| Summary of Significant Accounting Policies | Summary of Significant Accounting Policies Accounting Principles The consolidated financial statements and accompanying notes were prepared in accordance with accounting principles generally accepted in the United States ("GAAP"). Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Our estimates include the useful lives of our property and equipment and other lease-related assets, liabilities and costs and the collectability of our accounts receivable. We also use estimates in stock-based compensation, income taxes, business combinations, investments and accrued liabilities. Actual results could differ from those estimates. Foreign Currency The financial statements of our foreign subsidiaries with a functional currency other than U.S. dollars have been translated into U.S. dollars. Assets and liabilities of these subsidiaries are translated at the exchange rate in effect at each period-end. Income statement amounts are translated at the average rate of exchange prevailing during the period. Translation adjustments arising from the use of differing exchange rates from period to period are included in other comprehensive income (loss). As of December 31, 2017 and 2016 , we had a cumulative translation gain (loss) of $(11.3) million and $1.6 million , respectively. Gains and losses on foreign currency transactions are included in other income, net. Foreign currency transaction gains (losses) were $4.1 million , $(0.6) million and $0.6 million for the years ended December 31, 2017 , 2016 and 2015 , respectively. Risks and Uncertainties Inherent in our business are various risks and uncertainties, including our limited history of operating our business at its current scale and development of advanced technologies in a rapidly changing industry. These risks include our ability to manage our growth and our ability to attract new customers and expand sales to existing customers, as well as other risks and uncertainties. In the event that we do not successfully implement our business plan, certain assets may not be recoverable, certain liabilities may not be paid and investments in our capital stock may not be recoverable. Our success depends upon the acceptance of our technology, development of sales and distribution channels and our ability to generate significant revenues from the sale of our technology. Segments We follow the authoritative literature that established annual and interim reporting standards for an enterprise's operating segments and related disclosures about its products and services, geographic regions and major customers. We operate our business as one operating segment. Our chief operating decision makers ("CODM") are our Chief Executive Officer and Chief Financial Officer, who review financial information presented on a consolidated basis for purposes of making operating decisions, assessing financial performance and allocating resources. Revenue Recognition We generate revenues primarily in the form of software license fees and related maintenance and services fees. Software license fees include fees from the sales of perpetual, term and subscription licenses. Maintenance and services fees primarily consist of fees for maintenance services (including support and unspecified upgrades and enhancements when and if they are available), training and professional services that are not essential to the functionality of the software. We recognize revenues when all of the following conditions are met: • there is persuasive evidence of an arrangement; • the software or services have been delivered to the customer; • the amount of fees to be paid by the customer is fixed or determinable; and • the collection of the related fees is probable. We use click-through license agreements, signed agreements and purchase orders as evidence of an arrangement. We deliver all of our software electronically. Electronic delivery occurs when we provide the customer with access to the software and license key via a secure portal. We assess whether the fee is fixed or determinable at the outset of the arrangement. Our typical terms of payment are due 30 days from delivery. We assess collectability based on a number of factors such as collection history and creditworthiness of the customer. If we determine that collectability is not probable, revenue is deferred until collectability becomes probable, generally upon receipt of cash. Substantially all of our software licenses are sold in multiple-element arrangements that include maintenance services and may include professional services and training. Vendor specific objective evidence ("VSOE") of the fair value for software licenses is not available as our software licenses are never sold without maintenance; however, VSOE generally exists for all undelivered elements and any services that are not essential to the functionality of the delivered software. Therefore, we account for delivered software licenses under the residual method. Maintenance agreements consist of fees for providing software updates on a when and if available basis and technical support for software products ("post-contract support" or "PCS") for an initial term, generally one year. We have established VSOE of the fair value for maintenance on perpetual licenses based on stated substantive renewal rates or the price when sold on a standalone basis. Stated renewal rates are considered to be substantive if they are at least 15% of the actual price charged for the software license. VSOE of the fair value for standalone maintenance contracts is considered to have been established when a substantial majority of individual sales transactions within the previous 12 months falls within a reasonably narrow range, which we have defined to be plus or minus 15% of the median sales price of actual standalone sales transactions. License arrangements may include professional services and training. In determining whether professional services and training revenues should be accounted for separately from license revenues, we evaluate: • whether such services are considered essential to the functionality of the software using factors such as the nature of the software products; • whether they are ready for use by the customer upon receipt; • the nature of the services, which typically do not involve significant customization to or development of the underlying software code; • the availability of services from other vendors; • whether the timing of payments for license revenues coincides with performance of services; and • whether milestones or acceptance criteria exist that affect the realizability of the software license fee. To date, professional services have not been considered essential to the functionality of the software. The VSOE of the fair value of our professional services and training is based on the price for these same services when they are sold separately. Revenues related to professional services are billed on a time and materials basis and are recognized as the services are performed. Revenues related to training services are billed on a fixed fee basis and are recognized as the services are delivered. Payments received in advance of services performed are deferred and recognized when the related services are performed. When software is licensed for a specified term or on a subscription basis, fees for maintenance and support are generally bundled with the license fee over the entire term of the contract. In these cases, we do not have VSOE of the fair value for maintenance and support. Revenues related to term and subscription license fees are recognized ratably over the contract term beginning on the date the customer has access to the software license key and continuing through the end of the contract term. We do not offer refunds and therefore have not recorded any sales return allowance for any of the periods presented. Upon a periodic review of outstanding accounts receivable, amounts that are deemed to be uncollectable are written off against the allowance for doubtful accounts. We account for taxes collected from customers and remitted to governmental authorities on a net basis and exclude them from revenues. Cash and Cash Equivalents We consider all highly liquid investments purchased with an original or remaining maturity of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents are recorded at cost, which approximates fair value. We maintain cash and cash equivalent balances which exceed the insured limits by the Federal Deposit Insurance Corporation. Investments We classify our investment securities as available-for-sale. Our investment securities are stated at fair value and reported in short-term investments and long-term investments. Investments in securities with maturities of less than one year, or where management's intent is to use the investments to fund current operations, are classified as short-term investments. Investments with maturities greater than one year are classified as long-term investments. Unrealized gains and losses on available-for-sale securities are excluded from net income and reported, net of tax, in other comprehensive income (loss). Realized gains and losses and declines in the value of securities judged to be other-than-temporary are determined based on the specific identification method and are included in other income, net. In order to determine whether a decline in value is other-than-temporary, we evaluate, among other factors, our intent and ability to recover the amortized cost basis of the security. Interest on securities classified as available-for-sale is included in other income, net. Accounts Receivable, Net Accounts receivable consist of amounts billed and currently due from customers. Our accounts receivable are subject to collection risk. Our gross accounts receivable is reduced for this risk by a provision for doubtful accounts. This provision is for estimated losses resulting from the inability of our customers to make required payments. It is an estimate and is regularly evaluated for adequacy by taking into consideration a combination of factors. We look at factors such as past collection experience, credit quality of the customer, age of the receivable balance and current economic conditions. These factors are reviewed to determine whether a provision for doubtful accounts should be recorded to reduce the receivable balance to the amount believed to be collectible. Activity related to our provision for doubtful accounts was as follows: Year Ended December 31, 2017 2016 2015 (in thousands) Balance at the beginning of the year $ 1,065 $ 888 $ 1,111 Bad debt expense 650 750 250 Accounts written off (712 ) (573 ) (473 ) Balance at the end of the year $ 1,003 $ 1,065 $ 888 Property and Equipment, Net Property and equipment are stated at cost, net of accumulated depreciation and amortization. Depreciation and amortization are calculated using the straight-line method over the estimated useful lives of the assets. The estimated useful lives range from approximately one to twelve years. Leasehold improvements are amortized over the shorter of the estimated useful life or the remaining lease term. When assets are retired or disposed of, the cost and accumulated depreciation are removed from the accounts, and any resulting gains or losses are included in results of operations. Maintenance and repairs that do not improve or extend the lives of the respective assets are charged to expense in the period incurred. Leases and Asset Retirement Obligations Leases are categorized at their inception as either operating or capital leases. Within some lease agreements, rent holidays and other incentives are included. Rent expense is recognized on a straight-line method, over the term of the agreement generally beginning once control of the space is achieved, without regard to deferred payment terms, such as rent holidays that defer the commencement date of required rent payments. Additionally, incentives received are treated as a reduction of expense over the term of the agreement. Liabilities are established for the present value of estimated future costs to retire leasehold improvements at the termination or expiration of a lease. A corresponding asset is recorded in the period in which the obligation is incurred. Such assets are amortized over the estimated useful life of the asset, and the recorded liabilities are accreted to the future value of the estimated retirement costs. Impairment of Long-Lived Assets We evaluate the recoverability of long-lived assets in accordance with authoritative guidance on accounting for the impairment or disposal of long-lived assets. We evaluate long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying value of these assets may not be recoverable. Such impairment is recognized in the event the carrying value of such assets exceeds their fair value. If the carrying value of the net assets assigned exceeds the fair value of the assets, then the second step of the impairment test is performed in order to determine the implied fair value. No impairment of long-lived assets occurred in the periods presented. Software Development Costs Software development costs associated with the development of new products, enhancements of existing products and quality assurance activities consists of employee, consulting and other external personnel costs. The costs incurred internally from the research and development ("R&D") of computer software products are charged to expense until technological feasibility has been established for the product. Once technological feasibility is established, all software costs are capitalized until the product is available for release to customers. Judgment is required in determining when technological feasibility of a product is established. To date, we have determined that technological feasibility of software products is reached shortly before the products are released. Costs incurred after establishment of technological feasibility have not been material, and therefore, we have expensed all R&D costs as they were incurred. R&D expenses primarily consist of personnel-related costs attributable to our R&D personnel and allocated overhead, which includes facilities-related costs. We capitalize certain costs relating to software developed or modified solely to meet our internal requirements and for which there are no substantive plans to market the software. To date, we have not capitalized any such costs as these costs have not been material. Intangible Asset Costs Costs related to filing and pursuing patent and trademark applications are expensed as incurred, as recoverability of such expenditures is uncertain. These intangible asset-related legal costs are generally reported as a component of general and administrative expenses. Advertising Expenses We expense all advertising costs as incurred and classify such costs as sales and marketing expenses. Advertising expenses for the years ended December 31, 2017 , 2016 and 2015 were $28.2 million , $21.7 million and $11.3 million , respectively. Income Taxes Income taxes are accounted for under the asset and liability method in accordance with authoritative guidance for income taxes. Deferred income tax assets are recognized for deductible temporary differences, net operating loss carryforwards, and tax credit carryforwards if it is more likely than not that the tax benefits will be realized. We consider future taxable income, historical operating results and ongoing prudent and feasible tax planning strategies in assessing the need for a valuation allowance. A valuation allowance is recorded to reduce our deferred income tax assets to the net amount that we believe is more likely than not to be realized. In the event we determine that we are able to realize our deferred income tax assets in excess of our net recorded amount, we would reduce the valuation allowance associated with the deferred income tax assets in the period the determination is made, which may result in a tax benefit in the statement of operations. Deferred income 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 on deferred income tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Our assumptions, judgments and estimates relative to the value of net deferred income taxes take into account predictions of the amount and category of future taxable income, such as income from operations or capital gains income. Actual operating results and the underlying amount and category of income in future years could render our current assumptions, judgments and estimates of recoverable net deferred income taxes inaccurate. Any of the assumptions, judgments and estimates mentioned above could cause our actual income tax obligations to differ from our estimates, thus materially impacting our financial position and results of operations. Concentrations of Credit Risk Financial instruments that potentially subject us to concentrations of credit risk consist primarily of cash and cash equivalents, investments and accounts receivable. Our investment portfolio consists of investment-grade securities diversified among security types, industries and issuers. Our cash and cash equivalents and investments are held and managed by recognized financial institutions that follow our investment policy. Our policy limits the amount of credit exposure to any one security issue or issuer. We extend credit to customers based upon an evaluation of the customer's financial condition. As of December 31, 2017 and 2016 , no individual customer accounted for 10% or more of total accounts receivable. For the years ended December 31, 2017 , 2016 and 2015 , no individual customer represented 10% or more of our total revenues. Business Combinations As of the date of an acquisition, we recognize the identifiable assets acquired and liabilities assumed at fair value. Any excess of the consideration over the fair value of identifiable net assets is recorded as goodwill. Amounts that are not part of the consideration transferred are recognized separately from a business combination and are expensed as incurred. Intangible assets acquired are measured at their acquisition date fair value using valuation techniques that are subject to judgment. Goodwill and Intangible Assets Intangible assets with a finite life are typically amortized over their useful lives which range from three to five years. Goodwill is tested for impairment on an annual basis in the third quarter and more frequently if circumstances indicate that the carrying value may not be recoverable. As part of our goodwill impairment test, we first perform a qualitative assessment to determine whether it is more likely than not that the fair value of our reporting unit is less than its carrying amount. For purposes of this assessment, we consider the enterprise to be the reporting unit. If we determine it is more likely than not that the fair value of our reporting unit is less than its carrying amount, we will perform a quantitative assessment to determine whether the fair value of our reporting unit is less than its carrying amount. We have not had any impairments of the goodwill balance. Stock-Based Compensation We record compensation expense for stock-based transactions including employee and non-employee stock option and restricted stock unit ("RSU") awards granted under our 2004 Equity Incentive Plan (the "2004 Plan") and our 2013 Equity Incentive Plan, as amended, (the "2013 Plan" and together with the 2004 Plan, the "Plans"). We also record compensation expense related to employee contributions made under our 2013 Employee Stock Purchase Plan ("2013 ESPP"). These contributions are used to purchase shares of our Class A common stock at a discount. Stock-based compensation expense is measured and recognized in the financial statements based on fair value. The fair value of each RSU award is determined based on the closing price of our Class A common stock as reported on the New York Stock Exchange on the date of grant. The fair value of each stock option award is determined at the date of grant by applying the Black-Scholes option pricing model. We also use the Black-Scholes option pricing model to determine the fair value of each common share issued under the 2013 ESPP. The fair value for 2013 ESPP grants is determined on the first day of each offering period. The Black-Scholes option pricing model utilizes the value of our underlying common stock at the measurement date, the expected or contractual term of the option or offering period, the expected volatility of our common stock, risk-free interest rates and expected dividend yield of our common stock. Prior to our IPO in May 2013, because our stock was not publicly traded we estimated the fair value of our common stock. Our board of directors considered numerous objective and subjective factors to determine the fair value of our common stock at each meeting at which awards were approved. The factors included, but were not limited to: (i) contemporaneous third-party valuations of our common stock; (ii) the prices, rights, preferences and privileges of our preferred stock that was then outstanding relative to those of our common stock; (iii) the lack of marketability of our common stock; (iv) our actual operating and financial results; (v) current business conditions and projections; and (vi) the likelihood of achieving a liquidity event, such as an IPO or merger or acquisition, given prevailing market conditions. After the completion of our IPO, our common stock has been valued by reference to the closing price of our Class A common stock as reported on the New York Stock Exchange. We recognize stock-based compensation expense using the straight-line method over the requisite service period. We account for forfeitures as they occur. For awards subject to technology milestones, we recognize compensation cost over the required service period if it is probable that the technology milestone will be met. If our assessment of the probability of the technology milestone being met changes, we recognize the impact of the change in estimate in the period of the change. Excess tax benefits resulting from the settlement of stock awards are recorded to income tax expense. Fair Value Measurements We categorize assets and liabilities recorded at fair value on our consolidated balance sheets based upon the level of judgment associated with inputs used to measure their fair value. The levels of the fair value hierarchy are as follows: • Level 1—Inputs are unadjusted quoted prices in active markets for identical assets or liabilities. • Level 2—Inputs are quoted prices for similar assets and liabilities in active markets or quoted prices for identical or similar instruments in markets that are not active and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets. • Level 3—Inputs are unobservable inputs based on our own assumptions and valuation techniques used to measure assets and liabilities at fair value. The inputs require significant management judgment or estimation. Our assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy levels. We establish fair value of our assets and liabilities using the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date and using a fair value hierarchy based on the inputs used to measure fair value. The carrying amounts reported in the consolidated financial statements approximate the fair value for cash equivalents, accounts receivable, accounts payable, and accrued and other current liabilities, due to their short-term nature. We value our investments using quoted prices for identical instruments in active markets when available. If we are unable to obtain quoted prices for identical instruments in active markets, we value our investments using quoted market prices for comparable instruments. To date, all of our investments can be valued using one of these two methodologies. Recently Adopted Accounting Pronouncements In March 2016, the Financial Accounting Standards Board ("FASB") issued ASU 2016-09 related to stock-based compensation. The guidance, which simplifies the accounting and presentation for share-based payments, provides for a number of amendments that impact the accounting for income taxes and the accounting for forfeitures. We adopted this standard in the first quarter of 2017. Upon adoption, we recognized all of the previously unrecognized excess tax benefits related to stock awards using the modified retrospective transition method . These excess tax benefits, recognized upon adoption, were recorded as a deferred tax asset, which was then fully offset by our U.S. federal and state deferred tax asset valuation allowance resulting in no impact to our accumulated deficit. Without the valuation allowance, our deferred tax asset would have increased by $180.9 million . Immediately prior to adoption, we had no unrecognized excess tax benefits related to stock awards in jurisdictions outside the United States. All future excess tax benefits resulting from the settlement of stock awards will be recorded to income tax expense. Prior to the adoption of ASU 2016-09, excess tax benefits related to stock awards were required to be presented as an inflow from financing activities and an outflow from operating activities on the statement of cash flows. Under the new standard, all tax-related cash flows resulting from share-based payments are reported as operating activities. We adopted the new requirement retrospectively, and for the years ended December 31, 2016 and December 31, 2015 , this resulted in an increase to net cash provided by operating activities of $2.2 million and $5.6 million , and a corresponding decrease to net cash provided by (used in) financing activities of $2.2 million and $5.6 million , respectively. Also, as part of the adoption of the standard, we made the policy election to account for forfeitures as they occur. Using the modified retrospective adoption method, we recognized a $0.4 million cumulative-effect increase to our accumulated deficit for previously estimated forfeitures. In January 2017, the FASB issued ASU 2017-04, simplifying the accounting for goodwill impairment. The new guidance removes step two of the two-step quantitative goodwill impairment test, which requires a hypothetical purchase price allocation. We adopted this standard in the third quarter of 2017 as part of our annual goodwill impairment testing. The adoption of this standard did not impact these consolidated financial statements. Recent Accounting Pronouncements Not yet Adopted In May 2014, the FASB issued ASU 2014-09 related to revenue recognition. Since the issuance of ASU 2014-09, the FASB has also issued ASU 2016-08, ASU 2016-10, ASU 2016-12, ASU 2016-20 and ASU 2017-14, all of which clarify certain aspects of ASU 2014-09. The new standard will change the way we recognize revenue, including the identification of contractual performance obligations and the allocation of transaction price, to depict the transfer of promised goods or services to customers at the amount that reflects the consideration to which we expect to be entitled in exchange for those goods or services. We will adopt this standard effective January 1, 2018 on a modified retrospective basis and apply the new standard only to contracts that are not completed contracts at January 1, 2018. The new standard will materially impact the timing of revenue recognition related to our on-premises term license agreements. We have historically recognized revenue related to on-premises term license agreements ratably over the term of the licensing agreement. Under the new standard, revenue allocable to the license portion of the arrangement will be recognized upon delivery of the license. Maintenance revenue related to on-premises term license agreements will continue to be recognized ratably over the term of the licensing agreement. The new standard will also impact our determination of standalone selling prices, which will impact the allocation of transaction price to each performance obligation, thereby impacting the timing of revenue recognition depending on when each performance obligation is recognized. The impacts to the timing of revenue recognition will also affect our deferred revenue balance. As of December 31, 2017, we had $142 million of on-premises deferred license revenue on our balance sheet. Upon adoption, a portion of this amount will be recorded to retained earnings for the impacts from the allocation of standalone selling prices under the new standard. The new standard also requires the capitalization of certain incremental costs of obtaining a contract, which will impact the period in which we record our sales commissions expense. We have historically recognized sales commissions expense upfront. Under the new guidance, we are required to recognize these expenses consistently with the transfer of goods or services. This will result in a deferral of some sales compensation costs. We will amortize these deferred costs on a straight-line basis over four years. The new standard will also impact our internal control environment, including our financial statement disclosure controls, our business process controls and enhancements necessary to update our business systems. We are currently finalizing the implementation controls necessary to adopt this new standard. In February 2016, the FASB issued ASU 2016-02 related to lease accounting. The new guidance will require lessees to recognize right-of-use assets and lease liabilities on the balance sheet for operating leases that do not meet the definition of a short-term lease. ASU 2016-02 is effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2018 and requires modified retrospective transition. Under the new standard we anticipate that our current real estate leases will continue to be classified as operating leases and a significant amount of our currently outstanding operating lease commitments will be recorded to the balance sheet as a right-of-use asset and a corresponding lease liability. Our evaluation of the new standard will extend into future periods and we will update our disclosures, including the expected impacts of the new standard, as we progress towards the required adoption date. In June 2016, the FASB issued ASU 2016-13, related to credit losses. The new guidance replaces the existing incurred loss impairment model with an expected credit loss model and requires a financial asset measured at amortized cost to be presented at the net amount expected to be collected. ASU 2016-13 is effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2019. Early adoption is permitted. We are currently evaluating the impact that this standard will have on our consolidated financial statements. In October 2016, the FASB issued ASU 2016-16 related to the accounting for income tax effects on intra-entity asset transfers of assets other than inventory. The new guidance will require reporting entities to recognize tax expense from the sale of assets when the transfer occurs, even though the pre-tax effects of the transaction are eliminated in consolidation. We will adopt the new standard, in the first quarter of 2018, on a modified retrospective basis. We are currently evaluating the impact that this standard will have on our consolidated financial statements. |
