Summary of Significant Accounting Policies | 2. Summary of Significant Accounting Policies Basis of P resentation These consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States, or GAAP. The condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Certain prior period amounts have been reclassified to confirm to the current period presentation. Use of Estimates The preparation of the accompanying consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenues and expenses. Significant items subject to such estimates include allowance for doubtful accounts, stock-based compensation, acquired intangible assets, the useful lives of intangible assets and property and equipment, and income taxes. In accordance with GAAP, management bases its estimates on historical experience and on various other assumptions that management believes are reasonable under the circumstances. Management regularly evaluates its estimates and assumptions using historical experience and other factors; however, actual results could differ from those estimates. Cash and Cash Equivalents Cash and cash equivalents consist of cash deposits and liquid investments with original maturities of three months or less when purchased. Cash equivalents are stated at cost, which approximates market value, because of the short maturity of these instruments. Accounts Receivable and Allowance for Doubtful Accounts The Company extends credit to the majority of its customers. Issuance of credit is based on ongoing credit evaluations by the Company of customers’ financial condition and generally requires no collateral. Trade accounts receivable are recorded at the invoiced amount and do not bear interest. Invoices generally require payment within 30 days from the invoice date. The Company generally does not charge interest on past due payments, although the Company's contracts with its customers usually allow it to do so. The Company maintains an allowance for doubtful accounts to reserve for potential uncollectible receivables. The allowance is based upon the creditworthiness of the Company’s customers, the customers’ historical payment experience, the age of the receivables and current market conditions. Provisions for potentially uncollectible accounts are recorded in sales and marketing expenses. The Company writes off accounts receivable balances to the allowance for doubtful accounts when it becomes likely that they will not be collected. The following table presents the changes in the allowance for doubtful accounts (in thousands): Year Ended December 31, 2015 2014 2013 Balance at beginning of year $ 890 $ 454 $ 321 Provision 412 829 725 Acquisitions — 400 295 Writeoffs, net of recoveries (721 ) (793 ) (887 ) Balance at end of year $ 581 $ 890 $ 454 Concentrations of Credit Risk and Significant Customers Financial instruments that potentially subject the Company to credit risk consist of cash and cash equivalents and accounts receivable. The Company’s cash and cash equivalents are placed with high-quality financial institutions, which, at times, may exceed federally insured limits. The Company has not experienced any losses in these accounts, and the Company does not believe it is exposed to any significant credit risk related to cash and cash equivalents. The Company provides credit, in the normal course of business, to a number of its customers. The Company performs periodic credit evaluations of its customers and generally does not require collateral. No individual customer represented more than 10% of total revenues or more than 10% of accounts receivable in the years ended December 31, 2015 , 2014 , or 2013 . Property and Equipment Property and equipment are carried at cost, less accumulated depreciation and amortization. Depreciation of property and equipment is computed using the straight-line method over each asset’s useful life. Leasehold improvements are amortized over the shorter of the lease term or of the estimated useful lives of the related assets. Upon retirement or disposal, the cost of each asset and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is credited or charged to income. Repairs, maintenance, and minor replacements are expensed as incurred. The estimated useful lives of property and equipment are as follows: Computer hardware and equipment 3 - 5 years Purchased software and licenses 3 - 5 years Furniture and fixtures 7 years Leasehold improvements Lesser of estimated useful life or lease term Goodwill and Other Intangibles Goodwill arises from business combinations and is measured as the excess of the cost of the business acquired over the sum of the acquisition-date fair value of tangible and identifiable intangible assets acquired, less any liabilities assumed. Goodwill is evaluated for impairment annually or more frequently when an event occurs or circumstances change that indicate the carrying value may not be recoverable. The events and circumstances considered by the Company include the business climate, legal factors, operating performance indicators and competition. The Company evaluates the recoverability of goodwill using a two-step impairment process tested at the reporting unit level. The Company has one reporting unit for goodwill impairment purposes. In the first step, the fair value of the reporting unit is compared to the book value, including goodwill. In the case that the fair value is less than the book value, a second step is performed that compares the implied fair value of goodwill to the book value of goodwill. The fair value for the implied goodwill is determined based on the difference between the fair value of the reporting unit and the net fair value of the identifiable assets and liabilities, excluding goodwill. If the implied fair value of the goodwill is less than the book value, the difference is recognized as an impairment charge in the consolidated statement of operations. No goodwill impairment charges were recorded during the years ended December 31, 2015 , 2014 , or 2013 . Identifiable intangible assets consist of customer relationships, marketing-related intangible assets and developed technology. Intangible assets with definite lives are amortized over their estimated useful lives on a straight-line basis. The straight-line method of amortization represents the Company’s best estimate of the distribution of the economic value of the identifiable intangible assets. Intangible assets are reviewed for impairment whenever events or changes in circumstances indicate the carrying amount of intangible assets may not be recoverable. Conditions that would necessitate an impairment assessment include a significant decline in the observable market value of an asset, a significant change in the extent or manner in which an asset is used or any other significant adverse change that would indicate that the carrying amount of an asset or group of assets may not be recoverable. The Company evaluates the recoverability of intangible assets by comparing their carrying amounts to the future net undiscounted cash flows expected to be generated by the intangible assets. If such intangible assets are considered to be impaired, the impairment to be recognized is measured as the amount by which the carrying amount of the intangible assets exceeds the fair value of the assets. The Company determines fair value based on discounted cash flows using a discount rate commensurate with the risk inherent in the Company’s current business model for the specific intangible asset being valued. The Company determined there was an impairment of the PowerSteering trade name of $1.1 million during 2013. There were no such impairments during 2015 and 2014 . Long-Lived Assets Long-lived assets are reviewed for impairment whenever events or circumstances indicate their carrying value may not be recoverable. When such events or circumstances arise, an estimate of future undiscounted cash flows produced by the asset, or the appropriate grouping of assets, is compared to the asset's carrying value to determine whether impairment exists. If the asset is determined to be impaired, the impairment loss is measured based on the excess of its carrying value over its fair value. Assets to be disposed of are reported at the lower of the carrying value or net realizable value. No indicators of impairment were identified during the years ended December 31, 2015 , 2014 , or 2013 . Software Development Costs Software development costs are expensed as incurred until the point the Company establishes technological feasibility. Technological feasibility is established upon the completion of a working model. Costs incurred by the Company between establishment of technological feasability and the point at which the product is ready for general release are capitalized, subject to their recoverability, and amortized over the economic life of the related products. Because the Company believes its current process for developing its software products essentially results in the completion of a working product concurrent with the establishment of technological feasibility, no software development costs have been capitalized to date. There were no software development costs required to be capitalized under ASC 985-20, Costs of Software to be Sold, Leased or Marketed, and under ASC 350-40, Internal-Use Software. Canadian Tax Credits Canadian tax credits related to current expenses are accounted for as a reduction of the research and development costs. Such credits relate to the Company's operations in Canada and are not dependent upon taxable income. Credits are accrued in the year in which the research and development costs or the capital expenditures are incurred, provided the Company is reasonably certain that the credits will be received. The government credit must be examined and approved by the tax authorities, and it is possible that the amounts granted will differ from the amounts recorded. Deferred Financing Costs The Company capitalizes underwriting, legal, and other direct costs incurred related to the issuance of debt, which are recorded as deferred charges and amortized to interest expense over the term of the related debt using the effective interest rate method. Upon the extinguishment of the related debt, any unamortized capitalized deferred financing costs are recorded to interest expense. In 2014, the Company wrote off approximately $0.4 million of deferred financing costs associated with a financing facility no longer required after the initial public offering. In 2013, the Company wrote off approximately $0.2 million of deferred financing costs in connection with the refinancing of its debt facility. In 2015, the Company wrote off approximately $0.2 million of deferred financing costs associated with its Comerica facility replaced by the new Wells Fargo facility. Fair Value of Financial Instruments The Company accounts for financial instruments in accordance with the authoritative guidance on fair value measurements and disclosures for financial assets and liabilities. This guidance defines fair value, establishes a framework for measuring fair value in accordance with GAAP, and expands disclosures about fair value measurements. The guidance also establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include Level 1, defined as observable inputs, such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore, requiring an entity to develop its own assumptions. The Company’s financial instruments consist principally of cash and cash equivalents, accounts receivable, and accounts payable, long–term debt and warrant liabilities. The carrying value of cash and cash equivalents, accounts receivable, and accounts payable approximate fair value, primarily due to short maturities. The carrying values of the Company’s debt instruments approximated their fair value based on rates currently available to the Company. The carrying values of warrant liabilities are marked to the market at each reporting period. Revenue Recognition The Company derives revenue from product revenue, consisting of subscription, support and perpetual licenses, and professional services revenues. The Company recognizes revenue when all of the following criteria are met: persuasive evidence of an arrangement exists, delivery of the product or services has occurred, no Company obligations with regard to implementation considered essential to the functionality remain, the fee is fixed or determinable and collectability is probable. Subscription and Support Revenue The Company derives subscription revenues by providing its software-as-a-service solution to customers in which the customer does not have the right to take possession of the software, but can use the software for the contracted term. The Company accounts for these arrangements as service contracts. Subscription and support revenues are recognized on a straight-line basis over the term of the contractual arrangement, typically one to three years. Amounts that have been invoiced and that are due are recorded in deferred revenue or revenue, depending on when the criteria for revenue recognition are met. Revenue from usage-based services are recognized in the month in which such usage is reported. The Company may provide hosting services to customers who purchased a perpetual license. Such hosting services are recognized ratably over the applicable term of the arrangement. These hosting arrangements are typically for a period of one to three years. Software maintenance agreements provide technical support and the right to unspecified upgrades on an if-and-when-available basis. Revenue from maintenance agreements is recognized ratably over the life of the related agreement, which is typically one year. Perpetual License Revenue The Company also records revenue from the sales of proprietary software products under perpetual licenses. For license agreements in which customer acceptance is a condition to earning the license fees, revenue is not recognized until acceptance occurs. The Company’s products do not require significant customization. Revenue on arrangements with customers who are not the ultimate users (primarily resellers) is not recognized until the product is delivered to the end user. Perpetual licenses are sold along with software maintenance and, sometimes, hosting agreements. When vendor specific objective evidence (VSOE) of fair value exists for the software maintenance and hosting agreement, the perpetual license is recognized under the residual method whereby the fair value of the undelivered software maintenance and hosting agreement is deferred and the remaining contract value is recognized immediately for the delivered perpetual license. When VSOE of fair value does not exist for the either the software maintenance or hosting agreement, the entire contract value is recognized ratably over the underlying software maintenance and/or hosting period. Professional Services Revenue Professional services provided with perpetual licenses consist of implementation fees, data extraction, configuration, and training. The Company’s implementation and configuration services do not involve significant customization of the software and are not considered essential to the functionality. Revenues from professional services are recognized as such services are provided when VSOE of fair value exists for such services and all undelivered elements such as software maintenance and/or hosting agreements. VSOE of fair value for services is based upon the price charged when these services are sold separately, and is typically an hourly rate. When VSOE of fair value does not exist for software maintenance and/or hosting agreements, revenues from professional services are recognized ratably over the underlying software maintenance and/or hosting period. Professional services, when sold with the subscription arrangements, are accounted for separately when these services have value to the customer on a standalone basis and there is objective and reliable evidence of fair value for each deliverable. When accounted for separately, revenues are recognized as the services are rendered for time and material contracts. For those arrangements where the elements do not qualify as a separate unit of accounting, the Company recognizes professional services ratably over the contractual life of the related application subscription arrangement. Currently, all professional services are accounted for separately as all have value to the customer on a standalone basis. Multiple Element Arrangements The Company enters into arrangements with multiple-element that generally include subscriptions and implementation and other professional services. For multiple-element arrangements, arrangement consideration is allocated to deliverables based on their relative selling price. In order to treat deliverables in a multiple-element arrangement as separate units of accounting, the elements must have standalone value upon delivery. If the elements have standalone value upon delivery, each element must be accounted for separately. The Company’s subscription services have standalone value as such services are often sold separately. In determining whether implementation and other professional services have standalone value apart from the subscription services, the Company considers various factors including the availability of the services from other vendors. The Company has concluded that the implementation services included in multiple-element arrangements have standalone value. As a result, when implementation and other professional services are sold in a multiple-element arrangement, the arrangement consideration is allocated to the identified separate units based on a relative selling price hierarchy. The selling price for a element is based on its VSOE of selling price, if available, third-party evidence of selling price, or TPE, if VSOE is not available or best estimate of selling price, or BESP, if neither VSOE nor TPE is available. The Company has not established VSOE for its subscription services due to lack of pricing consistency, the introduction of new services and other factors. The Company has determined that TPE is not a practical alternative due to differences in its service offerings compared to other parties and the availability of relevant third-party pricing information. Accordingly, the Company uses BESP to determine the relative selling price. The Company determined BESP by considering its overall pricing objectives and market conditions. Significant pricing practices taken into consideration include the Company’s discounting practices, the size and volume of its transactions, customer characteristics, price lists, go-to-market strategy, historical standalone sales and agreement prices. As the Company’s go-to-market strategies evolve, it may modify its pricing practices in the future, which could result in changes in relative selling prices, and include both VSOE and BESP. Deferred Revenue Deferred revenue represents either customer advance payments or billings for which the aforementioned revenue recognition criteria have not yet been met. Messaging-related Revenue The Company recognizes subscription revenue for its digital engagement application which provides short code connectivity for its two-way SMS programs and campaigns. The Company evaluates whether it is appropriate to recognize revenue based on the gross amount billed to its customers for these services. Since the Company is primarily obligated in these transactions, has latitude in establishing prices associated with its messaging program management services, is responsible for fulfillment of the transaction, and has credit risk, revenue is recorded on a gross basis. While none of the factors individually are considered presumptive or determinative, in reaching conclusions on gross versus net revenue recognition, the Company places the most weight on the analysis of whether or not it is the primary obligor in the arrangement. Cost of Revenue Cost of revenue primarily consists of salaries and related expenses (e.g. bonuses, employee benefits, and payroll taxes) for personnel directly involved in the delivery of services and products directly to customers. Cost of revenue also includes the amortization of acquired technology. Customer Contract Acquisition Costs Costs associated with the acquisition or origination of customer contracts are expensed as incurred. Customer Relationship Acquisition Costs Costs associated with the acquisition or origination of customer relationships are capitalized as customer relationship assets as incurred and amortized over the life of the acquired contracts. Advertising Costs Advertising costs are expensed in the period incurred. Advertising expenses included in sales and marketing expense were $347,000 $283,000 and $175,000 for the years ended December 31, 2015 , 2014 , or 2013 , respectively. Advertising costs are recorded in sales and marketing expenses in the accompanying consolidated statement of operations. Income Taxes The Company uses the asset and liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are recognized for the expected future tax consequences of temporary differences between the carrying amounts and the tax bases of assets and liabilities. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of a change in tax rates on deferred tax assets and liabilities will be recognized in the period that includes the enactment date. A valuation allowance is established against the deferred tax assets to reduce their carrying value to an amount that is more likely than not to be realized. The Company accounts for uncertainty of income taxes based on a “more likely than not” threshold for the recognition and derecognition of tax positions, which includes the accounting for interest and penalties. Stock-Based Compensation Stock options awarded to employees and directors are measured at fair value at each grant date. The Company accounts for stock-based compensation in accordance with authoritative accounting principles which require all share-based compensation to employees, including grants of employee stock options, to be recognized in the financial statements based on their estimated fair value. Compensation expense is determined under the fair value method using the Black-Scholes option pricing model and recognized ratably over the period the awards vest. The Black-Scholes option pricing model used to compute share-based compensation expense requires extensive use of accounting judgment and financial estimates. Items requiring estimation include the expected term option holders will retain their vested stock options before exercising them, the estimated volatility of the Company’s common stock price over the expected term of each stock option, and the number of stock options that will be forfeited prior to the completion of their vesting requirements. Application of alternative assumptions could result in significantly different share-based compensation amounts being recorded in the financial statements. The following table summarizes the weighted-average grant-date fair value of options granted in 2015 , 2014 , and 2013 and the assumptions used to develop their fair values. As there was no public market for its common stock prior to November 2014, the Company estimates the volatility of its common stock based on the volatility of publicly traded shares of comparable companies' common stock. The Company's decision to use the volatility of comparable stock was based upon the Company's assessment that this information is more representative of future stock price trends than the Company's historical volatility. The Company estimates the expected term using the simplified method, which calculates the expected term as the midpoint between the vesting date and the contractual termination date of each award. The dividend yield assumption is based on historical and expected future dividend payouts. The risk-free interest rate is based on observed market interest rates appropriate for the term of each options. Year Ended December 31, 2015 2014 2013 Weighted average grant-date fair value of options $3.01 $3.76 $0.91 Expected volatility 42.5% - 44.0% 54.1% - 55.2% 53.3% Risk-free interest rate 1.7% - 1.9% 1.6% - 1.9% 1.6% Expected life in years 5.93 6.29 6.29 Dividend yield — — — Comprehensive Loss The Company utilizes the guidance in Accounting Standards Codification (ASC) Topic 220, Comprehensive Income, for the reporting and display of comprehensive loss and its components in the consolidated financial statements. Comprehensive loss comprises net loss and cumulative foreign currency translation adjustments. The accumulated comprehensive loss as of December 31, 2015 , 2014 , and 2013 was due to foreign currency translation adjustments. Foreign Currency Transactions Results of operations for foreign subsidiaries are translated in United State dollars using the average exchange rates on a monthly basis during the year. The assets and liabilities of those subsidiaries are translated into United States dollars using the exchange rates at the balance sheet date. The related translation adjustments are recorded in a separate component of stockholders' equity in accumulated other comprehensive loss. Foreign currency transaction gains and losses are included in the statements of operations and include the impact of revaluation of certain foreign currency denominated net assets or liabilities held internationally. For the years ended December 31, 2015 , 2014 , and 2013 , foreign currency transaction losses were $515,000 , $2,000 and $550,000 , respectively. Basic and Diluted Net Loss per Common Share The Company uses the two-class method to compute net loss per common share because the Company has issued securities, other than common stock, that contractually entitle the holders to participate in dividends and earnings of the Company. The two-class method requires earnings for the period to be allocated between common stock and participating securities based upon their respective rights to receive distributed and undistributed earnings. Holders of the Company’s Series A, B, B-1, B-2 and C preferred stock are entitled, on a pari passu basis, to receive dividends when, as, and if declared by the board of directors, prior and in preference to any declaration or payment of any dividend on the common stock until such time as the total dividends paid on each share of Series A, B, B-1, B-2 and C preferred stock is equal to the original issue price of the shares. As a result, all series of the Company’s preferred stock are considered participating securities. All of the outstanding preferred stock was converted to common stock upon the Company's initial public offering in November 2014. Under the two-class method, for periods with net income, basic net income per common share is computed by dividing the net income attributable to common stockholders by the weighted-average number shares of common stock outstanding during the period. Net income attributable to common stockholders is computed by subtracting from net income the portion of current year earnings that the participating securities would have been entitled to receive pursuant to their dividend rights had all of the year’s earnings been distributed. No such adjustment to earnings is made during periods with a net loss, as the holders of the participating securities have no obligation to fund losses. Diluted net loss per common share is computed under the two-class method by using the weighted-average number of shares of common stock outstanding plus, for periods with net income attributable to common stockholders, the potential dilutive effects of stock options and warrants. In addition, the Company analyzes the potential dilutive effect of the outstanding participating securities under the if-converted method when calculating diluted earnings per share, in which it is assumed that the outstanding participating securities convert into common stock at the beginning of the period. The Company reports the more dilutive of the approaches as its diluted net income per share during the period. Due to net losses for the years ended December 31, 2015 , 2014 , and 2013 , basic and diluted net loss per share were the same, as the effect of all potentially dilutive securities would have been anti-dilutive. Recent Accounting Pronouncements In May 2014, the FASB issued FASB ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), which supersedes the revenue recognition requirements in ASC 605, Revenue Recognition. The core principle of ASU 2014-09 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance provides a five-step process to achieve that core principle. ASU 2014-09 requires disclosures enabling users of financial statements to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. Additionally, qualitative and quantitative disclosures are required about contracts with customers, significant judgments and changes in judgments, and assets recognized from the costs to obtain or fulfill a contract. In August 2015, the FASB issued FASB ASU No. 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, which deferred the effective date of ASU 2014-09 by one year. ASU 2014-09 is now effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period, using one of two retrospective application methods. Early application is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. The Company is currently evaluating the effect that the adoption of ASU 2014-09 and ASU 2015-14 will have on its financial statements. In August 2014, the FASB issued FASB ASU No. 2014-15, Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern. The new standard provides guidance around management's responsibility to evaluate whether there is substantial doubt about an entity's ability to continue as a going concern and to provide related footnote disclosures. The new standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2016, with early adoption permitted. The adoption of this standard is not expected to have a material impact on the Company's financial statements. In April 2015, the FASB issued FASB ASU No. 2015-03 Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs. Under this revised guidance, debt issuance costs should be presented in the balance sheet as a direct deduction from the carrying value of the associated debt, consistent with the presentation of a debt discount. The recognition and measurement guidance for debt issuance costs are not affected by the amendments in this update. This revised guidance is effective for annual periods beginning after December 15, 2015, and interim periods within those fiscal years, with early adoption permitted. The Company has adopted this standard in the second quarter of 2015. The December 31, 2014 balance sheet was retrospectively adjusted to reclassify $0.1 million from Other non-current assets to a reduction of the Notes payable liability. In September 2015, the FASB issued ASU 2015-16, Business Combinations (Topic 805): Simplifying the Acco |