our platform lets businesses control their digital knowledge in the cloud and sync it to more than 150 services and applications , which we refer to as our knowledge network and includes amazon alexa , apple maps , bing , cortana , facebook , google , google assistant , google maps , siri and yelp . we have established direct data integrations with applications in our knowledge network that end consumers around the globe use to discover new businesses , read reviews and find accurate answers to their queries . our cloud-based platform , the yext knowledge engine , powers all of our key features , including listings , pages and reviews , along with our other features and capabilities . we offer annual and multi-year subscriptions to our platform . subscriptions are offered in a discrete range of packages with pricing based on specified feature sets and the number of licenses managed with our platform . we sell our solution globally to customers of all sizes , through direct sales efforts to our customers , including third-party resellers , and through a self-service purchase process . in transactions with resellers , we are only party to the transaction with the reseller and are not a party to the reseller 's transaction with its customer . while the majority of our revenue is based in the u.s. , we continue to grow internationally . we offer the same services internationally as we do in the united states , and we intend to continue to pursue a strategy of expanding our international operations . our revenue from non-u.s. operations was more than 14 % of total revenue for the fiscal year ended january 31 , 2019 . our non-u.s. revenue is defined as revenue derived from contracts that are originally entered into with our non-u.s. offices , regardless of the location of the customer . we generally direct non-u.s. customer sales to our non-u.s. offices . our business has evolved in recent years . for example : in 2016 , we launched specialized integrations to our platform with applications like uber and snapchat , added our reviews feature to our platform and held our inaugural industry and customer event in new york city . in 2017 , we introduced the yext app directory , which enables businesses to connect information from systems across the business , such as workforce management systems and customer relationship management databases and held our second annual industry and customer event , onward 2017 ( formerly called `` locationworld `` ) , in november 2017 , in new york city . in 2018 , we launched a global integration with amazon to give businesses control over the answers amazon alexa provides about them and held our third annual industry and customer event , onward18 , in october 2018 , in new york city . we have experienced rapid growth in recent periods , nearly all of which has been organic growth as we have not historically conducted many acquisitions . our revenue was $ 228.3 million , $ 170.2 million and $ 124.3 million for the fiscal years ended january 31 , 2019 , 2018 and 2017 , respectively . fiscal year our fiscal year ends on january 31 st . references to fiscal 2019 , for example , are to the fiscal year ended january 31 , 2019 . components of results of operations revenue we derive our revenue primarily from subscriptions and associated support to our cloud-based knowledge engine platform . our contracts are typically one year in length , but may be up to three years or longer in length . revenue is a function of the number of customers , the number of licenses with each customer , the package to which each customer subscribes , the price of the package and renewal rates . revenue is generally recognized ratably over the contract term beginning on the commencement date of each contract , which is the date our platform is made available to customers . at the beginning of each subscription term we invoice our customers , typically in annual installments , but also monthly , quarterly , and semi-annually . amounts that have been invoiced for non-cancelable contracts are recorded in accounts receivable and in unearned revenue or revenue , depending on when the transfer of control to customers has occurred . 37 cost of revenue cost of revenue primarily relates to costs incurred in association with our cloud-based knowledge engine platform , which includes fees we pay to our knowledge network application providers . the nature of these arrangements may be unpaid , fixed , or variable . the arrangements with many of our larger providers are unpaid . as the value of our customers ' digital knowledge increases over time to our knowledge network application providers , we expect that we will be able to negotiate lower or no fee contracts and , therefore , our provider fees as a percentage of total revenue will generally decline . cost of revenue also includes expenses related to hosting our platform and associated support , which is comprised of salaries , data center capacity costs , stock-based compensation expense , benefits , and other allocated overhead costs . operating expenses sales and marketing expenses . sales and marketing expenses consist primarily of personnel and related costs , including salaries , costs of obtaining revenue contracts and stock-based compensation expense . sales and marketing expenses also consist of costs related to advertising , marketing , brand awareness activities and lead generation . research and development expenses . research and development costs are expensed as incurred . story_separator_special_tag the preparation of these financial statements requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements , as well as the reported revenue generated and expenses incurred during the reporting periods . our estimates are based on our historical experience and various other factors that we believe are reasonable under the circumstances , the results of which form the basis for making judgments about items that are not readily apparent from other sources . actual results may differ from these estimates under different assumptions or conditions . see note 2 `` summary of significant accounting policies `` to our consolidated financial statements for further discussion on our accounting policies . our most critical accounting policies and estimates , based on the degree of judgment and complexity , are discussed below . revenue recognition we derive our revenue primarily from our subscription and associated support to our cloud‑based knowledge engine platform , through contracts that are typically one year in length , but may be up to three years or longer in length . our subscriptions do not provide customers with the right to take possession of the software supporting the applications and , as a result , are accounted for as service contracts . the recognition of revenue is determined through application of the five-step model in accordance with asc 606. revenue is recognized upon transfer of control of services to our customers , including third-party resellers , in an amount that reflects the consideration we expect to receive in exchange for those services . in transactions with resellers , we contract only with the reseller , in which pricing and length of subscription and support services are agreed upon . the reseller negotiates the price charged and length of subscription and support service directly with its customer . we do not pay separate fees to third‑party resellers and do not have direct interactions with the reseller 's customer . revenue is generally recognized ratably over the contract term beginning on the commencement date of each contract , which is the date our platform is made available to our customers . amounts that have been invoiced for non-cancelable contracts are recorded in accounts receivable and in unearned revenue or revenue , depending on when the transfer of control to customers has occurred . see note 2 `` summary of significant accounting policies `` and note 3 `` revenue `` to our consolidated financial statements for further discussion on our revenue recognition . costs capitalized to obtain revenue contracts we capitalize costs to obtain revenue contracts which are incremental and recoverable , including sales commissions , certain related incentives , and associated payroll tax and fringe benefit costs . we amortize such costs on a straight-line basis over the average benefit period , which is typically three years for new contracts and one year for renewals . we determined the average benefit period having considered both qualitative and quantitative factors , most notably the estimated life of capitalized software development costs 44 resulting from additional functionality to our cloud‑based knowledge engine platform . amortization of costs capitalized to obtain revenue contracts is included in sales and marketing expense in the consolidated statements of operations and comprehensive loss . stock‑based compensation stock-based compensation for all employee stock‑based awards , including restricted stock units , restricted stock and options to purchase common stock , is measured at fair value on the date of grant and recognized over the service period . the fair value of restricted stock units and restricted stock are calculated based on the fair value of our common stock on the date of grant , while the fair value of stock options are calculated using a black‑scholes model . stock-based compensation expense is recognized over the requisite service periods of awards , which is typically four years for options and one to four years for restricted stock and restricted stock units . the estimated forfeiture rate applied is based on historical forfeiture rates . the estimated number of stock-based awards that will ultimately vest requires judgment , and to the extent actual results , or updated estimates , differ from our current estimates , such amounts will be recorded as a cumulative adjustment in the period actual results are realized or estimates are revised . a higher forfeiture rate will result in an adjustment that will decrease stock-based compensation expense , whereas a lower forfeiture rate will result in an adjustment that will increase stock-based compensation expense . our assumptions about stock price volatility are based on the average of the historical volatility for a sample of comparable companies . the expected life assumptions for employee grants are based upon the simplified method , as we do not yet have sufficient historical exercise data to provide a reasonable basis upon which to estimate our expected term due to the limited period of time our equity shares have been publicly traded . the risk-free interest rate is based on the u.s. treasury yield curve in effect at the time of grant . the dividend yield assumption is zero , because we have not historically paid any dividends and do not expect to declare or pay any dividends in the foreseeable future . we calculate the expected life assumptions for non-employees based on the remaining contractual term of the award , and plan to continue to use the contractual term upon adoption of asu 2018-07 , `` compensation - stock compensation ( topic 718 ) : improvements to non-employee share-based payment accounting , `` effective february 1 , 2019. we will continue to use judgment in evaluating the assumptions related to our stock-based compensation . as we continue to accumulate additional data related to our common stock , we may refine our estimates . if factors change and different assumptions are used , the impact to our stock-based compensation expense could

cash flows the following table summarizes our cash flows : replace_table_token_12_th 42 operating activities net cash provided by operating activities of $ 5.2 million for the fiscal year ended january 31 , 2019 was primarily due to a change in unearned revenue of $ 47.0 million and non-cash charges related to stock‑based compensation expense of $ 44.2 million , as well as a change in accounts payable , accrued expenses and other current liabilities of $ 17.3 million and non-cash charges related to depreciation and amortization expense of $ 6.8 million . these increases were partially offset by the net loss of $ 74.8 million , as well as changes in costs to obtain revenue contracts of $ 16.8 million , accounts receivable of $ 11.6 million , mainly due to timing of billing and cash collections during the period , and prepaid expenses and other current assets of $ 6.7 million . net cash used in operating activities of $ 32.4 million for the fiscal year ended january 31 , 2018 was primarily due to the net loss of $ 66.6 million , a change in accounts receivable of $ 17.0 million , mainly due to timing of billing and cash collections during the period , a change in deferred commissions of $ 4.4 million and a change in prepaid expenses and other current assets of $ 4.0 million .


 Write a concise suspicious activity report of the following text delimited by triple backquotes. Return your response as a formal report which covers the key points highlighting the location,dates,entity names and account holder information in chronological order of the text.
     ```cash flows the following table summarizes our cash flows : replace_table_token_12_th 42 operating activities net cash provided by operating activities of $ 5.2 million for the fiscal year ended january 31 , 2019 was primarily due to a change in unearned revenue of $ 47.0 million and non-cash charges related to stock‑based compensation expense of $ 44.2 million , as well as a change in accounts payable , accrued expenses and other current liabilities of $ 17.3 million and non-cash charges related to depreciation and amortization expense of $ 6.8 million . these increases were partially offset by the net loss of $ 74.8 million , as well as changes in costs to obtain revenue contracts of $ 16.8 million , accounts receivable of $ 11.6 million , mainly due to timing of billing and cash collections during the period , and prepaid expenses and other current assets of $ 6.7 million . net cash used in operating activities of $ 32.4 million for the fiscal year ended january 31 , 2018 was primarily due to the net loss of $ 66.6 million , a change in accounts receivable of $ 17.0 million , mainly due to timing of billing and cash collections during the period , a change in deferred commissions of $ 4.4 million and a change in prepaid expenses and other current assets of $ 4.0 million .
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 Suspicious Activity Report : our platform lets businesses control their digital knowledge in the cloud and sync it to more than 150 services and applications , which we refer to as our knowledge network and includes amazon alexa , apple maps , bing , cortana , facebook , google , google assistant , google maps , siri and yelp . we have established direct data integrations with applications in our knowledge network that end consumers around the globe use to discover new businesses , read reviews and find accurate answers to their queries . our cloud-based platform , the yext knowledge engine , powers all of our key features , including listings , pages and reviews , along with our other features and capabilities . we offer annual and multi-year subscriptions to our platform . subscriptions are offered in a discrete range of packages with pricing based on specified feature sets and the number of licenses managed with our platform . we sell our solution globally to customers of all sizes , through direct sales efforts to our customers , including third-party resellers , and through a self-service purchase process . in transactions with resellers , we are only party to the transaction with the reseller and are not a party to the reseller 's transaction with its customer . while the majority of our revenue is based in the u.s. , we continue to grow internationally . we offer the same services internationally as we do in the united states , and we intend to continue to pursue a strategy of expanding our international operations . our revenue from non-u.s. operations was more than 14 % of total revenue for the fiscal year ended january 31 , 2019 . our non-u.s. revenue is defined as revenue derived from contracts that are originally entered into with our non-u.s. offices , regardless of the location of the customer . we generally direct non-u.s. customer sales to our non-u.s. offices . our business has evolved in recent years . for example : in 2016 , we launched specialized integrations to our platform with applications like uber and snapchat , added our reviews feature to our platform and held our inaugural industry and customer event in new york city . in 2017 , we introduced the yext app directory , which enables businesses to connect information from systems across the business , such as workforce management systems and customer relationship management databases and held our second annual industry and customer event , onward 2017 ( formerly called `` locationworld `` ) , in november 2017 , in new york city . in 2018 , we launched a global integration with amazon to give businesses control over the answers amazon alexa provides about them and held our third annual industry and customer event , onward18 , in october 2018 , in new york city . we have experienced rapid growth in recent periods , nearly all of which has been organic growth as we have not historically conducted many acquisitions . our revenue was $ 228.3 million , $ 170.2 million and $ 124.3 million for the fiscal years ended january 31 , 2019 , 2018 and 2017 , respectively . fiscal year our fiscal year ends on january 31 st . references to fiscal 2019 , for example , are to the fiscal year ended january 31 , 2019 . components of results of operations revenue we derive our revenue primarily from subscriptions and associated support to our cloud-based knowledge engine platform . our contracts are typically one year in length , but may be up to three years or longer in length . revenue is a function of the number of customers , the number of licenses with each customer , the package to which each customer subscribes , the price of the package and renewal rates . revenue is generally recognized ratably over the contract term beginning on the commencement date of each contract , which is the date our platform is made available to customers . at the beginning of each subscription term we invoice our customers , typically in annual installments , but also monthly , quarterly , and semi-annually . amounts that have been invoiced for non-cancelable contracts are recorded in accounts receivable and in unearned revenue or revenue , depending on when the transfer of control to customers has occurred . 37 cost of revenue cost of revenue primarily relates to costs incurred in association with our cloud-based knowledge engine platform , which includes fees we pay to our knowledge network application providers . the nature of these arrangements may be unpaid , fixed , or variable . the arrangements with many of our larger providers are unpaid . as the value of our customers ' digital knowledge increases over time to our knowledge network application providers , we expect that we will be able to negotiate lower or no fee contracts and , therefore , our provider fees as a percentage of total revenue will generally decline . cost of revenue also includes expenses related to hosting our platform and associated support , which is comprised of salaries , data center capacity costs , stock-based compensation expense , benefits , and other allocated overhead costs . operating expenses sales and marketing expenses . sales and marketing expenses consist primarily of personnel and related costs , including salaries , costs of obtaining revenue contracts and stock-based compensation expense . sales and marketing expenses also consist of costs related to advertising , marketing , brand awareness activities and lead generation . research and development expenses . research and development costs are expensed as incurred . story_separator_special_tag the preparation of these financial statements requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements , as well as the reported revenue generated and expenses incurred during the reporting periods . our estimates are based on our historical experience and various other factors that we believe are reasonable under the circumstances , the results of which form the basis for making judgments about items that are not readily apparent from other sources . actual results may differ from these estimates under different assumptions or conditions . see note 2 `` summary of significant accounting policies `` to our consolidated financial statements for further discussion on our accounting policies . our most critical accounting policies and estimates , based on the degree of judgment and complexity , are discussed below . revenue recognition we derive our revenue primarily from our subscription and associated support to our cloud‑based knowledge engine platform , through contracts that are typically one year in length , but may be up to three years or longer in length . our subscriptions do not provide customers with the right to take possession of the software supporting the applications and , as a result , are accounted for as service contracts . the recognition of revenue is determined through application of the five-step model in accordance with asc 606. revenue is recognized upon transfer of control of services to our customers , including third-party resellers , in an amount that reflects the consideration we expect to receive in exchange for those services . in transactions with resellers , we contract only with the reseller , in which pricing and length of subscription and support services are agreed upon . the reseller negotiates the price charged and length of subscription and support service directly with its customer . we do not pay separate fees to third‑party resellers and do not have direct interactions with the reseller 's customer . revenue is generally recognized ratably over the contract term beginning on the commencement date of each contract , which is the date our platform is made available to our customers . amounts that have been invoiced for non-cancelable contracts are recorded in accounts receivable and in unearned revenue or revenue , depending on when the transfer of control to customers has occurred . see note 2 `` summary of significant accounting policies `` and note 3 `` revenue `` to our consolidated financial statements for further discussion on our revenue recognition . costs capitalized to obtain revenue contracts we capitalize costs to obtain revenue contracts which are incremental and recoverable , including sales commissions , certain related incentives , and associated payroll tax and fringe benefit costs . we amortize such costs on a straight-line basis over the average benefit period , which is typically three years for new contracts and one year for renewals . we determined the average benefit period having considered both qualitative and quantitative factors , most notably the estimated life of capitalized software development costs 44 resulting from additional functionality to our cloud‑based knowledge engine platform . amortization of costs capitalized to obtain revenue contracts is included in sales and marketing expense in the consolidated statements of operations and comprehensive loss . stock‑based compensation stock-based compensation for all employee stock‑based awards , including restricted stock units , restricted stock and options to purchase common stock , is measured at fair value on the date of grant and recognized over the service period . the fair value of restricted stock units and restricted stock are calculated based on the fair value of our common stock on the date of grant , while the fair value of stock options are calculated using a black‑scholes model . stock-based compensation expense is recognized over the requisite service periods of awards , which is typically four years for options and one to four years for restricted stock and restricted stock units . the estimated forfeiture rate applied is based on historical forfeiture rates . the estimated number of stock-based awards that will ultimately vest requires judgment , and to the extent actual results , or updated estimates , differ from our current estimates , such amounts will be recorded as a cumulative adjustment in the period actual results are realized or estimates are revised . a higher forfeiture rate will result in an adjustment that will decrease stock-based compensation expense , whereas a lower forfeiture rate will result in an adjustment that will increase stock-based compensation expense . our assumptions about stock price volatility are based on the average of the historical volatility for a sample of comparable companies . the expected life assumptions for employee grants are based upon the simplified method , as we do not yet have sufficient historical exercise data to provide a reasonable basis upon which to estimate our expected term due to the limited period of time our equity shares have been publicly traded . the risk-free interest rate is based on the u.s. treasury yield curve in effect at the time of grant . the dividend yield assumption is zero , because we have not historically paid any dividends and do not expect to declare or pay any dividends in the foreseeable future . we calculate the expected life assumptions for non-employees based on the remaining contractual term of the award , and plan to continue to use the contractual term upon adoption of asu 2018-07 , `` compensation - stock compensation ( topic 718 ) : improvements to non-employee share-based payment accounting , `` effective february 1 , 2019. we will continue to use judgment in evaluating the assumptions related to our stock-based compensation . as we continue to accumulate additional data related to our common stock , we may refine our estimates . if factors change and different assumptions are used , the impact to our stock-based compensation expense could

