also be acquired by third parties with significantly greater resources. In addition, many of our competitors have stronger name recognition, longer operating histories, established relationships with clients, more comprehensive product offerings, larger installed bases and major distribution agreements with consultants, system integrators and resellers. Our competitors may also establish cooperative relationships among themselves or with third parties that may further enhance their product offerings or resources. If our competitors’ products, services or technologies become more accepted than our solution, if they are successful in bringing their products or services to market earlier than ours, or if their products or services are less expensive or more technologically capable than ours, then our revenues could be harmed. Pricing pressures and increased competition could result in reduced sales, reduced margins and loss of, or a failure to maintain or improve, our competitive market position, any of which could harm our business.

If we fail to manage our technical operations infrastructure, our existing clients may experience service outages, our new clients may experience delays in the deployment of our solution and we could be subject to, among other things, claims for credits or damages.

Our success depends in large part upon the capacity, stability and performance of our operations infrastructure. From time to time, we have experienced interruptions in service, and may experience such interruptions in the future. For example, on March 20, 2014, we experienced an extended interruption in service due to an issue with third-party equipment that affected our Santa Clara, California colocation facility.

13

Table of Contents

Consistent with prior service interruptions, we anticipate that we will issue client credits and, therefore, revenue for the quarter ending March 31, 2014 will be impacted. While we cannot currently quantify the impact this interruption will have on our revenue, the impact will likely result in our revenue for the quarter ending March 31, 2014 being slightly below our revenue for the quarter ended December 31, 2013. This interruption in service does not impact revenue previously reported for any prior period. These service interruptions may be caused by a variety of factors, including infrastructure changes, human or software errors, viruses, security attacks, fraud, spikes in client usage and denial of service issues. In some instances, we may not be able to identify the cause or causes of these performance problems within an acceptable period of time. Our failure to achieve or maintain expected performance levels, stability and security could harm our relationships with our clients, result in claims for credits or damages, damage our reputation and significantly reduce client demand for our solution and harm our business.

Any future service interruptions could:

We have experienced significant growth in the number of agents and interactions that our infrastructure supports. As our client base grows and their use of our service increases, we will be required to make additional investments in our capacity to maintain adequate stability and performance, the availability of which may be limited or the cost of which may be prohibitive. In addition, we need to properly manage our operations infrastructure in order to support version control, changes in hardware and software parameters and the evolution of our solution. If we do not accurately predict or improve our infrastructure requirements to keep pace with growth in our business, our business could be harmed.

If our Dollar-Based Retention Rate declines, our revenues, gross margins and net income could decrease and we may be required to spend more money to grow our client base and maintain our revenues.

We calculate our Dollar-Based Retention Rate by dividing our Retained Net Invoicing by our Retention Base Net Invoicing on a monthly basis, which we then average using the rates for the trailing twelve months for the period being presented. We define Retention Base Net Invoicing as recurring net invoicing from all clients in the comparable prior year period, and we define Retained Net Invoicing as recurring net invoicing from that same group of clients in the current period. We define recurring net invoicing as subscription and related usage revenue excluding the impact of service credits, reserves and deferrals. Historically, recurring net invoicing has been within 10% of our subscription and related usage revenue. We analyze our Dollar-Based Retention Rate data to gain insight into our ability to retain and grow revenue from our clients and measure the long-term value of our client relationships.

We offer both annual and monthly contracts to our clients, with 30 days’ notice required for changes in the number of agent seats. Our clients can use this notice period to rapidly adjust the number of agent seats used to meet their changing contact center volume needs, including to reduce the number of agent seats to zero. As a general matter, this means that a client can effectively terminate its agreement with us upon 30 days’ notice. As a result, our Dollar-Based Retention Rate could decrease in the future if clients are not satisfied with our service, competition increases from other contact center providers, we experience system outages, alternative technologies emerge, the U.S. or global economy declines or due to many other factors. If our Dollar-Based Retention Rate decreases, we will need to acquire new clients to maintain our existing level of revenues. There can be no assurance that the market for our solution will continue to grow or that we will not lose market share to current or future competitors, either of which would magnify the impact of any decrease in our Dollar-Based Retention Rate. We incur significant costs and expenses, including sales and marketing expenses, to acquire new clients, and those costs and expenses are an important factor in determining our net profitability. Therefore, if we are unsuccessful in maintaining our Dollar-Based Retention Rate or are required to spend significant amounts to acquire new clients, our revenues, gross margins and net income could decrease.

14

Table of Contents

We sell our solution to larger organizations that require longer sales and implementation cycles and often demand more configuration and integration services or customized features and functions that we may not offer, any of which could delay or prevent these sales and harm our growth rates, business and operating results.

As we target our sales efforts at larger organizations, we face greater costs, longer sales and implementation cycles and less predictability in completing our sales. These larger organizations typically require more configuration and integration services, which increases our upfront investment in sales and deployment efforts, with no guarantee that these clients will subscribe to our solution or increase the scope of their subscription. Furthermore, with larger organizations, we must provide greater levels of education regarding the use and benefits of our solution to a broader group of people. As a result of these factors, we must devote a significant amount of sales support and professional services resources to individual clients, thereby increasing the cost and time required to complete sales. Our typical sales cycle for larger organizations is four to five months, but can be significantly longer, and we expect that our average sales cycle may increase as sales to larger organizations continue to grow as a percentage of our business. Longer sales cycles could cause our operating and financial results to be less predictable and to fluctuate from period to period. In addition, many of our clients that are larger organizations initially deploy our solution to support only a portion of their contact center agents. Our success depends on our ability to increase the number of agent seats and the number of applications utilized by larger organizations over time. There is no guarantee that these clients will increase their subscriptions for our solution. If we do not expand our initial relationships with larger organizations, the return on our investments in sales and deployment efforts for these clients will decrease and our business may suffer.

Furthermore, we may not be able to provide the configuration and integration services that larger organizations typically require. For example, our solution does not currently permit clients to add new data fields and functions or modify our code. If prospective clients require customized features or functions that we do not offer, and that would be difficult for them to deploy themselves, then we may lose sales opportunities with larger organizations and our business could suffer.

Because most of our revenue is derived from existing clients, downturns or upturns in new sales will not be immediately reflected in our operating results and may be difficult to discern.

We generally recognize subscription revenue from clients monthly as services are delivered. As a result, most of the subscription revenue we report in each quarter is derived from existing clients. Consequently, a decline in new subscriptions in any single quarter will likely have only a small impact on our revenue results for that quarter. However, the cumulative impact of such declines could harm our revenues in future quarters. Accordingly, the effect of significant downturns in sales and market acceptance of our solution, and potential changes in our pricing policies or renewal rates, will typically not be reflected in our results of operations until future periods. We also may be unable to adjust our cost structure to reflect the changes in revenue, resulting in lower margins and earnings. In addition, our subscription model makes it difficult for us to rapidly increase our revenue through additional sales in any period, as revenue from new clients will be recognized over time as services are delivered. For example, many of our clients initially deploy our solution to support only a portion of their contact center agents. Any increase to our revenue and the value of these existing client relationships will only be reflected in our results of operations as these clients increase the number of agent seats and the number of applications utilized with our solution over time as they experience the benefits of our cloud solution.

We rely on third-party telecommunications and internet service providers to provide our clients and their customers with telecommunication services and connectivity to our cloud contact center software and any failure by these service providers to provide reliable services could subject us to, among other things, claims for credits or damages.

We rely on third-party telecommunication service providers to provide our clients and their customers with telecommunication services. These telephony services include the public switched telephone network, or PSTN, telephone numbers, call termination and origination services, and local number portability for our clients. In addition, we depend on our internet bandwidth suppliers to provide uninterrupted and error-free service through their telecommunications networks. We exercise little control over these third-party providers, which increases our vulnerability to problems with the services they provide. If any of these service providers fail to provide

15

Table of Contents

reliable services, or terminate or increase the cost of the services that we and our clients depend on, we may be required to switch to another service provider. Delays caused by switching our technology to another service provider, if available, and qualifying this new service provider could materially harm our client relationships, business, financial condition and operating results.

Due to our reliance on these service providers, when problems occur, it may be difficult to identify the source of the problem. Service disruption or outages, whether caused by our service, the products or services of our third-party service providers, or our clients’ or their customers’ equipment and systems, may result in loss of market acceptance of our solution and any necessary repairs or other remedial actions may force us to incur significant costs and expenses. Any failure on the part of third-party service providers to achieve or maintain expected performance levels, stability and security could harm our relationships with our clients, result in claims for credits or damages, damage our reputation, significantly reduce client demand for our solution and seriously harm our financial condition and operating results.

We have a history of losses and we may be unable to achieve or sustain profitability.

We have incurred significant losses in each period since our inception in 2001. We incurred net losses of $7.9 million in the year ended December 31, 2011, $19.3 million in the year ended December 31, 2012 and $31.3 million in the year ended December 31, 2013. As of December 31, 2013, we had an accumulated deficit of $90.8 million. These losses and our accumulated deficit reflect the substantial investments we have made to develop our solution and acquire new clients. We expect our costs and expenses to increase in the future due to anticipated increases in cost of revenues, sales and marketing expenses, research and development expenses and general and administrative expenses and, therefore, we expect our losses to continue for the foreseeable future as we continue to make significant future expenditures to develop and expand our business. Furthermore, to the extent we are successful in increasing our client base, we may also incur increased losses because costs associated with acquiring clients are generally incurred up front, while revenues are recognized over the course of the client relationship. Historically, we also have experienced negative gross margins on our professional services, which are expected to continue in the future. In addition, as a public company, we will incur significant legal, accounting and other expenses that we did not incur as a private company. You should not consider our recent growth in revenues as necessarily indicative of our future performance. Accordingly, we cannot assure you that we will achieve profitability in the future nor that, if we do become profitable, we will sustain profitability.

If the market for cloud contact center software solutions develops more slowly than we expect or declines, our business could be harmed.

The cloud contact center software solutions market is not as mature as the market for legacy on-premise contact center systems, and it is uncertain whether cloud contact center solutions will achieve and sustain high levels of client demand and market acceptance. Our success will depend to a substantial extent on the widespread adoption of cloud contact center software solutions as a replacement for legacy on-premise systems. Many larger organizations have invested substantial technical, personnel and financial resources to integrate legacy on-premise contact center systems into their businesses and, therefore, may be reluctant or unwilling to migrate to cloud contact center solutions such as ours. It is difficult to predict client adoption rates and demand for our solution, the future growth rate and size of the cloud contact center software market, or the entry of competitive products and services. The expansion of the cloud contact center software solutions market depends on a number of factors, including the refresh rate for legacy on-premise systems, cost, performance and perceived value associated with cloud contact center software solutions, as well as the ability of providers of cloud contact center software solutions to address security, stability and privacy concerns. If other cloud contact center solution providers experience security incidents, loss of client data, disruptions in delivery or other problems, the market for cloud contact center software products, solutions and services as a whole, including our solution, may be harmed. If cloud contact center software solutions do not achieve widespread adoption, or there is a reduction in demand for such solutions caused by a lack of client acceptance, enhanced product offerings from on-premise providers, technological challenges, weakening economic conditions, security or privacy concerns, competing technologies and products, decreases in corporate spending or otherwise, it could result in decreased revenues and our business could be harmed.

16

Table of Contents

Shifts over time or from quarter-to-quarter in the mix of sizes or types of organizations that purchase our solution or changes in the components of our solution purchased by our clients could harm our operating results.

Our strategy is to sell our solution to both smaller and larger organizations. Our gross margins can vary depending on numerous factors related to the implementation and use of our solution, including the features and number of agent seats purchased by our clients and the level of usage and professional services and support required by our clients. For example, our larger clients typically require more professional services and because our professional services offerings typically have negative margins, any increase in sales of professional services could harm our gross margins and operating results. Sales to larger organizations may also entail longer sales cycles and more significant selling efforts. Selling to smaller clients may involve lower Dollar-Based Retention Rates, smaller contract sizes and greater credit risk and uncertainty. If the mix of organizations that purchase our solution changes, or the mix of solution components purchased by our clients, changes, our revenues and gross margins could decrease and our operating results could be harmed.

We depend on data centers operated by third parties and any disruption in the operation of these facilities could harm our business.

We host our solution at data centers located in Santa Clara, California and Atlanta, Georgia. Any failure or downtime in one of our data center facilities could affect a significant percentage of our clients. While we control and have access to our servers and all of the components of our network that are located in our external data centers, we do not control the operation of these facilities. The owners of our data center facilities have no obligation to renew their agreements with us on commercially reasonable terms, or at all. If we are unable to renew these agreements on commercially reasonable terms, or if one of our data center operators is acquired, closes, suffers financial difficulty or is unable to meet our growing capacity needs, we may be required to transfer our servers and other infrastructure to new data center facilities, and we may incur significant costs and service interruptions in connection with doing so.

Our data centers are subject to various points of failure. Problems with cooling equipment, generators, uninterruptible power supply, routers, switches, or other equipment, whether or not within our control, could result in service interruptions for our clients as well as equipment damage. Our data centers are subject to disasters such as earthquakes, floods, fires, hurricanes, acts of terrorism, sabotage, break-ins, acts of vandalism and other events, which could cause service interruptions or the operators of these data centers to close their facilities for an extended period of time or permanently. The destruction or impairment of any of our data center facilities could result in significant downtime for our solution and the loss of client data. Because our ability to attract and retain clients depends on our providing clients with highly reliable service, even minor interruptions in our service could harm our business, revenues and reputation. Additionally, in connection with the continuing expansion of our existing data center facilities, there is an increased risk that service interruptions may occur as a result of server addition, relocation or other issues.

In addition, our data centers are subject to increased costs of power. We may not be able to pass on any increase in costs of energy to our clients, which could reduce our operating margins.

Our limited operating history makes it difficult to evaluate and predict our current business and future prospects.

We have been in existence since 2001, and much of our growth has occurred in recent periods. Our limited operating history and recent growth may make it difficult for you to evaluate our current business and our future prospects. We have encountered and will continue to encounter risks and difficulties frequently experienced by growing companies in rapidly changing industries, including increasing and unforeseen expenses as we continue to grow our business.

Our ability to forecast our future operating results is limited and subject to a number of uncertainties, including our ability to plan for and model future growth. We have encountered and will continue to encounter risks and uncertainties frequently experienced by growing companies in rapidly changing industries, such as the risks and uncertainties described herein. If our assumptions regarding these risks and uncertainties, which we use to plan our business, are incorrect or change due to adjustments in our markets, or if we do not address these

17

Table of Contents

risks successfully, our operating and financial results could differ materially from our expectations and our business could suffer.

If our solution fails to perform properly or if it contains technical defects, our reputation could be harmed, our market share may decline and we could be subject to product liability claims.

Our solution may contain undetected errors or defects that may result in failures or otherwise cause our solution to fail to perform in accordance with client expectations. Because our clients use our solution for mission-critical aspects of their business, any errors or defects in, or other performance problems with, our solution may damage our clients’ businesses and could significantly harm our reputation. If that occurs, we could lose future sales, or our existing clients could elect to cancel or not renew our solution, seek payment credits or delay or withhold payment to us, which could result in reduced revenues, an increase in our provision for uncollectible accounts and service credits and an increase in collection cycles for accounts receivable. Clients also may make indemnification or warranty claims against us, which could result in significant expense and risk of litigation. Product performance problems could result in loss of market share, failure to achieve market acceptance and the diversion of development resources.

Any product liability, intellectual property, warranty or other claims against us could damage our reputation and relationships with our clients, and could require us to spend significant time and money in litigation or pay significant settlements or damages. Although we maintain general liability insurance, including coverage for errors and omissions, this coverage may not be sufficient to cover liabilities resulting from such claims. Also, our insurer may disclaim coverage. Our liability insurance also may not continue to be available to us on reasonable terms, in sufficient amounts, or at all. Any contract or product liability claims successfully brought against us would harm our business.

If our security measures are breached or unauthorized access to client data is otherwise obtained, our solution may be perceived as not being secure, clients may reduce the use of or stop using our solution and we may incur significant liabilities.

Our solution involves the storage and transmission of our clients’ information, including information about our clients’ customers or other information treated by our clients as confidential. Unauthorized access or other breaches in our security could result in the loss of confidentiality, integrity and availability of information, leading to litigation, indemnity obligations and other liability. While we have security measures in place to protect client information and minimize the probability of security breaches, if these measures fail as a result of third-party action, employee error, malfeasance or otherwise, and someone obtains unauthorized access to our clients’ data, our reputation could be damaged, our business may suffer and we could incur significant liability. Because the techniques used to obtain unauthorized access or sabotage systems change frequently and generally are not identified until they are launched against a target, we may be unable to anticipate these techniques or to implement adequate preventative measures. In addition, any failure on the part of third parties, including our clients, to achieve or maintain security measures for their own systems could harm our relationships with our clients, result in claims against us for credits or damages, damage our reputation and significantly reduce client demand for our solution. Any or all of these issues could harm our ability to attract new clients, cause existing clients to elect not to renew their subscriptions, result in reputational damage or subject us to third-party lawsuits, regulatory fines or other action or liability, all of which could harm our operating results.

The contact center software solutions market is subject to rapid technological change, and we must develop and sell incremental and new products in order to maintain and grow our business.

The contact center software solutions market is characterized by rapid changes in client requirements, frequent introductions of new and enhanced products and continuing and rapid technological advancement. To compete successfully, we must continue to design, develop, manufacture and sell new and enhanced contact center products, applications and features that provide increasingly higher capabilities, performance and stability at lower cost. If we are unable to develop new features for our existing solution or new applications that achieve market acceptance or that keep pace with technological developments, our business would be harmed. For example, we are focused on enhancing the reliability, features and functionality of our contact center solution to enhance its utility to our clients, particularly larger clients with complex, dynamic and global operations. The

18

Table of Contents

success of these enhancements depends on many factors, including timely development, introduction and market acceptance, as well as our ability to transition our existing clients to these new products, applications and features. Failure in this regard may significantly impair our revenue growth. In addition, because our solution is designed to operate on a variety of systems, we will need to continuously modify and enhance our solution to keep pace with changes in hardware, operating systems, the increasing trend toward multi-channel communications and other changes to software technologies. We may not be successful developing these modifications and enhancements or bringing them to market in a timely fashion. Furthermore, uncertainties about the timing and nature of new network platforms or technologies, or modifications to existing platforms or technologies, could delay introduction of our solution and increase our research and development expenses. Any failure of our solution to operate effectively with future network platforms and technologies could reduce the demand for our solution, result in client dissatisfaction and harm our business.

Our ability to continue to enhance our solution is dependent on adequate research and development resources. If we are not able to adequately fund our research and development efforts, we may not be able to compete effectively and our business and operating results may be harmed.

In order to remain competitive, we must continue to develop new solution offerings and enhancements to our existing cloud contact center software. Maintaining adequate research and development personnel and resources to meet the demands of the market is essential. If we are unable to develop products, applications or features internally due to certain constraints, such as high employee turnover, inability to hire sufficient research and development personnel or a lack of other research and development resources, we may miss market opportunities. Furthermore, many of our competitors expend a considerably greater amount of funds on their research and development programs, and those that do not may be acquired by larger companies that would allocate greater resources to our competitors’ research and development programs. Our failure to devote adequate research and development resources or compete effectively with the research and development programs of our competitors could harm our business.

Our growth depends in part on the success of our strategic relationships with third parties and our failure to successfully grow and manage these relationships could harm our business.

We leverage strategic relationships with third parties, such as CRM, system integrator, technology and telephony providers. For example, our CRM and system integrator relationships provide significant lead generation for new client opportunities. As we grow our business, we will continue to depend on both existing and new strategic relationships. Our competitors may be more successful than we are in establishing relationships with third parties or may provide incentives to third parties to favor their products over our solution. Furthermore, if our partners are acquired, they may no longer support or promote our solution, or may be less effective in doing so, which could harm our business, financial condition and operations. If we are unsuccessful in establishing or maintaining our strategic relationships with third parties, our ability to compete in the marketplace or to grow our revenues could be impaired and our operating results may suffer. Even if we are successful, we cannot assure you that these relationships will result in increased client usage of our solution or increased revenue.

In addition, identifying new partners, and negotiating and documenting relationships with them, requires significant time and resources. As the complexity of our solution and our third-party relationships increases, the management of those relationships and the negotiation of contractual terms sufficient to protect our rights and limit our potential liabilities will become more complicated. We also license technology from certain third-party partners. Certain of these license agreements permit either party to terminate all or a portion of the license without cause at any time. Our inability to successfully manage these complex relationships or negotiate sufficient contractual terms could harm our business.

If we are unable to maintain the compatibility of our software with other products and technologies, our business would be harmed.

Our clients often integrate our solution with their business applications, particularly third-party CRM solutions. These third-party providers or their partners could alter their products so that our solution no longer integrates well with them, or they could delay or deny our access to technology releases that allow us to adapt our

19

Table of Contents

solution to integrate with their products in a timely fashion. If we cannot adapt our solution to changes in complementary technology deployed by our clients, it may significantly impair our ability to compete effectively.

We are subject to many hazards and operational risks that can disrupt our business, some of which may not be insured or fully covered by insurance.

Our operations are subject to many hazards inherent in the cloud contact center software business, including:

These risks could result in substantial losses and the curtailment or suspension of our operations. For example, in the event of a major earthquake along the west coast (where our corporate headquarters and one of our data centers are located), hurricane or tropical storm in the southeastern United States (where our other data center is located) or catastrophic events such as fire, power loss, telecommunications failure, cyber-attack, war or terrorist attack, we may be unable to continue our operations and may endure system and service interruptions, reputational harm, delays in product development, breaches of data security and loss of critical data, all of which could harm our operating results.

We are not insured against all claims, events or accidents that might occur. If a significant accident or event occurs that is not fully insured, if we fail to recover all anticipated insurance proceeds for significant accidents or events for which we are insured, or if we or our data center providers fail to reopen facilities damaged by such accidents or events, our operations and financial condition could be harmed. In addition to being denied coverage under existing insurance policies, we may not be able to maintain or obtain insurance of the type and amount we desire at reasonable rates.

Our business could be harmed if our clients are not satisfied with the professional services and technical support provided by us or our partners.

Our business depends on our ability to satisfy our clients, not only with respect to our solution but also with the professional services and technical support that are performed to enable our clients to implement and use our solution to address their business needs. Professional services and technical support may be performed by our own staff or, with respect to a select subset of our solution, by third parties. We may be unable to respond quickly enough to accommodate short-term increases in client demand for support services. We also may be unable to modify the format of our support services to compete with changes in support services provided by our competitors. Increased client demand for these services, without corresponding revenues, could increase costs and harm our operating results. If a client is not satisfied with the deployment and ongoing services performed by us or a third party, then we could lose clients, miss opportunities to expand our business with these clients, incur additional costs, or lose, or suffer reduced margins on, our service revenue, any of which could damage our ability to grow our business. In addition, negative publicity related to our professional services and technical support, regardless of its accuracy, may further damage our business by affecting our ability to compete for new business with current and prospective clients.

The loss of one or more of our key clients, or a failure to renew our subscription agreements with one or more of our key clients, could harm our ability to market our solution.

We rely on our reputation and recommendations from key clients in order to market and sell our solution. The loss of any of our key clients, or a failure of some of them to renew or to continue to recommend our solution, could have a significant impact on our revenues, reputation and our ability to obtain new clients. In addition, acquisitions of our clients could lead to cancellation of our contracts with those clients or by the acquiring companies, thereby reducing the number of our existing and potential clients.

20

Table of Contents

Our clients may fail to pay us in accordance with the terms of their agreements, necessitating action by us to collect payment, or may terminate their subscriptions for our solution.

If clients fail to pay us under the terms of our agreements, fail to comply with the terms of our agreements, or terminate their subscriptions for our solution, we may lose revenue, be unable to collect amounts due to us, be subject to legal or regulatory action and incur costs in enforcing the terms of our contracts, including litigation. These risks increase the longer the term of our client arrangements. Some of our clients may seek bankruptcy protection or other similar relief and fail to pay amounts due to us, or pay those amounts more slowly, either of which could harm our operating results, financial position and cash flow.

Sales to clients outside the United States or with international operations and our international sales efforts and operations support expose us to risks inherent in international sales and operations.

A key element of our growth strategy is to expand our international sales efforts and develop a worldwide client base. Because of our limited experience with international sales efforts, our international expansion may not be successful and may not produce the return on investment we expect. To date, we have realized only a small portion of our revenues from clients outside the United States.

We currently have full-time employees in the Philippines, who provide technical support, training and other professional services, as well as in Russia, who provide software development services. Operating in international markets requires significant resources and management attention and subjects us to intellectual property, regulatory, economic and political risks that are different from those in the United States. As we increase our international sales efforts and continue our other international operations, we will face risks in doing business internationally that could harm our business, including:

21

Table of Contents

The occurrence of any of these risks could harm our international operations, increase our operating costs and hinder our ability to grow our international business and, consequently, our overall business and results of operations.

In addition, compliance with laws and regulations applicable to our international operations increases our cost of doing business outside the United States. We may be unable to keep current with changes in foreign government requirements and laws as they change from time to time. Failure to comply with these regulations could harm our business. In many countries outside the United States it is common for others to engage in business practices that are prohibited by our internal policies and procedures or U.S. regulations applicable to us. Although we have implemented policies and procedures designed to ensure compliance with these laws and policies, there can be no assurance that all of our employees, contractors, strategic partners and agents will comply with these laws and policies. Violations of laws or key control policies by our employees, contractors, strategic partners or agents could result in delays in revenue recognition, financial reporting misstatements, fines, penalties, or prohibitions on selling our solution and could harm our business.

We depend on our senior management team and the loss of one or more key employees or an inability to attract and retain highly skilled employees could harm our business.

Our success largely depends upon the continued services of our key executive officers. We also rely on our leadership team in the areas of research and development, marketing, sales, services and general and administrative functions, and on mission-critical individual contributors. From time to time, there may be changes in our executive management team resulting from the hiring or departure of executives, which could disrupt our business. The loss of one or more of our executive officers or key employees could seriously harm our business. We currently do not maintain key person life insurance policies on any of our employees.

To execute our growth plan, we must attract and retain highly qualified personnel. Competition for these personnel is intense, especially for engineers with high levels of experience in designing and developing cloud software and for senior sales executives. We have, from time to time, experienced, and we expect to continue to experience, difficulty in hiring and retaining employees with appropriate qualifications. Many of the companies with which we compete for experienced personnel have greater resources than we have. If we hire employees from competitors or other companies, their former employers may attempt to assert that these employees or we have breached legal obligations, resulting in a diversion of our time and resources and, potentially, damages. In addition, job candidates and existing employees, particularly in the San Francisco Bay Area, often consider the value of the stock awards they receive in connection with their employment. If the perceived value of our stock awards declines, either because we are a public company or otherwise, it may harm our ability to recruit and retain highly skilled employees. In addition, we invest significant time and expense in training our employees, which increases their value to competitors who may seek to recruit them. If we fail to attract new personnel or fail to retain and motivate our current personnel, our business and future growth prospects would be harmed.

Failure to adequately expand our sales force will impede our growth.

We will need to continue to expand and optimize our sales infrastructure in order to grow our client base and our business. We plan to aggressively expand our sales force, both domestically and internationally. Identifying and recruiting qualified personnel and training them in the use of our solution requires significant time, expense and attention. It can take several months before our sales representatives are fully trained and productive. Our business may be harmed if our efforts to expand and train our sales force do not generate a corresponding increase in revenues. In particular, if we are unable to hire, develop and retain talented sales personnel or if new sales personnel are unable to achieve desired productivity levels in a reasonable period of time, we may not be able to realize the expected benefits of this investment or increase our revenues.

22

Table of Contents

If we fail to grow our marketing capabilities and develop widespread brand awareness cost effectively, our business may suffer.

Our ability to increase our client base and achieve broader market acceptance of our cloud contact center software solution will depend to a significant extent on our ability to expand our marketing operations. We plan to dedicate significant resources to our marketing programs, including internet advertising, digital marketing campaigns, social marketing, trade shows, industry events, co-marketing with strategic partners and telemarketing. The effectiveness of our online advertising has varied over time and may vary in the future due to competition for key search terms, changes in search engine use and changes in the search algorithms used by major search engines. All of these efforts will continue to require us to invest significant financial and other resources in our marketing efforts. Our business will be seriously harmed if our efforts and expenditures do not generate a proportionate increase in revenue.

In addition, we believe that developing and maintaining widespread awareness of our brand in a cost-effective manner, both in the United States and internationally, is critical to achieving widespread acceptance of our solution and attracting new clients. Brand promotion activities may not generate client awareness or increase revenues, and even if they do, any increase in revenues may not offset the costs and expenses we incur in building our brand. If we fail to successfully promote, maintain and protect our brand, or incur substantial costs and expenses, we may fail to attract or retain clients necessary to realize a sufficient return on our brand-building efforts, or to achieve the widespread brand awareness that is critical for broad client adoption of our solution.

We may not be able to secure additional financing on favorable terms, or at all, to meet our future capital needs.

To date, we have financed our operations, primarily through sales of our solution, net proceeds from the issuance of our convertible preferred stock, lease facilities and, more recently, debt financing. We do not know when or if our operations will generate sufficient cash to fund our ongoing operations. In the future, we may require additional capital to respond to business opportunities, challenges, acquisitions, a decline in sales, increased regulatory obligations or unforeseen circumstances and may engage in equity or debt financings or enter into credit facilities.

We have a substantial amount of debt. As of December 31, 2013, we had $17.5 million outstanding under the loan and security agreement governing our revolving line of credit and term loan and $3.7 million outstanding under a promissory note with the Universal Services Administration Company. In February 2014, we entered into a loan and security agreement for a term loan of up to $30.0 million. At closing, we borrowed $19.6 million of the term loan net of $0.4 million in debt costs, with the remaining $10.0 million available to be borrowed until February 2015. Our loan and security agreements are collateralized by substantially all of our assets and contain a number of covenants that limit our ability to, among other things, sell assets, make acquisitions or investments, incur debt, grant liens, pay dividends, enter into transactions with our affiliates and use all of our available cash on hand and may prevent us from engaging in acts that may be in our best long-term interests. The existing collateral pledged under the loan and security agreements and the covenants to which we are bound may prevent us from being able to timely secure additional debt or equity financing on favorable terms, or at all, or to pursue business opportunities, including potential acquisitions. Any debt financing obtained by us in the future would cause us to incur additional debt service expenses and could include 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 pursue business opportunities. If we raise additional funds through further issuances of equity or convertible debt securities, our existing stockholders could suffer significant dilution in their percentage ownership of our company, and any new equity securities we issue could have rights, preferences and privileges senior to those of holders of our common stock. If we are unable to obtain adequate financing or financing on terms satisfactory to us when we require it, our ability to continue to grow and support our business and to respond to business challenges could be significantly limited.

Adverse economic conditions may harm our business.

Our business depends on the overall demand for cloud contact center software solutions and on the economic health of our current and prospective clients. The recent financial recession resulted in a significant weakening of the economy in the United States and globally, more limited availability of credit, a reduction in business confidence and activity, and other difficulties that affected the industries to which we sell our solution. We plan to market and sell our solution in Europe, Asia and other international markets. If economic conditions

23

Table of Contents

in the United States, Europe and Asia and other key potential markets for our solution continue to remain uncertain or deteriorate further, many clients may delay or reduce their contact center and overall information technology spending. If our clients continue to experience economic hardship, this could reduce the overall demand for our solution, delay and lengthen sales cycles and lead to slower growth or even a decline in our revenues, net income and cash flows.

The forecasts of market growth included in this prospectus may prove to be inaccurate, and even if the markets in which we compete achieve the forecasted growth, our business may not grow at similar rates, if at all.

Growth forecasts are subject to significant uncertainty and are based on assumptions and estimates that may not prove to be accurate. The forecasts in this prospectus relating to the expected growth in contact centers and contact centers as a service may prove to be inaccurate.

Even if these markets experience the forecasted growth described in this prospectus, we may not grow our business at similar rates, or at all. Our growth is subject to many factors, including whether the market for cloud contact center software solutions continues to grow, the rate of market acceptance of our solution versus those of our competitors and our success in implementing our business strategies, each of which is subject to many risks and uncertainties. Accordingly, the forecasts of market growth included in this prospectus should not be taken as indicative of our future growth.

We may acquire other companies or technologies, which could divert our management’s attention, result in additional dilution to our stockholders and otherwise disrupt our operations and harm our operating results.

We may in the future seek to acquire or invest in businesses, applications or technologies that we believe could complement or expand our solution, enhance our technical capabilities or otherwise offer growth opportunities. The pursuit of potential acquisitions may divert the attention of management and cause us to incur various costs and expenses in identifying, investigating and pursuing suitable acquisitions, whether or not they are consummated. We may not be able to identify desirable acquisition targets or be successful in entering into an agreement with any particular target.

To date, the growth in our business has been primarily organic, and we have limited experience in acquiring other businesses, having only completed one small acquisition. In October 2013, we acquired Face It, Corp., which we refer to as SoCoCare, a social engagement and mobile customer care solution provider. In any acquisitions, including SoCoCare, we may not be able to successfully integrate acquired personnel, operations and technologies, or effectively manage the combined business following the acquisition. We also may not achieve the anticipated benefits from our acquisition of SoCoCare or future acquired businesses due to a number of factors, including:

In addition, a significant portion of the purchase price of companies we acquire may be allocated to acquired goodwill and other intangible assets, which must be assessed for impairment at least annually. In the future, if

24

Table of Contents

our acquisitions do not yield expected returns, we may be required to take charges to our operating results based on this impairment assessment process, which could harm our results of operations.

Acquisitions could also result in dilutive issuances of equity securities, the use of our available cash, or the incurrence of debt, which could harm our operating results. In addition, if an acquired business fails to meet our expectations, our operating results, business and financial condition may suffer.

If we are unable to implement and maintain effective internal control over financial reporting in the future, investors may lose confidence in the accuracy and completeness of our financial reports and the market price of our common stock may decrease.

As a public company, we will be required to maintain internal control over financial reporting and to report any material weaknesses in such internal controls. Section 404 of the Sarbanes-Oxley Act of 2002, or the Sarbanes-Oxley Act, requires that we evaluate and determine the effectiveness of our internal control over financial reporting and, beginning with our annual report for the year ending December 31, 2015, provide a management report on our internal control over financial reporting, which must be attested to by our independent registered public accounting firm to the extent we are no longer an “emerging growth company,” as defined by The Jumpstart Our Businesses Act of 2012, or the JOBS Act. Two material weaknesses were identified in our internal control over financial reporting in 2010, one of which was remediated in 2011 and the other of which was remediated in 2012. A “material weakness” is a deficiency, or a combination of deficiencies, in internal control over financial reporting such that there is a reasonable possibility that a material misstatement of our annual or interim financial statements will not be prevented or detected on a timely basis.

If in the future we have material weaknesses in our internal control over financial reporting, we may not detect errors on a timely basis and our financial statements may be materially misstated. We are in the process of designing and implementing our internal control over financial reporting, which process will be time consuming, costly and complicated. If we identify material weaknesses in our internal control over financial reporting, if we are unable to comply with the requirements of Section 404 in a timely manner, 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 attest that our internal control over financial reporting is effective, investors may lose confidence in the accuracy and completeness of our financial reports and the market price of our common stock could decrease. We could also become subject to stockholder or other third-party litigation as well as investigations by the stock exchange on which our securities are listed, the Securities and Exchange Commission, or SEC, or other regulatory authorities, which could require additional financial and management resources and could result in fines, trading suspensions or other remedies.

Changes in financial accounting standards or practices may cause adverse, unexpected financial reporting fluctuations and affect our reported operating results.

Generally accepted accounting principles in the United States are subject to interpretation by the Financial Accounting Standards Board, or FASB, the SEC and various bodies formed to promulgate and interpret appropriate accounting principles. A change in accounting standards or practices can have a significant effect on our reported results and may even affect our financial statements completed before the change is effective. New accounting pronouncements and varying interpretations of accounting pronouncements have occurred and will occur in the future. Changes to existing rules or the questioning of current practices may harm our reported financial results or the way we account for or conduct our business.

For example, we recognize subscription revenue in accordance with Accounting Standards Update 2009-13, Revenue Recognition (Topic 605) — Multiple-Deliverable Revenue Arrangements — a Consensus of the Emerging Issues Task Force (“ASU 2009-13”) (formerly known as EITF 08-01). The FASB and the SEC may issue interpretations and guidance for applying the relevant accounting standards to a wide range of sales contract terms and business arrangements that are prevalent in revenue recognition arrangements. As a result of future interpretations or applications of existing accounting standards, including ASU 2009-13, we could be required to delay revenue recognition into future periods, which would harm our operating results.

In addition, certain factors have in the past and may in the future cause us to defer recognition of subscription revenues. For example, the inclusion in our client contracts of material non-standard terms, such as

25

Table of Contents

acceptance criteria, could require the deferral of subscription revenue. To the extent that such contracts become more prevalent in the future our revenue may be harmed.

Because of these factors and other specific requirements under accounting principles generally accepted in the United States for revenue recognition, we must have very precise terms in our arrangements in order to recognize revenue when we deliver our solution or perform our professional services. Negotiation of mutually acceptable terms and conditions can extend our sales cycle, and we may accept terms and conditions that do not permit revenue recognition at the time of delivery.

We may not be able to utilize a significant portion of our net operating loss or research tax credit carryforwards, which could harm our profitability.

As of December 31, 2013, we had federal and state net operating loss carryforwards due to prior period losses of $68.4 million and $35.8 million, respectively, which if not utilized will begin to expire in 2024 for federal purposes and 2014 for state purposes. We also have federal research tax credit carryforwards, which if not utilized will begin to expire in 2024. If we are unable to generate sufficient taxable income to utilize our net operating loss and research tax credit carryforwards, these carryforwards could expire unused and be unavailable to offset future income tax liabilities, which could harm our profitability.

In addition, under Section 382 of the Internal Revenue Code of 1986, as amended, or the Code, our ability to utilize net operating loss carryforwards or other tax attributes, such as research tax credits, in any taxable year may be limited if we experience an “ownership change.” A Section 382 “ownership change” generally occurs if one or more stockholders or groups of stockholders who own at least 5% of our stock increase their ownership by more than 50 percentage points over their lowest ownership percentage within a rolling three-year period. Similar rules may apply under state tax laws. This offering or future issuances or sales of our stock (including certain transactions involving our stock that are outside of our control) could cause an “ownership change.” If an “ownership change” occurs, Section 382 would impose an annual limit on the amount of pre-ownership change net operating loss carryforwards and other tax attributes we can use to reduce our taxable income, potentially increasing and accelerating our liability for income taxes, and also potentially causing those tax attributes to expire unused. It is possible that such an ownership change could materially reduce our ability to use our net operating loss carryforwards or other tax attributes to offset taxable income, which could harm our profitability.

Risks Related to Our Intellectual Property

Any failure to protect our intellectual property rights could impair our ability to protect our proprietary technology and our brand.

Our success and ability to compete depend in part upon our intellectual property. We currently have three registered and five pending trademarks and four issued U.S. patents and seventeen pending patent applications. We primarily rely on copyright, trade secret and trademark laws, trade secret protection and confidentiality or license agreements with our employees, clients, partners and others to protect our intellectual property rights. However, the steps we take to protect our intellectual property rights may be inadequate. We may not be able to obtain any further patents or trademarks, and our pending applications may not result in the issuance of patents or trademarks. We have pending patent applications and limited trademark registrations outside the U.S., and we may have to expend significant resources to obtain additional protection as we expand our international operations. Furthermore, legal standards relating to the validity, enforceability and scope of protection of intellectual property rights in other countries, including Russia, where we have significant research and development operations, are uncertain and may afford little or no effective protection of our proprietary technology. Consequently, we may be unable to prevent our proprietary technology from being exploited abroad, which could affect our ability to expand to international markets or require costly efforts to protect our technology.

In order to protect our intellectual property rights, we may be required to spend significant resources to monitor and protect these rights. Litigation brought to protect and enforce our intellectual property rights could be costly, time consuming and distracting to management and could result in the impairment or loss of portions of our intellectual property. Furthermore, our efforts to enforce our intellectual property rights may be met with

26

Table of Contents

defenses, counterclaims and countersuits attacking the validity and enforceability of our intellectual property rights. Accordingly, we may not be able to prevent third parties from infringing upon or misappropriating our intellectual property. Our failure to secure, protect and enforce our intellectual property rights could substantially harm the value of our technology, solutions, brand and business.

We may continue to be subject to third-party intellectual property infringement claims.

There is considerable patent and other intellectual property development activity and litigation in our industry. Our success depends upon our not infringing upon the intellectual property rights of others. Our competitors, as well as a number of other entities and individuals, may own or claim to own intellectual property relating to our industry. From time to time, third parties have claimed that we are infringing upon their intellectual property rights. For example, on April 3, 2012, NobelBiz, Inc. filed a patent infringement lawsuit against us alleging that our local caller ID management service infringes United States Patent No. 8,135,122. Subsequently, NobelBiz amended its complaint to add claims related to U.S. Patent No. 8,565,399, which is a continuation in the same family as the prior patent and addresses the same technology. NobelBiz seeks damages in the form of lost profits as well as injunctive relief. See “Business — Legal Proceedings.” If NobelBiz is successful in its request for injunctive relief, we will have to stop providing the accused technology, enter into a license agreement with NobelBiz for the technology or modify our technology, any of which could harm our business. There can be no assurance that we (i) will prevail in this action, (ii) can develop non-infringing technology that is accepted in the market if we are enjoined from using the accused technology or (iii) will be able to negotiate favorable licensing terms with NobelBiz. There can also be no assurance that other actions alleging infringement by us of third-party patents will not be asserted or prosecuted against us.

Certain technology necessary for us to provide our solution may be patented by other parties either now or in the future. If such technology were held under patent by another person, we would have to negotiate a license for the use of that technology. We may not be able to negotiate such a license at a price that is acceptable, or at all. The existence of such a patent, or our inability to negotiate a license for any such technology on acceptable terms, could force us to cease using such technology and offering solutions incorporating such technology.

In the future, others may claim that our solution and underlying technology infringe or violate their intellectual property rights. However, we may be unaware of the intellectual property rights that others may claim cover some or all of our technology or solution. Any claims or litigation could cause us to incur significant costs and expenses and, if successfully asserted against us, could require that we pay substantial damages or ongoing royalty payments, require that we refrain from using, manufacturing or selling certain offerings or using certain processes, prevent us from offering our solution, or require that we comply with other unfavorable terms, any of which could harm our business and operating results. We may also be obligated to indemnify our clients or business partners or pay substantial settlement costs, including royalty payments, in connection with any such claim or litigation and to obtain licenses, modify applications, or refund fees, which could be costly. Even if we were to prevail in such a dispute, any litigation regarding our intellectual property could be costly and time consuming and divert the attention of our management and key personnel from our business operations.

We employ third-party licensed software for use in or with our solution, and the inability to maintain these licenses or errors in the software we license could result in increased costs, or reduced service levels, which could harm our business.

Our solution incorporates certain third-party software obtained under licenses from other companies. We anticipate that we will continue to rely on such third-party software and development tools from third parties in the future. Although we believe that there are commercially reasonable alternatives to the third-party software we currently license, this may not always be the case, or it may be difficult or costly to transition to other providers. In addition, integration of the software used in our solution with new third-party software may require significant work and require substantial investment of our time and resources. To the extent that our solution depends upon the successful operation of third-party software in conjunction with our software, any undetected errors or defects in this third-party software could prevent the deployment or impair the functionality of our solution, delay new product or solution introductions, result in a failure of our solution and injure our reputation. Our use of additional or alternative third-party software would require us to enter into license agreements with third parties.

27

Table of Contents

There can be no assurance that the technology licensed by us will continue to provide competitive features and functionality or that licenses for technology currently utilized by us or other technology which we may seek to license in the future, will be available to us on commercially reasonable terms or at all. The loss of, or inability to maintain, existing licenses could result in implementation delays or reductions until equivalent technology or suitable alternative solutions could be developed, identified, licensed and integrated, and could harm our business.

Our solution utilizes open source software, and any failure to comply with the terms of one or more of these open source licenses could negatively affect our business.

Our solution includes software covered by open source licenses, which may include, for example, free general public use licenses, open source front-end libraries, open source stand-alone applications and open source applications. The terms of various open source licenses have not been interpreted by United States courts, and there is a risk that such licenses could be construed in a manner that imposes unanticipated conditions or restrictions on our ability to market our solution. By the terms of certain open source licenses, we could be required to release the source code of our proprietary software, and to make our proprietary software available under open source licenses, if we combine our proprietary software with open source software in a certain manner. In the event that portions of our proprietary software are determined to be subject to an open source license, we could be required to publicly release the affected portions of our source code, re-engineer all or a portion of our technologies, or otherwise be limited in the licensing of our technologies, each of which could reduce or eliminate the value of our technologies and solutions. In addition to risks related to license requirements, usage of open source software can lead to greater risks than use of third-party commercial software, as open source licensors generally do not provide warranties or controls on the origin of the software. Given the nature of open source software, there is also a risk that third parties may assert copyright and other intellectual property infringement claims against us based on our use of certain open source software programs. Many of the risks associated with the usage of open source software cannot be eliminated, and could harm our business.

Risks Related to Regulatory Matters

Failure to comply with laws and regulations could harm our business.

Our business is subject to regulation by various federal, state, local and foreign governmental agencies, including agencies responsible for monitoring and enforcing employment and labor laws, workplace safety, environmental laws, consumer protection laws, anti-bribery laws, import/export controls, federal securities laws and tax laws and regulations. In certain jurisdictions, these regulatory requirements may be more stringent than those in the United States and in other circumstances these requirements may be more stringent in the United States. Noncompliance with applicable regulations or requirements could subject us to investigations, sanctions, mandatory recalls, enforcement actions, disgorgement of profits, fines, damages, civil and criminal penalties or injunctions. If any governmental sanctions, fines or penalties are imposed, or if we do not prevail in any possible civil or criminal litigation, our business, operating results and financial condition could be harmed. In addition, responding to any action will likely result in a significant diversion of management’s attention and resources and an increase in professional fees. Enforcement actions and sanctions could further harm our business, operating results and financial condition.

Increased taxes on our service may increase our clients’ cost of using our service and/or reduce our profit margins to the extent the costs are not passed through to our clients, and we may be subject to liabilities for past sales and other taxes, surcharges and fees.

Prior to 2012, we did not collect or remit state or local sales, use, gross receipts, excise and utility user taxes, fees or surcharges on our solution.

During 2011, we analyzed our activities and determined that we were obligated to collect sales taxes on sales of our subscriptions in certain states. Accordingly, we registered with those states, paid past-due amounts and began collecting sales taxes from our clients and remitting such taxes to the applicable state taxing authorities. During 2013, we analyzed our activities and determined that we may be obligated to collect and remit sales, excise and utility user taxes, as well as surcharges as a communications service provider, and pay gross

28

Table of Contents

receipts taxes, on our usage-based fees in certain states and municipalities. We have neither collected nor remitted state and local taxes or surcharges on usage-based fees in any of the periods presented.

Based on our ongoing assessment, we will register for tax and regulatory purposes in states where we determine such regulations apply to our activities and commence collecting and remitting state and local taxes and surcharges on applicable usage-based fees. We have accrued a contingent liability for our best estimate of the probable amount of taxes and surcharges that may be imposed by various states and municipalities on our activities prior to registration. This contingent liability is based on our analysis of a number of factors, including the source location of our usage-based fees and the rules and regulations in each state. The actual amount of state and local taxes and surcharges paid may differ from our estimates. See Note 10 to the notes to our consolidated financial statements.

While we have accrued for these potential liabilities in each period, such accruals are based on analyses of our business activities, the operation of our solution, applicable statutes, regulations and rules in each state and locality and estimates of revenue subject to sales tax or other charge. State and local taxing and regulatory authorities may challenge our position and may decide to audit our business and operations with respect to state or local sales, use, gross receipts, excise and utility user taxes, fees or surcharges, which could result in tax liabilities, fees or surcharges for us above our recorded accrued liability or additional tax liabilities, fees or surcharges for our clients, which could harm our results of operations and our relationships with our clients. In addition, state or local taxing and regulatory authorities may assess penalties and interest related to our tax and regulatory obligations.

The applicability of state or local taxes, fees or surcharges relative to services such as ours is complex, ambiguous and subject to interpretation and change. If states enact new legislation or if taxing and regulatory authorities promulgate new rules or regulations or expand their interpretations of existing rules and regulations, we could incur additional liabilities. In addition, the collection of additional taxes, fees or surcharges in the future could increase our prices or reduce our profit margins. Compliance with new or existing legislation, rules or regulations may also make us less competitive with those competitors who are not subject to, or choose not to comply with, such legislation, rules or regulations. We have incurred, and will continue to incur, substantial ongoing costs associated with complying with state or local tax, fee or surcharge requirements in the numerous markets in which we conduct or will conduct business.

We are subject to assessments for unpaid Universal Service Fund contributions, as well as interest thereon and potential penalties, due to our late registration and reporting of revenues.

During the third quarter of 2012, we determined that based on our business activities, we are classified as a telecommunications service provider for regulatory purposes and we are required to make direct contributions to the federal Universal Service Fund and related funds, or USF, based on revenue we receive from the resale of interstate and international telecommunications services. Previously, we had been advised that our telecommunications services were an integral part of an information service and accordingly made indirect USF contributions as an end user through payments to our wholesale telecommunications service providers. In order to comply with the obligation to make direct contributions, in November 2012, we made a voluntary self-disclosure to the Federal Communications Commission, or FCC, Enforcement Bureau and have registered with the Universal Service Administrative Company, or USAC, which is charged by the FCC with administering the USF. As of December 31, 2013, we had a promissory note issued to USAC of $3.7 million and accrued liabilities for unpaid USF contributions of $4.2 million, which are included in accrued federal fees in the consolidated balance sheet. Approximately $803,000 of these amounts pertains to periods prior to 2008. In April 2013, we began remitting required contributions on a prospective basis directly to USAC.

Our registration with USAC subjects us to assessments for unpaid USF contributions, as well as interest and penalties thereon, due to our late registration and reporting of revenues. We are required to pay assessments for periods prior to our registration. While we are in discussions with the FCC to limit such back assessments to the period 2008 through 2012, it is possible that we will be required to pay back assessments for the period from 2003 to 2007. We are also in discussions with the FCC to obtain credit for the indirect USF payments we have made since 2003 to our wholesale telecommunications service providers. If we are unsuccessful in obtaining

29

Table of Contents

credit from the FCC for these payments, we will seek reimbursement from our wholesale telecommunication service providers. We will face a regulatory and contractual challenge in seeking recovery or credit for our USF reimbursement payments previously made to our wholesale telecommunication service providers. Finally, we are exposed to the potential assessment by the FCC of monetary penalties (or forfeitures) due to our past failure to recognize our obligation as a USF contributor. In lieu of the actual assessment of monetary forfeitures, due to our current voluntary disclosure proceeding with the FCC, we may be asked to make a voluntary contribution to the U.S. Treasury in order to resolve the FCC’s investigation amicably.

Our ongoing obligations to pay federal, state and local telecommunications contributions and taxes may decrease our price advantage over our competitors who have historically paid these contributions and taxes and could also make us less competitive with those competitors who are not subject to, or choose not to comply with, those requirements. In addition, if we are unable to continue to pass some or all of the cost of these contributions and taxes to our clients, our profit margins on the minutes we resell will decrease. Our federal contributions and tax obligations may significantly increase in the future, due to new interpretations by governing authorities, governmental budget pressures, changes in our business model or solutions or other factors. See Note 9 to the notes to our consolidated financial statements.

If we do not comply with FCC rules and regulations, we could be subject to FCC enforcement actions, fines, loss of licenses and possibly restrictions on our ability to operate or offer certain of our services.

Since our business is regulated by the FCC, we are subject to existing or potential FCC regulations relating to privacy, disability access, porting of numbers, USF contributions and other requirements. If we do not comply with FCC rules and regulations, we could be subject to FCC enforcement actions, fines, loss of licenses and possibly restrictions on our ability to operate or offer certain of our services. Any enforcement action by the FCC, which may be a public process, would hurt our reputation in the industry, possibly impair our ability to sell our services to clients and could harm our business and results of operations.

Among the regulations to which we are subject, we must comply (in whole or in part) with:

If we do not comply with any current or future rules or regulations that apply to our business, we could be subject to substantial fines and penalties, we may have to restructure our service offerings, exit certain markets, accept lower margins or raise the price of our services, any of which could ultimately harm our business and results of operations.

Reform of federal and state USF programs could increase the cost of our service to our clients, diminishing or eliminating our pricing advantage.

The FCC and a number of states are considering reform or other modifications to USF programs. The way we calculate our contribution may change if the FCC or certain states engage in reform or adopt other modifications. In April 2012, the FCC released a Further Notice of Proposed Rulemaking to consider reforms to the manner in which companies like us contribute to the federal USF program. In general, the Further Notice of Proposed Rulemaking is considering questions like: what companies should contribute, how contributions should be assessed, and methods to improve the administration of the system. We cannot predict the outcome of this proceeding nor its impact on our business at this time.

30

Table of Contents

Should the FCC or certain states adopt new contribution mechanisms or otherwise modify contribution obligations that increase our contribution burden, we will either need to raise the amount we currently collect from our clients to cover this obligation or absorb the costs, which would reduce our profit margins. Furthermore, the FCC has ruled that states can require us to contribute to state USF programs. A number of states already require us to contribute, while others are actively considering extending their programs to include the solution we provide. We currently pass through USF contributions to our clients which may result in our solution becoming less competitive as compared to those provided by our competitors.

Privacy concerns and domestic or foreign laws and regulations may reduce the demand for our solution, increase our costs and harm our business.

Our clients can use our solution to collect, use and store information, including personally identifiable information or other information treated as confidential, regarding their customers and potential customers. Federal, state and foreign government bodies and agencies have adopted, are considering adopting, or may adopt laws and regulations, including the Health Insurance Portability and Accountability Act of 1996, regarding the collection, use, storage and disclosure of such information obtained from consumers and individuals. The costs of compliance with, and other burdens imposed by, such laws and regulations that are applicable to the businesses of our clients may limit the use and adoption of our solution and reduce overall demand, or lead to significant fines, penalties or liabilities for any noncompliance with such privacy laws. Furthermore, privacy concerns may cause consumers to resist providing the personal data necessary to allow our clients to use our solution effectively. Even the perception of privacy concerns, whether or not valid, may inhibit market adoption of our solution in certain industries or countries.

Domestic and international legislative and regulatory initiatives may harm our clients’ ability to process, handle, store, use and transmit information, including demographic and personally identifiable information or other information treated as confidential, regarding their customers, which could reduce demand for our solution. The European Union and many countries in Europe have particularly stringent privacy laws and regulations, which may impact our ability to profitably operate in certain European countries.

In addition to government activity, privacy advocacy groups and the technology and other industries are considering various new, additional or different self-regulatory standards that may place additional burdens on us. If the processing of information were to be curtailed in this manner, our solution may be less attractive, which may reduce demand for our solution and harm our business.

Risks Related to Ownership of Our Common Stock and this Offering

There has been no prior market for our common stock and an active market may not develop or be sustained and investors may not be able to resell their shares at or above the initial public offering price.

There has been no public market for our common stock prior to this offering. The initial public offering price for our common stock will be determined through negotiations between the underwriters and us and may vary substantially from the market price of our common stock following this offering. If you purchase shares of our common stock in this offering, you may not be able to resell those shares at or above the initial public offering price. An active or liquid market in our common stock may not develop upon completion of this offering or, if it does develop, may not be sustained.

Our stock price may be volatile or may decline, including due to factors beyond our control, resulting in substantial losses for investors purchasing shares in this offering.

The trading prices of the securities of technology companies have been highly volatile. The market price of our common stock may fluctuate significantly in response to numerous factors, many of which are beyond our control, including:

31

Table of Contents

In addition, stock markets have experienced extreme price and volume fluctuations that have affected and continue to affect the market prices of equity securities of many technology companies. Stock prices of many technology companies have fluctuated in a manner unrelated or disproportionate to the operating performance of those companies. In the past, stockholders have instituted securities class action litigation following periods of market volatility. If we were to become involved in securities litigation, it could subject us to substantial costs, divert resources and the attention of management from our business and harm our business, results of operations, financial condition, reputation and cash flows.

If securities or industry analysts do not publish research or reports about our business, or publish negative reports about our business, our share 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, our market and our competitors. We do not have any control over these analysts. If one or more of the analysts who cover us downgrade our shares or change their opinion of our shares, our share price would likely decline. If one or more of these analysts cease coverage of our company or fail to regularly publish reports on us, we could lose visibility in the financial markets, which could cause our share price or trading volume to decline.

We may invest or spend the proceeds of this offering in ways with which you may not agree or in ways which may not yield a return.

We intend to use the net proceeds from this offering for general corporate purposes, which we expect to include growing our business by expanding our direct sales force and investing to grow our international client base, as well as other working capital, operating expenses and capital expenditures. Additionally, we may use a portion of the net proceeds to acquire complementary businesses, technologies or other assets. Our management

32

Table of Contents

will have considerable discretion in the application of the net proceeds, and you will not have the opportunity, as part of your investment decision, to assess whether the proceeds are being used appropriately or to influence our decisions regarding the use of proceeds. The net proceeds may be used for purposes that do not increase the value of our business, which could cause our stock price to decline.

Substantial future sales of shares of our common stock could cause the market price of our common stock to decline.

The market price of shares of our common stock could decline as a result of substantial sales of our common stock, particularly sales by our directors, executive officers and significant stockholders, a large number of shares of our common stock becoming available for sale or the perception in the market that holders of a large number of shares intend to sell their shares. After this offering, we will have 46,047,510 shares of our common stock outstanding, based on the number of shares outstanding as of December 31, 2013. This includes the 10,000,000 shares included in this offering, which may be resold in the public market immediately. The remaining 36,047,510 shares are currently restricted as a result of 180-day market stand-off or lock-up agreements. J.P. Morgan Securities LLC and Barclays Capital Inc. may, in their sole discretion, permit our officers, directors, employees and current stockholders who are subject to the 180-day contractual lock-up to sell shares prior to the expiration of the lock-up agreements. See “Underwriting.”

After this offering, the holders of an aggregate of 30,553,921 shares of our outstanding common stock as of March 6, 2014 will have rights, subject to some conditions, to require us to file registration statements covering their shares or to include their shares in registration statements that we may file for ourselves or our stockholders. We also intend to register shares of common stock that we may issue under our employee equity incentive plans. Once we register these shares, they will be able to be sold freely in the public market upon issuance, subject to existing market stand-off and/or lock-up agreements.

Purchasers in this offering will experience immediate and substantial dilution.

The initial public offering price per share will be substantially higher than the pro forma net tangible book value per share of our common stock outstanding prior to this offering. As a result, investors purchasing common stock in this offering will experience immediate dilution of $8.34 per share. 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 of common stock. In addition, we have issued options to acquire common stock at prices significantly below the initial public offering price. To the extent outstanding options are ultimately exercised, there will be further dilution to investors in this offering. In addition, if the underwriters exercise their option to purchase additional shares from us or if we issue additional equity securities, you will experience additional dilution.

The requirements of being a public company may strain our resources, divert management’s attention and affect our ability to attract and retain executive management and 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, the Dodd-Frank Act, the listing requirements of NASDAQ and other applicable securities laws, rules and regulations. Compliance with these laws, rules and regulations will increase our legal and financial compliance costs, make some activities more difficult, time-consuming or costly and increase demand on our systems and resources, particularly after we are no longer an “emerging growth company.” 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 and our costs and expenses will increase, which could harm our business and operating results. Although we have already hired additional employees to comply with these requirements, we may need to hire more employees in the future or engage outside consultants, 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 and financial compliance costs and making some

33

Table of Contents

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 their application and practice, regulatory authorities may initiate legal proceedings against us and our business may be harmed.

We will incur additional compensation costs in the event that we decide to pay our executive officers cash compensation closer to that of executive officers of other public cloud and technology companies, which would increase our general and administrative expense and could harm our profitability. Any future equity awards will also increase our compensation expenses. We also expect that being a public company and compliance with applicable rules and regulations will make it more expensive for us to obtain director and officer liability insurance, and we may be required to accept reduced coverage or incur substantially higher costs to obtain coverage. These factors could also make it more difficult for us to attract and retain qualified executive officers and members of our board of directors, particularly to serve on our audit committee and compensation committee.

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 could be advantageous to our competitors and clients and could 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 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.

We are an emerging growth company and we cannot be certain if the reduced disclosure requirements applicable to emerging growth companies will make our common stock less attractive to investors.

We are an “emerging growth company” as defined in the JOBS Act. Under the JOBS Act, emerging growth companies can delay adopting new or revised financial accounting standards until such time as those standards apply to private companies. We have irrevocably elected not to avail ourselves of this extended transition period and, therefore, we will be subject to the same new or revised accounting standards as other public companies that are not “emerging growth companies.”

For as long as we continue to be an emerging growth company, we may also take advantage of certain other exemptions from reporting requirements that are applicable to other public companies including, but not limited to, not being required to comply with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act, reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements, and exemptions from the requirements of holding a nonbinding advisory vote on executive compensation and stockholder approval of any golden parachute payments not previously approved. We cannot predict if investors will find our common stock less attractive because we will rely on these exemptions. If some investors find our common stock less attractive as a result, there may be a less active trading market for our common stock and our stock price may be more volatile or decline.

We will remain an emerging growth company until the earliest of (i) the end of the fiscal year in which the market value of our common stock that is held by non-affiliates is at least $700 million as of the last business day of our most recently completed second fiscal quarter, (ii) the end of the fiscal year in which we have total annual gross revenues of $1 billion or more during such fiscal year, (iii) the date on which we issue more than $1 billion in non-convertible debt in a three-year period or (iv) the end of the fiscal year in which the fifth anniversary of the date of this prospectus occurs.

34

Table of Contents

Anti-takeover provisions in our charter documents and under Delaware law could make an acquisition of our company more difficult, limit attempts by our stockholders to replace or remove our current management and limit the market price of our common stock.

Provisions in our amended and restated certificate of incorporation and amended and restated bylaws, as amended and restated in connection with this offering, may have the effect of delaying or preventing a change in control or changes in our management. Our amended and restated certificate of incorporation and amended and restated bylaws will include provisions that:

These provisions may frustrate or prevent any attempts by our stockholders to replace or remove our current management by making it more difficult for stockholders to replace members of our board of directors, which is responsible for appointing the members of our management. In addition, because we are incorporated in Delaware, we are governed by the provisions of Section 203 of the Delaware General Corporation Law, which generally prohibits a Delaware corporation from engaging in any of a broad range of business combinations with any “interested” stockholder for a period of three years following the date on which the stockholder became an “interested” stockholder.

Our amended and restated certificate of incorporation will provide that the Court of Chancery of the State of Delaware will be the sole and exclusive forum for substantially all disputes between us and our stockholders, which could limit our stockholders’ ability to obtain a favorable judicial forum for disputes with us or our directors, officers or employees.

Our amended and restated certificate of incorporation, which we will amend prior to the completion of this offering, and the amended and restated certificate of incorporation that we have adopted, which will become effective prior to the completion of this offering, provide that, unless we consent to the selection of an alternative forum, the Court of Chancery of the State of Delaware is the sole and exclusive forum for (1) any derivative action or proceeding brought on our behalf, (2) any action asserting a claim of breach of fiduciary duty owed by any of our directors, officers or other employees to us or to our stockholders, (3) any action asserting a claim

35

Table of Contents

arising pursuant to the Delaware General Corporation Law or (4) any action asserting a claim governed by the internal affairs doctrine. The choice of forum provision may limit a stockholder’s ability to bring a claim in a judicial forum that it finds favorable for disputes with us or our directors, officers or other employees, which may discourage such lawsuits against us and our directors, officers and other employees. Alternatively, if a court were to find the choice of forum provision contained in our amended and restated certificate of incorporation to be inapplicable or unenforceable in an action, we may incur additional costs associated with resolving such action in other jurisdictions, which could harm our business, operating results and financial condition.

We do not intend to pay dividends for the foreseeable future. If our stock price does not appreciate after you purchase our shares, you may lose some or all of your investment.

We have never declared or paid any cash dividends on our common stock. We currently intend to retain any future earnings and do not expect to pay any dividends in the foreseeable future. Any future determination to declare cash dividends will be made at the discretion of our board of directors, subject to applicable laws, and will depend on a number of factors, including our financial condition, results of operations, capital requirements, contractual restrictions, general business conditions and other factors that our board of directors may deem relevant. In addition, our secured credit agreement prohibits us and our subsidiaries from, among other things, paying any dividends or making any other distribution or payment on account of our common stock. Accordingly, investors must 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 investments.

Our directors, executive officers and significant stockholders, who after this offering will hold approximately 87% of the voting power of our outstanding capital stock, will continue to have substantial control over us after this offering and could delay or prevent a change in corporate control.

After this offering, our directors, executive officers and holders of more than 5% of our common stock, together with their affiliates, will beneficially own, in the aggregate, 87% of our outstanding common stock, on a fully diluted basis. As a result, these stockholders, acting together, have the ability to control the outcome of matters submitted to our stockholders for approval, including the election of directors and any merger, consolidation or sale of all or substantially all of our assets. In addition, these stockholders, acting together, have the ability to control the management and affairs of our company. Accordingly, this concentration of ownership might decrease the market price of our common stock by:

36

Table of Contents