| Basis of Presentation and Summary of Significant Accounting Policies | Basis of Presentation and Summary of Significant Accounting Policies Principles of Consolidation The consolidated financial statements include the accounts of the company and our wholly owned subsidiaries and have been prepared in conformity with accounting principles generally accepted in the United States (U.S. GAAP). All intercompany balances and transactions have been eliminated in consolidation. Foreign Currency The functional currency of our foreign subsidiaries is the U.S. dollar. Transactions denominated in currencies other than the functional currency are remeasured to the functional currency at the average exchange rate in effect during the period. At the end of each reporting period, monetary assets and liabilities are remeasured using exchange rates in effect at the balance sheet date. Non-monetary assets and liabilities are remeasured at historical exchange rates. Foreign currency transaction gains and losses are recorded in other income (expense), net in the consolidated statements of operations. For the years ended January 31, 2015 , 2016 and 2017 , we recorded net foreign currency transaction losses of $648,000 , $2.3 million, and $2.6 million, respectively. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported and disclosed in the financial statements and accompanying notes. Actual results could differ from these estimates. Such estimates include, but are not limited to, the determination of best estimate of selling price included in multiple-deliverable revenue arrangements, sales commissions, useful lives of intangible assets and property and equipment, fair values of stock-based awards, provision for income taxes, including related reserves, and contingent liabilities, among others. Management bases its estimates on historical experience and on various other assumptions which management believes to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Concentration Risk Financial instruments that are exposed to concentration of credit risk consist primarily of cash and cash equivalents and accounts receivable. As of January 31, 2016 and 2017 , substantially all of our cash and cash equivalents have been invested with three financial institutions and such deposits exceed federally insured limits. Management believes that the financial institutions that hold our investments are financially sound and, accordingly, are subject to minimal credit risk. We define a customer as an end user that purchases our products and services from one of our channel partners or from us directly. Our revenue and accounts receivable are derived substantially from the United States across a multitude of industries. We perform ongoing evaluations to determine customer credit. As of January 31, 2016 , we had two channel partners that individually represented 11% of total accounts receivable on that date. As of January 31, 2017 , we had one channel partner that represented 10% of total accounts receivable on that date. No single channel partner represented over 10% of revenue for the years ended January 31, 2015 and 2016. One channel partner represented 11% of revenue for the year ended January 31, 2017. No customer represented over 10% of revenue for the years ended January 31, 2015 , 2016 and 2017 . We rely on a limited number of suppliers for our contract manufacturing and certain raw material components. In instances where suppliers fail to perform their obligations, we may be unable to find alternative suppliers or satisfactorily deliver our products to our customers on time. Cash and Cash Equivalents Cash and cash equivalents consist of cash in banks and highly liquid investments, primarily money market funds, purchased with an original maturity of three months or less. Restricted Cash Restricted cash is comprised of cash collateral for a vendor credit card program and letters of credit related to our leases. As of January 31, 2016 and 2017 , we had restricted cash of $7.1 million and $12.7 million , respectively, which was included in other assets, non-current in the consolidated balance sheets. Marketable Securities We classify our marketable securities as available-for-sale at the time of purchase and reevaluate such classification at each balance sheet date. We may sell these securities at any time for use in current operations even if they have not yet reached maturity. As a result, we classify our securities, including those with maturities beyond twelve months, as current assets in the consolidated balance sheets. We carry these securities at fair value and record unrealized gains and losses in other comprehensive income (loss), which is reflected as a component of stockholders' equity. We evaluate our securities to assess whether those with unrealized loss positions are other than temporarily impaired. We consider impairments to be other than temporary if they are related to deterioration in credit risk or if it is likely we will sell the securities before the recovery of their cost basis. Realized gains and losses from the sale of marketable securities and declines in value deemed to be other than temporary are determined based on the specific identification method. Realized gains and losses are reported in other income (expense), net in the consolidated statements of operations. Fair Value of Financial Instruments The carrying value of our financial instruments, including cash equivalents, accounts receivable, accounts payable and accrued liabilities, approximates fair value. Accounts Receivable and Allowance Accounts receivable are recorded at the invoiced amount, and stated at realizable value, net of an allowance for doubtful accounts. Credit is extended to customers based on an evaluation of their financial condition and other factors. We generally do not require collateral or other security to support accounts receivable. We perform ongoing credit evaluations of our customers and maintain an allowance for doubtful accounts. We assess the collectability of the accounts by taking into consideration the aging of our trade receivables, historical experience, and management judgment. We write off trade receivables against the allowance when management determines a balance is uncollectible and no longer actively pursues collection of the receivable. The following table presents the changes in the allowance for doubtful accounts: Year Ended January 31, 2015 2016 2017 (in thousands) Allowance for doubtful accounts, beginning balance $ 160 $ 210 $ 944 Provision 50 918 1,394 Writeoffs — (184 ) (338 ) Allowance for doubtful accounts, ending balance $ 210 $ 944 $ 2,000 Inventory Inventory consists of finished goods and component parts, which are purchased from contract manufacturers. Product demonstration units, which we regularly sell, are the primary component of our inventories. Inventories are stated at the lower of cost or market. Cost is determined using the specific identification method for finished goods and weighted-average method for component parts. We account for excess and obsolete inventory by reducing the carrying value to the estimated net realizable value of the inventory based upon management’s assumptions about future demand and market conditions. In addition, we record a liability for firm, non-cancelable and unconditional purchase commitments with contract manufacturers and suppliers for quantities in excess of future demand forecasts consistent with excess and obsolete inventory valuations. Inventory write-offs were insignificant for the years ended January 31, 2015 , 2016 and 2017 . Property and Equipment Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization is computed using the straight-line method over the estimated useful lives of the respective assets (test equipment— 2 years , computer equipment and software— 2 to 3 years , furniture and fixtures— 7 years ). Leasehold improvements are amortized over the shorter of their estimated useful lives or the remaining lease term . Depreciation commences once the asset is placed in service. Intangible Assets Intangible assets are stated at cost, net of accumulated amortization. During the year ended January 31, 2015, we acquired certain technology patents for $9.1 million . This amount is being amortized on a straight-line basis over an estimated useful life of seven years. During the year ended January 31, 2017, we acquired certain technology patents for $1.0 million . This amount is being amortized on a straight-line basis over an estimated useful life of five years. Impairment of Long-Lived Assets We review our long-lived assets, including property and equipment, and finite-lived intangible assets for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. We measure the recoverability of these assets by comparing the carrying amounts to the future undiscounted cash flows the assets are expected to generate. If the total of the future undiscounted cash flows is less than the carrying amount of an asset, we record an impairment charge for the amount by which the carrying amount of the asset exceeds its fair market value. There have been no impairment charges recorded in any of the periods presented in the consolidated financial statements. Deferred Commissions Deferred commissions consist of direct and incremental costs paid to our sales force related to customer contracts. The deferred commission amounts are recoverable through the revenue streams that will be recognized under the related customer contracts. Direct sales commissions are deferred when earned and amortized over the same period that revenue is recognized from the related customer contract. Amortization of deferred commissions is included in sales and marketing expense in the consolidated statements of operations. As of January 31, 2016 and 2017 , we recorded deferred commissions, current, of $15.7 million and $15.8 million , respectively, and deferred commissions, non-current, of $14.3 million and $14.9 million , respectively, in other assets, non-current, in the consolidated balance sheets. During the years ended January 31, 2015 , 2016 and 2017 , we recognized sales commission expenses of $27.7 million , $47.2 million , and $84.8 million , respectively. Deferred Offering Costs Deferred offering costs, consisting of legal, accounting and filing fees directly related to our IPO, are capitalized. The deferred offering costs were offset against the IPO proceeds upon the completion of the offering. Revenue Recognition We derive revenue from two sources: (1) product revenue which includes hardware and embedded software and (2) support revenue which includes customer support, hardware maintenance and software upgrades on a when-and-if-available basis. We recognize revenue when: • Persuasive evidence of an arrangement exists —We rely upon sales agreements and/or purchase orders to determine the existence of an arrangement. • Delivery has occurred —We typically recognize product revenue upon shipment, as title and risk of loss are transferred to our channel partners at that time. Products are typically shipped directly by us to customers, and our channel partners do not stock our inventory. • The fee is fixed or determinable —We assess whether the fee is fixed or determinable based on the payment terms associated with the transaction. • Collection is reasonably assured —We assess collectability based on credit analysis and payment history. Our product revenue is derived from the sale of hardware and operating system software that is integrated into the hardware and therefore deemed essential to its functionality. The hardware and the operating system software essential to the functionality of the hardware are considered non-software deliverables and, therefore, are not subject to industry-specific software revenue recognition guidance. Support revenue is derived from the sale of maintenance and support agreements. Maintenance and support agreements include the right to receive unspecified software upgrades and enhancements on a when-and-if-available basis, bug fixes, parts replacement services related to the hardware, as well as access to our cloud-based management and support platform. Revenue related to maintenance and support agreements are recognized ratably over the contractual term, which generally range from one to five years. Costs related to maintenance and support agreements are expensed as incurred. In addition, our Evergreen Storage program provides our customers who continually maintain active maintenance and support for three years with an included controller refresh with each additional three year maintenance and support renewal. In accordance with multiple-element arrangement accounting guidance, the controller refresh represents an additional deliverable that is a separate unit of accounting and the allocated revenue is recognized in the period in which these controllers are shipped. Most of our arrangements, other than stand-alone renewals of maintenance and support agreements, are multiple-element arrangements with a combination of product and support related deliverables (as defined above). Under multiple-element arrangements, we allocate consideration at the inception of an arrangement to all deliverables based on the relative selling price method in accordance with the hierarchy provided by the multiple-element arrangement accounting guidance, which includes (i) vendor-specific objective evidence (VSOE), of selling price, if available; (ii) third-party evidence (TPE), of selling price, if VSOE is not available; and (iii) best estimate of selling price (BESP), if neither VSOE nor TPE is available. As discussed below, we allocate consideration to support related deliverables based on VSOE and to all other deliverables based on BESP as TPE typically cannot be obtained. • VSOE —We determine VSOE based on our historical pricing and discounting practices for the specific products and services when sold separately. In determining VSOE, we require that a substantial majority of the stand-alone selling prices fall within a reasonably narrow pricing range. During the three months ended October 31, 2016, we established VSOE for support related deliverables as our stand-alone selling prices are now sufficiently concentrated based on an analysis of our historical data. We have not established VSOE for any of our hardware or other deliverables. • TPE —When VSOE cannot be established for deliverables in multiple-element arrangements, we apply judgment with respect to whether we can establish a selling price based on TPE. TPE is determined based on competitor prices for interchangeable products or services when sold separately to similarly situated customers. However, because our products contain a significant element of proprietary technology and our solutions offer substantially different features and functionality, the comparable pricing of products with similar functionality typically cannot be obtained. • BESP —When neither VSOE nor TPE can be established, we utilize BESP to allocate consideration to deliverables in a multiple-element arrangement. Our process to determine BESP for products and support is based on qualitative and quantitative considerations of multiple factors, which primarily include historical sales, margin objectives and discount behavior. Additional considerations are given to other factors such as customer demographics, costs to manufacture products or provide support, pricing practices and market conditions. Deferred Revenue Deferred revenue primarily consists of amounts that have been invoiced but that have not yet been recognized as revenue and primarily consists of support. The current portion of deferred revenue represents the amounts that are expected to be recognized as revenue within one year of the consolidated balance sheet date. Warranty Costs We generally provide a three -year warranty on hardware and a 90 -day warranty on our software embedded in the hardware. Our hardware warranty provides for parts replacement for defective components and our software warranty provides for bug fixes. With respect to our hardware warranty obligation, we have a warranty agreement with our contract manufacturer under which our contract manufacturer is generally required to replace defective hardware within three years of shipment. Furthermore, our maintenance and support agreement provides for the same parts replacement that customers are entitled to under our warranty program, except that replacement parts are delivered according to targeted response times to minimize disruption to our customers’ critical business applications. Substantially all customers purchase maintenance and support agreements. Therefore, given the warranty agreement with our contract manufacturer and that substantially all our products sales are sold together with maintenance and support agreements, we generally do not have exposure related to warranty costs and no warranty reserve has been recorded. Research and Development Research and development costs are expensed as incurred. Research and development costs consist primarily of personnel costs including stock-based compensation expense, expensed prototype, to the extent there is no alternative use for that equipment, consulting services, depreciation of equipment used in research and development and allocated overhead costs. Software Development Costs We expense software development costs before technological feasibility is reached. We have determined that technological feasibility is reached shortly before the release of our products and as a result, the development costs incurred after the establishment of technological feasibility and before the release of those products have not been significant and accordingly, all software development costs have been expensed as incurred. Software development costs also include costs incurred related to our hosted applications used to deliver our support services. Capitalization begins when the preliminary project stage is complete, management with the relevant authority authorizes and commits to the funding of the software project, and it is probable the project will be completed and the software will be used to perform the intended function. Total costs related to our hosted applications incurred to date have been insignificant and as a result no software development costs were capitalized during the years ended January 31, 2015 , 2016 and 2017 . Advertising Expenses Advertising costs are expensed as incurred. Advertising expenses were $1.4 million , $6.2 million and $10.7 million for the years ended January 31, 2015 , 2016 and 2017 , respectively. Stock-Based Compensation Stock-based compensation includes restricted stock units (RSUs), stock options and purchase rights issued to employees under our ESPP. We determine the fair value of our stock options under our equity plans and purchase rights issued to employees under our ESPP on the date of grant utilizing the Black-Scholes option pricing model, which is impacted by the fair value of our common stock, as well as changes in assumptions regarding a number of subjective variables. These variables include the expected common stock price volatility over the term of the awards, the expected term of the awards, risk-free interest rates and expected dividend yield. RSUs are measured at the fair market value of the underlying stock at the grant date. We recognize stock-based compensation expense for stock-based awards on a straight-line basis over the period during which an employee is required to provide services in exchange for the award (generally the vesting period of the award). Prior to the adoption of Accounting Standards Update (ASU) No. 2016-09 (ASU 2016-09) on February 1, 2016, stock-based compensation expense was recognized only for those awards expected to vest. Subsequent to the adoption, we account for forfeitures as they occur. For stock-based awards granted to employees with a performance condition, we recognize stock-based compensation expense for these awards under the accelerated attribution method over the requisite service period when management determines it is probable that the performance condition will be satisfied. We determine the fair value of our stock options issued to non-employees on the date of grant utilizing the Black-Scholes option pricing model. Stock-based compensation expense for stock options issued to non-employees is recognized over the requisite service period or when it is probable that the performance condition will be satisfied. Options subject to vesting are periodically remeasured to current fair value over the vesting period. Income Taxes We account for income taxes using the asset and liability method. Deferred income taxes are recognized by applying enacted statutory tax rates applicable to future years to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. The measurement of deferred tax assets is reduced, if necessary, by a valuation allowance to amounts that are more likely than not to be realized. We recognize tax benefits from uncertain tax positions only if we believe that it is more likely than not that the tax position will be sustained on examination by the taxing authorities based on the technical merits of the position. The tax benefits recognized in the financial statements from such positions are then measured based on the largest benefit that has a greater than 50% likelihood of being realized upon settlement. Recently Adopted Accounting Standards In November 2015, the FASB issued ASU No. 2015-17, Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes (ASU 2015-17). ASU 2015-17 simplifies the presentation of deferred income taxes by eliminating the separate classification of deferred income tax liabilities and assets into current and non-current amounts in the consolidated balance sheets. The amendments in the update require that all deferred tax assets and liabilities be classified as non-current in the consolidated balance sheets. We early adopted this standard in the fourth quarter of fiscal 2016 on a retrospective basis. Prior periods have been retrospectively adjusted. In March 2016, the Financial Accounting Standards Board (FASB) issued ASU 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting . We elected to early adopt this standard in the second quarter of fiscal 2017 with February 1, 2016 being the effective date of adoption. ASU 2016-09 eliminates the requirement to delay the recognition of excess tax benefits until they reduce current taxes payable. Under this standard, previously unrecognized excess tax benefits shall be recognized on a modified retrospective basis. However, as of February 1, 2016, the previously unrecognized excess tax benefits of $10.5 million had no impact on our accumulated deficit balance as the related U.S. deferred tax assets were fully offset by a valuation allowance. ASU 2016-09 also requires excess tax benefits and deficiencies to be recognized prospectively in our provision for income taxes rather than additional paid-in capital. As a result of the adoption, our provision for income taxes decreased by $1.0 million during the year ended January 31, 2017. Additionally, we elected to account for forfeitures as they occur rather than estimate expected forfeiture using a modified retrospective transition method. Accordingly, we recorded a cumulative-effect adjustment of $2.1 million to accumulated deficit and an increase of stock-based compensation expense of $864,000 during the first quarter of fiscal 2017. Finally, ASU 2016-09 requires excess tax benefits to be presented as a component of operating cash flows rather than financing cash flows. We elected to adopt this requirement prospectively and accordingly, prior periods have not been adjusted. Excess tax benefits were not material for all periods presented. Recent Accounting Pronouncements Not Yet Adopted In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (ASU 2014-09), requiring an entity to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. ASU 2014-09 will supersede nearly all existing revenue recognition guidance under U.S. GAAP when it becomes effective. In August 2015, the FASB issued ASU No. 2015-14, Revenue from Contracts with Customers , deferring the effective date for ASU 2014-09 by one year. The new standard will be effective for us beginning on February 1, 2018 which is the mandatory adoption date and we do not plan to early adopt. This standard may be adopted using either the full or modified retrospective methods. We currently anticipate adopting the standard retrospectively to all prior periods presented. Our ability to apply the requirements retrospectively to all prior periods presented is dependent on system readiness, including software procured from third-party providers, and the completion of our analysis of information necessary to restate prior period financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (ASU 2016-02). ASU 2016-02 requires lessees to recognize all leases with terms in excess of one year on their balance sheet as a right-of-use asset and a lease liability at the commencement date. The new standard also simplifies the accounting for sale and leaseback transactions. The amendments in this update will be effective for us beginning on February 1, 2019 and must be adopted using a modified retrospective method for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. Early adoption is permitted. We are currently evaluating adoption methods and the impact of this standard on our consolidated financial statements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13). ASU 2016-13 amends guidance on reporting credit losses for assets held at amortized cost basis and available-for-sale debt securities to require that credit losses on available-for-sale debt securities be presented as an allowance rather than as a write-down. The measurement of credit losses for newly recognized financial assets and subsequent changes in the allowance for credit losses are recorded in the statements of operations. The amendments in this update will be effective for us beginning on February 1, 2020 with early adoption permitted on or after February 1, 2019. We are currently evaluating the impact of this standard on our consolidated financial statements. In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory (ASU 2016-16), which requires the recognition of the income tax consequences of an intra-entity transfer of an asset, other than inventory, when the transfer occurs. ASU 2016-16 will be effective for us beginning on February 1, 2018 and will be applied on a modified retrospective basis. Early adoption is permitted. We do not expect the adoption of this standard to have any impact on our consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (ASU 2016-18), which requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Therefore, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. ASU 2016-18 will be effective for us beginning on February 1, 2018 and will be applied on a retrospective basis. Early adoption is permitted. We are currently evaluating the impact of this standard on our consolidated financial statements. Reclassifications As a result of the adoption of ASU 2015-17 in the fourth quarter of fiscal 2016, we made the following reclassifications to the January 31, 2015 balance sheet: a $5.5 million decrease to deferred tax assets, non-current, a $5.8 million decrease to deferred tax liability, current, and an increase of $300,000 to deferred tax liability, non-current. |
