SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
Mar. 31, 2020
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Principles of Consolidation The consolidated financial statements include the accounts of NetScout and its wholly owned subsidiaries. Inter-company transactions and balances have been eliminated in consolidation. Certain amounts for the twelve months ended March 31, 2018 have been reclassified to conform to the current period presentation. These reclassifications had no effect on the reported results of operations. Segment Reporting The Company's operating segments are determined based on the units that constitute a business for which financial information is available and for which operating results are regularly reviewed by the Chief Operating Decision Maker (CODM). The Company reports revenue and income in one reportable segment. Use of Estimates The preparation of financial statements in conformity with generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates in these financial statements include those involving revenue recognition, valuation of goodwill and acquired assets and liabilities, valuation of the pension obligation, valuation of contingent consideration and share-based compensation. These items are continuously monitored and analyzed by management for changes in facts and circumstances and material changes in these estimates could occur in the future. The Company considered the impact of the COVID-19 pandemic on the use of estimates and assumptions used for financial reporting and determined that there was no adverse material impact to its results of operations for the fourth quarter of fiscal year 2020. The full extent to which the COVID-19 pandemic will directly or indirectly impact the Company’s business, results of operations and financial condition, including sales, expenses, reserves and allowances, manufacturing, research and development costs and employee-related amounts, will depend on future developments that are highly uncertain, including as a result of new information that may emerge concerning COVID-19 and the actions taken to contain it or treat COVID-19, as well as the economic impact on local, regional, national and international customers and markets. The Company has made estimates within our financial statements and there may be changes to those estimates in future periods. Actual results may differ from these estimates. COVID-19 Risks and Uncertainties The Company is closely monitoring the impact of COVID-19 on all aspects of its business. COVID-19 was declared a global pandemic by the World Health Organization on March 11, 2020 and the President of the United States declared the COVID-19 outbreak a national emergency. While the COVID-19 pandemic has not had a material adverse impact on the Company’s operations to date, the future impacts of the pandemic and any resulting economic impact are largely unknown and rapidly evolving. It is possible that the COVID-19 pandemic, the measures taken by the governments of countries affected and the resulting economic impact may materially and adversely affect the Company’s results of operations, cash flows and financial position as well as its customers. Under Accounting Standards Update (ASU) 2014-15, Presentation of Financial Statements—Going Concern (Subtopic 205-40), or ASC 205-40, the Company has the responsibility to evaluate whether conditions and/or events raise substantial doubt about its ability to meet its future financial obligations as they become due within one year after the date that the financial statements are issued. The Company is taking precautionary actions to reduce costs and spending across the organization. This includes limiting discretionary spending and reducing hiring activities. The Company has temporarily halted the stock repurchase program, although the repurchase authorization remains effective. In addition, based on covenant levels at March 31, 2020, the Company has an incremental $285 million available under the $1.0 billion revolving credit facility. The Company expects net cash provided by operations combined with cash, cash equivalents, and marketable securities and borrowing availability under the revolving credit facility to provide sufficient liquidity to fund current obligations, capital spending, debt service requirements and working capital requirements over at least the next twelve months. Cash and Cash Equivalents and Marketable Securities Under current authoritative guidance, NetScout has classified its investments as "available-for-sale" which are carried at fair value based on quoted market prices and associated unrealized gains or losses are recorded as a separate component of stockholders’ equity until realized. NetScout considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents and those investments with original maturities greater than three months to be marketable securities. At March 31, 2020 and periodically throughout the year, NetScout has maintained cash balances in various operating accounts in excess of federally insured limits. NetScout limits the amount of credit exposure by investing only with credit worthy institutions which the Company believes are those institutions with an investment grade rating for deposits. Revenue Recognition The Company accounts for revenue in accordance with ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), which was adopted on April 1, 2018 using the modified retrospective transition method. For further discussion of the Company's accounting policies related to revenue see Note 3, "Revenue Recognition." Commission Expense Sales commissions are recorded as an asset when the initial contract's duration is longer than 12 months and amortized to expense ratably over the remaining performance periods of the related contracts. Uncollected Deferred Revenue Because of NetScout's revenue recognition policies, there are circumstances for which the Company does not recognize revenue relating to sales transactions that have been billed, but the related account receivable has not been collected. While the receivable represents an enforceable obligation, for balance sheet presentation purposes, the Company has not recognized the deferred revenue or the related account receivable and no amounts appear in the consolidated balance sheets for such transactions because control of the underlying deliverable has not transferred. The aggregate amount of unrecognized accounts receivable and deferred revenue was $11.1 million and $23.3 million at March 31, 2020 and 2019, respectively. Concentration of Credit Risk Financial instruments that potentially subject the Company to concentration of credit risk consist primarily of investments, trade accounts receivable and accounts payable. NetScout's cash, cash equivalents, and marketable securities are placed with financial institutions with high credit standings. At March 31, 2020 and 2019, the Company had no direct customers or indirect channel partners which accounted for more than 10% of the accounts receivable balance. During the fiscal years ended March 31, 2020, 2019 and 2018 respectively, no direct customers or indirect channel partners accounted for more than 10% of total revenue. Historically, the Company has not experienced any significant failure of its customers to meet their payment obligations nor does the Company anticipate material non-performance by its customers in the future; accordingly, the Company does not require collateral from its customers. However, if the Company’s assumptions are incorrect, there could be an adverse impact on its allowance for doubtful accounts. Trade Receivable Valuations Accounts receivable are stated at their net realizable value. The allowance against gross trade receivables reflects the best estimate of probable losses inherent in the receivables portfolio determined on the basis of historical experience, specific allowances for known troubled accounts and other currently available information. Inventories Inventories are stated at the lower of actual cost or net realizable value. Cost is determined by using the first-in, first-out (FIFO) method. Fixed Assets Fixed assets are stated at cost and depreciated using the straight-line method over the estimated useful lives of the assets. Leasehold improvements are amortized on a straight-line basis over the shorter of the lease term or anticipated useful life of the improvement. Gains and losses upon asset disposal are recognized in the year of disposition. Expenditures for replacements and building improvements are capitalized, while expenditures for maintenance and repairs are charged against earnings as incurred. Leases Effective April 1, 2019, the Company adopted ASU 2016-02, Leases (Topic 842), which requires leases to be recognized on the balance sheet. Leases with an original term of 12 months or less are not recognized on the Company’s balance sheet, and the lease expense related to those short-term leases is recognized over the lease term. The Company does not account for lease and non-lease (e.g. common area maintenance) components of contracts separately for any underlying asset class. For fiscal years ending prior to this date, the Company followed the guidance for leases under Topic 840, Leases. See Recently Issued Accounting Pronouncements below and Footnote 18, Leases, for further details. The Company has operating leases for administrative, research and development, sales and marketing and manufacturing facilities and equipment under various non-cancelable lease agreements. Lease commencement occurs on the date the Company takes possession or control of the property or equipment. The Company’s lease terms may include options to extend or terminate the lease where it is reasonably certain that the Company will exercise those options. The Company considers several economic factors when making this determination, including but not limited to, the significance of leasehold improvements incurred in the office space, the difficulty in replacing the asset, underlying contractual obligations, or specific characteristics unique to a particular lease. The Company’s lease agreements do not contain any material residual value guarantees or material restrictive covenants. Valuation of Goodwill, Intangible Assets and Other Acquisition and Divestiture Accounting Items The Company amortizes acquired definite-lived intangible assets over their estimated useful lives. Goodwill and other indefinite-lived intangible assets are not amortized but subject to annual impairment tests; more frequently if events or circumstances occur that would indicate a potential decline in their fair value. The Company performs the assessment annually during the fourth quarter and on an interim basis if potential impairment indicators arise. Reporting units are determined based on the components of a Company's operating segments that constitute a business for which financial information is available and for which operating results are regularly reviewed by segment management. Through the first half of fiscal year 2020, the Company had two reporting units: (1) Service Assurance and (2) Security. As part of its continued integration efforts, effective during the third quarter of fiscal year 2020, the Company reorganized its business units. As a result of this change, the Company reduced the number of reporting units from two reporting units to one reporting unit. The former Service Assurance and Security reporting units were combined as result of organizational changes made to fully integrate the resources and assets of the Service Assurance and Security business units. To test impairment, the Company first assesses qualitative factors to determine whether the existence of events and circumstances indicate that it is more likely than not that the intangible asset is impaired. If based on the Company's qualitative assessment it is more likely than not that the fair value of the intangible asset is less than its carrying amount, quantitative impairment testing is required. However, if the Company concludes otherwise, quantitative impairment testing is not required. During fiscal year 2020, the Company performed its annual impairment analysis for goodwill as of January 31, 2020. The Company performed a quantitative analysis and determined the fair value of the reporting unit's goodwill using established income and market valuation approaches. Goodwill was estimated to be recoverable as of January 31, 2020. The Company considered the current and expected future economic and market conditions surrounding the COVID-19 pandemic to be a triggering event. As such, the Company performed a quantitative analysis as of March 31, 2020 and determined the fair value of the reporting unit's goodwill using established income and market valuation approaches. Goodwill was determined to be recoverable as of March 31, 2020. Indefinite-lived intangible assets are tested for impairment at least annually, or on an interim basis if an event occurs or circumstances change that would, more likely than not, reduce the fair value of the indefinite-lived intangible assets below its carrying value. To test impairment, the Company first assesses qualitative factors to determine whether the existence of events and circumstances indicate that it is more likely than not that the indefinite-lived intangible is impaired. If based on the Company's qualitative assessment, the Company concludes that it is more likely than not that the fair value of the indefinite-lived asset is greater than its carrying amount, quantitative impairment testing is not required. The Company completed its annual impairment test of the indefinite-lived intangible asset at January 31, 2020 using the qualitative Step 0 assessment. No impairment indicators were observed as of January 31, 2020. The Company considered the current and expected future economic and market conditions surrounding the COVID-19 pandemic and concluded that it was not more likely than not that the trade name was impaired and therefore a quantitative Step 1 assessment was not performed as of March 31, 2020. The Company completed three acquisitions and one divestiture during the three-year period ended March 31, 2020. The acquisition method of accounting requires an estimate of the fair value of the assets and liabilities acquired as part of these transactions. In order to estimate the fair value of acquired intangible assets, the Company uses either an income, market or cost method approach. The Company's Level 3 liabilities at March 31, 2020 consisted of contingent purchase consideration related to the two acquisitions that occurred during the fiscal year 2020. The contingent purchase consideration related to the two acquisitions represent amounts deposited into escrow accounts, which were established to cover damages NetScout may suffer related to any liabilities that NetScout did not agree to assume or as a result of the breach of representations and warranties of the sellers as described in the acquisition agreements. The contingent purchase consideration of $0.7 million and $1.0 million related to the Gigavation Incorporated (Gigavation) and Eastwind Networks, Inc. (Eastwind) acquisitions are included as accrued other in the Company's consolidated balance sheet at March 31, 2020. Except to the extent that valid indemnification claims are made prior to such time, the $0.7 million of purchase consideration related to the Gigavation acquisition will be paid to the seller in February 2021. The contingent purchase consideration related to the Eastwind acquisition was paid to the seller in April 2020. The Company had a contingent consideration asset related to the divestiture of its handheld network test (HNT) tools business in September 2018. The contingent consideration asset represented potential future earnout payments to the Company of up to $4.0 million over two years that were contingent on the HNT tools business achieving certain milestones. The fair value of the contingent consideration of $2.3 million was recognized on the divestiture date and was measured using unobservable (Level 3) inputs. The value of the contingent consideration asset at March 31, 2020 and 2019 was $0 and $0.8 million, respectively. The Company had a contingent liability at March 31, 2018 for $0.5 million related to the acquisition of Efflux in July 2017 for which an escrow account was established to cover damages NetScout may have suffered related to any liabilities that NetScout did not agree to assume or as a result of the breach of representations and warranties of the seller as described in the acquisition agreement. The $0.5 million was paid to the seller in July 2018. The Company had a contingent liability at March 31, 2018 for $4.9 million related to the acquisition of Simena LLC in November 2011, which was based on the ultimate settlement of assets and liabilities acquired as part of the transaction, and the former owners' future period of employment with NetScout. The contingent purchase consideration of $5.0 million was paid to the seller in November 2018. Capitalized Software Development Costs Costs incurred in the research and development of the Company’s products are expensed as incurred, except for certain software development costs. Costs associated with the development of computer software are expensed prior to the establishment of technological feasibility and capitalized thereafter until the related software products are available for first customer shipment. Such costs are amortized using the straight-line method over the estimated economic life of the product, which generally does not exceed three years. Capitalized software development costs are periodically assessed for recoverability in the event of changes to the anticipated future revenue for the software products or changes in product technologies. Unamortized capitalized software development costs that are determined to be in excess of the net realizable value of the software products would be expensed in the period in which such a determination is made. Typically for accounting purposes, these R&D investments have not been capitalized because of the development methodology employed. The developments are added individually to the core code over a shorter period of time but marketed as a release once all portions are complete. Amortization included as cost of product revenue was $0.5 million, $1.1 million, and $1.0 million for the fiscal years ended March 31, 2020, 2019, and 2018, respectively. The Company capitalized $0 and $0.1 million in software development costs in the fiscal years ended March 31, 2020 and 2019. Derivative Financial Instruments Under authoritative guidance for derivative instruments and hedging activities, all hedging activities must be documented at the inception of the hedge and must meet the definition of highly effective in offsetting changes to future cash flows in order for the derivative to qualify for hedge accounting. Under the guidance, if an instrument qualifies for hedge accounting, the changes in the fair value each period for open contracts, measured at the end of the period, are recorded to other comprehensive income. Otherwise, changes in the fair value are recorded in earnings each period. Management must perform initial and ongoing tests in order to qualify for hedge accounting. In accordance with the guidance, the Company accounts for its instruments under hedge accounting. The effectiveness and a measurement of ineffectiveness of qualifying hedge contracts are assessed by the Company quarterly. The Company records the fair value of its derivatives in prepaid expenses and other current assets and accrued other in the Company's consolidated balance sheet. The effective portion of gains or losses resulting from changes in the fair value of qualifying hedges are recorded in other comprehensive income (loss) until the forecasted transaction occurs, with any ineffective portion classified directly to the Company’s consolidated statement of operations based on the expense categories of the items being hedged. When forecasted transactions occur, unrealized gains or losses associated with the effective portion of the hedge are reclassified to the respective expense categories in the Company’s consolidated statement of operations. Gains or losses related to hedging activity are included as operating activities in the Company’s consolidated statement of cash flows. If the underlying forecasted transactions do not occur, or it becomes probable that they will not occur, the gain or loss on the related cash flow hedge is recognized immediately in earnings. Contingencies NetScout accounts for claims and contingencies in accordance with authoritative guidance that requires an estimated loss to be recorded from a claim or loss contingency when information available prior to issuance of its consolidated financial statements indicates that it is probable that a liability has been incurred at the date of the consolidated financial statements and the amount of the loss can be reasonably estimated. If NetScout determines that it is reasonably possible but not probable that an asset has been impaired or a liability has been incurred or if the amount of a probable loss cannot be reasonably estimated, then in accordance with the authoritative guidance, Netscout discloses the amount or range of estimated loss if the amount or range of estimated loss is material. Accounting for claims and contingencies requires NetScout to use its judgment. NetScout consults with legal counsel on those issues related to litigation and seeks input from other experts and advisors with respect to matters in the ordinary course of business. Contingent assets and liabilities include contingent consideration in connection with the Company’s acquisitions and divestitures. Contingent consideration represents earnout payments in connection with the Company’s acquisitions and divestitures and is recognized at fair value on the acquisition date and remeasured each reporting period with subsequent adjustments recognized in the consolidated statements of income. The Company discounts the contingent purchase consideration to present value using a risk adjusted interest rate at each reporting period. Contingent consideration is valued using significant inputs that are not observable in the market which are defined as Level 3 inputs pursuant to fair value measurement accounting. The Company believes its estimates and assumptions are reasonable, however, there is significant judgment involved. Changes in the fair value of contingent assets and liabilities may result from changes in discount periods. The Company reflects changes in fair value due to probability changes in earnings in the consolidated statements of income. Earnout payments are reflected in both cash flows from operating and financing activities and the changes in fair value are reflected in cash flows from operating activities in the consolidated statements of cash flows. Share-Based Compensation NetScout recognizes compensation expense for all share-based payments granted. Under the fair value recognition provisions, share-based compensation is calculated net of an estimated forfeiture rate and compensation cost is only recognized for those shares expected to vest on a straight-line basis over the expected requisite service period of the award. Foreign Currency NetScout accounts for its reporting of foreign operations in accordance with guidance which establishes guidelines for the determination of the functional currency of foreign subsidiaries. In accordance with the guidance, NetScout has determined its functional currency for those foreign subsidiaries that are an extension of NetScout's U.S. operations to be the U.S. Dollar. Assets and liabilities of subsidiaries operating outside the United States with a functional currency other than U.S. dollars are translated into U.S. dollars using the period-end exchange rate, and income and expense items are translated using the average exchange rate during the period. Cumulative translation adjustments are reflected as a separate component of stockholders' equity. NetScout will experience currency exchange risk with respect to foreign currency denominated expenses. In order to partially offset the risks associated with the effects of certain foreign currency exposures, NetScout has established a program that utilizes foreign currency forward contracts. Under this program, increases or decreases in foreign currency exposures are partially offset by gains or losses on forward contracts, to mitigate the impact of foreign currency transaction gains or losses. The Company does not use forward contracts to engage in currency speculation. All outstanding foreign currency forward contracts are recorded at fair value at the end of each fiscal period. The Company had foreign currency losses of $0.7 million, $2.0 million and $4.1 million for the fiscal years ended March 31, 2020, 2019 and 2018, respectively. These amounts are included in other expense, net. Advertising Expense NetScout recognizes advertising expense as incurred. Advertising expense was $8.3 million, $9.4 million and $6.5 million for the fiscal years ended March 31, 2020, 2019 and 2018, respectively. Comprehensive Income (Loss) Comprehensive income (loss) consists of net income (loss) and other comprehensive income (loss). Other comprehensive income (loss) typically consists of unrealized gains and losses on marketable securities, unrealized gain (loss) on hedge contracts, actuarial gains and losses, and foreign currency translation adjustments. Income Taxes NetScout accounts for its income taxes under the asset and liability method. Under the asset and liability method, deferred tax assets and liabilities are recognized based on anticipated future tax consequences attributable to differences between financial statement carrying amounts of assets and liabilities and their respective tax basis, as well as the effect of any net operating loss and tax credit carryforwards. Income tax expense is comprised of the current tax liability or benefit and the change in deferred tax assets and liabilities. NetScout evaluates the recoverability of deferred tax assets by considering all positive and negative evidence relating to future profitability. NetScout weighs objective and verifiable evidence more heavily in this analysis. In situations where NetScout concludes that it does not have sufficient objective and verifiable evidence to support the realizability of the deferred tax asset, NetScout creates a valuation allowance against it. Recent Accounting Standards In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. The amendments provide optional guidance for a limited time to ease the potential burden in accounting for reference rate reform. The new guidance provides optional expedients and exceptions for applying U.S. GAAP to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. The amendments apply only to contracts and hedging relationships that reference LIBOR or another reference rate expected to be discontinued due to reference rate reform. These amendments are effective immediately and may be applied prospectively to contract modifications made and hedging relationships entered into or evaluated on or before December 31, 2022. The adoption will not have a material impact on the Company's financial position, results of operations, and disclosures. In January 2020, the FASB issued ASU 2020-01, Investments-Equity Securities (Topic 321), Investments-Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815) - Clarifying the Interactions between Topic 321, Topic 323, and Topic 815. This guidance addresses accounting for the transition into and out of the equity method and provides clarification of the interaction of rules for equity securities, the equity method of accounting, and forward contracts and purchase options on certain types of securities. This standard is effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2020. Early adoption is permitted. ASU 2020-01 is effective for NetScout beginning April 1, 2021. The Company is currently assessing the effect that ASU 2020-01 will have on its financial position, results of operations, and disclosures. In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes. ASU 2019-12 simplifies the accounting for income taxes, eliminates certain exceptions within ASC 740, Income Taxes, and clarifies certain aspects of the current guidance to promote consistency among reporting entities. ASU 2019-12 is effective for fiscal years beginning after December 15, 2021. ASU 2019-12 is effective for NetScout beginning April 1, 2022. Most amendments within the standard are required to be applied on a prospective basis, while certain amendments must be applied on a retrospective or modified retrospective basis. The Company is currently assessing the effect that ASU 2019-12 will have on its financial position, results of operations, and disclosures. In August 2018, the FASB issued ASU 2018-14, Compensation – Retirement Benefits – Defined Benefit Plans – General (Subtopic 715-20): Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans. This ASU adds, modifies and clarifies several disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. This guidance is effective for fiscal years ending after December 15, 2020. ASU 2018-14 is effective for NetScout beginning April 1, 2020. Early adoption is permitted. This guidance will have no impact on the Company's consolidated financials statements upon adoption other than with respect to the updated disclosure requirements. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement. ASU 2018-13 adds, modifies and removes several disclosure requirements relative to the three levels of inputs used to measure fair value in accordance with Topic 820, Fair Value Measurement. This guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within that fiscal year. ASU 2018-13 is effective for NetScout beginning April 1, 2020. Early adoption is permitted. The Company does not believe the adoption of ASU 2018-13 will have a material impact on its financial position, results of operations, and disclosures. In August 2017, the FASB issued ASU 2017-12, Derivatives and Hedging (Topic 815), Targeted Improvements to Accounting for Hedging Activities (ASU 2017-12). ASU 2017-12 provides guidance to better align an entity's risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results. The amendments expand and refine hedge accounting for both non-financial and financial risk components and align the recognition and presentation of the effects of the hedging instrument and the hedged item in the financial statements. This standard is effective for financial statements issued for fiscal years beginning after December 15, 2018. The Company adopted ASU 2017-12 effective April 1, 2019. The adoption has had an immaterial impact on the Company's consolidated financial statements. In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13) and also issued subsequent amendments to the initial guidance: ASU 2018-19, ASU 2019-04, ASU 2019-05, ASU 2019-11 and ASU 2020-02 (collectively, Topic 326). Topic 326 requires measurement and recognition of expected credit losses for financial assets held. Topic 326 replaces the existing incurred loss impairment model with an expected loss methodology, which will result in more timely recognition of credit losses. Topic 326 is effective for annual periods beginning after December 15, 2019, and interim periods therein. Topic 326 is effective for NetScout beginning April 1, 2020, and earlier adoption is permitted. The Company does not believe the adoption of Topic 326 will have a material impact on its financial position, results of operations, and disclosures. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) Section A - Leases: Amendments to the FASB Accounting Standards Codification (ASU 2016-02) and issued subsequent amendments to initial guidance in July 2018 within ASU 2018-10, Codification Improvements to Topic 842, Leases and ASU 2018-11, Leases (Topic 842): Targeted Improvements (collectively, ASC 842). ASC 842 aims to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. The Company adopted the guidance as of April 1, 2019 using the modified retrospective method. Please refer to Note 18, "Leases" for further details.

The preparation of financial statements in conformity with generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates in these financial statements include those involving revenue recognition, valuation of goodwill and acquired assets and liabilities, valuation of the pension obligation, valuation of contingent consideration and share-based compensation. These items are continuously monitored and analyzed by management for changes in facts and circumstances and material changes in these estimates could occur in the future.

The Company considered the impact of the COVID-19 pandemic on the use of estimates and assumptions used for financial reporting and determined that there was no adverse material impact to its results of operations for the fourth quarter of fiscal year 2020. The full extent to which the COVID-19 pandemic will directly or indirectly impact the Company’s business, results of operations and financial condition, including sales, expenses, reserves and allowances, manufacturing, research and development costs and employee-related amounts, will depend on future developments that are highly uncertain, including as a result of new information that may emerge concerning COVID-19 and the actions taken to contain it or treat COVID-19, as well as the economic impact on local, regional, national and international customers and markets. The Company has made estimates within our financial statements and there may be changes to those estimates in future periods. Actual results may differ from these estimates.

The Company is closely monitoring the impact of COVID-19 on all aspects of its business. COVID-19 was declared a global pandemic by the World Health Organization on March 11, 2020 and the President of the United States declared the COVID-19 outbreak a national emergency. While the COVID-19 pandemic has not had a material adverse impact on the Company’s operations to date, the future impacts of the pandemic and any resulting economic impact are largely unknown and rapidly evolving. It is possible that the COVID-19 pandemic, the measures taken by the governments of countries affected and the resulting economic impact may materially and adversely affect the Company’s results of operations, cash flows and financial position as well as its customers.

doubt about its ability to meet its future financial obligations as they become due within one year after the date that the financial statements are issued. The Company is taking precautionary actions to reduce costs and spending across the organization. This includes limiting discretionary spending and reducing hiring activities. The Company has temporarily halted the stock repurchase program, although the repurchase authorization remains effective. In addition, based on covenant levels at March 31, 2020, the Company has an incremental $285 million available under the $1.0 billion revolving credit facility. The Company expects net cash provided by operations combined with cash, cash equivalents, and marketable securities and borrowing availability under the revolving credit facility to provide sufficient liquidity to fund current obligations, capital spending, debt service requirements and working capital requirements over at least the next twelve months.

Under current authoritative guidance, NetScout has classified its investments as "available-for-sale" which are carried at fair value based on quoted market prices and associated unrealized gains or losses are recorded as a separate component of stockholders’ equity until realized. NetScout considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents and those investments with original maturities greater than three months to be marketable securities.

Because of NetScout's revenue recognition policies, there are circumstances for which the Company does not recognize revenue relating to sales transactions that have been billed, but the related account receivable has not been collected. While the receivable represents an enforceable obligation, for balance sheet presentation purposes, the Company has not recognized the deferred revenue or the related account receivable and no amounts appear in the consolidated balance sheets for such transactions because control of the underlying deliverable has not transferred. The aggregate amount of unrecognized accounts receivable and deferred revenue was $11.1 million and $23.3 million at March 31, 2020 and 2019, respectively.

Historically, the Company has not experienced any significant failure of its customers to meet their payment obligations nor does the Company anticipate material non-performance by its customers in the future; accordingly, the Company does not require collateral from its customers. However, if the Company’s assumptions are incorrect, there could be an adverse impact on its allowance for doubtful accounts.

Fixed assets are stated at cost and depreciated using the straight-line method over the estimated useful lives of the assets. Leasehold improvements are amortized on a straight-line basis over the shorter of the lease term or anticipated useful life of the improvement. Gains and losses upon asset disposal are recognized in the year of disposition. Expenditures for replacements and building improvements are capitalized, while expenditures for maintenance and repairs are charged against earnings as incurred.

Effective April 1, 2019, the Company adopted ASU 2016-02, Leases (Topic 842), which requires leases to be recognized on the balance sheet. Leases with an original term of 12 months or less are not recognized on the Company’s balance sheet, and the lease expense related to those short-term leases is recognized over the lease term. The Company does not account for lease and non-lease (e.g. common area maintenance) components of contracts separately for any underlying asset class. For fiscal years ending prior to this date, the Company followed the guidance for leases under Topic 840, Leases. See Recently Issued Accounting Pronouncements below and Footnote 18, Leases, for further details.

The Company has operating leases for administrative, research and development, sales and marketing and manufacturing facilities and equipment under various non-cancelable lease agreements. Lease commencement occurs on the date the Company takes possession or control of the property or equipment. The Company’s lease terms may include options to extend or terminate the lease where it is reasonably certain that the Company will exercise those options. The Company considers several economic factors when making this determination, including but not limited to, the significance of leasehold improvements incurred in the office space, the difficulty in replacing the asset, underlying contractual obligations, or specific characteristics unique to a particular lease. The Company’s lease agreements do not contain any material residual value guarantees or material restrictive covenants.

The Company amortizes acquired definite-lived intangible assets over their estimated useful lives. Goodwill and other indefinite-lived intangible assets are not amortized but subject to annual impairment tests; more frequently if events or circumstances occur that would indicate a potential decline in their fair value. The Company performs the assessment annually during the fourth quarter and on an interim basis if potential impairment indicators arise.

Reporting units are determined based on the components of a Company's operating segments that constitute a business for which financial information is available and for which operating results are regularly reviewed by segment management. Through the first half of fiscal year 2020, the Company had two reporting units: (1) Service Assurance and (2) Security. As part of its continued integration efforts, effective during the third quarter of fiscal year 2020, the Company reorganized its business units. As a result of this change, the Company reduced the number of reporting units from two reporting units to one reporting unit. The former Service Assurance and Security reporting units were combined as result of organizational changes made to fully integrate the resources and assets of the Service Assurance and Security business units.

To test impairment, the Company first assesses qualitative factors to determine whether the existence of events and circumstances indicate that it is more likely than not that the intangible asset is impaired. If based on the Company's qualitative assessment it is more likely than not that the fair value of the intangible asset is less than its carrying amount, quantitative impairment testing is required. However, if the Company concludes otherwise, quantitative impairment testing is not required. During fiscal year 2020, the Company performed its annual impairment analysis for goodwill as of January 31, 2020. The Company performed a quantitative analysis and determined the fair value of the reporting unit's goodwill using established income and market valuation approaches. Goodwill was estimated to be recoverable as of January 31, 2020. The Company considered the current and expected future economic and market conditions surrounding the COVID-19 pandemic to be a

Indefinite-lived intangible assets are tested for impairment at least annually, or on an interim basis if an event occurs or circumstances change that would, more likely than not, reduce the fair value of the indefinite-lived intangible assets below its carrying value. To test impairment, the Company first assesses qualitative factors to determine whether the existence of events and circumstances indicate that it is more likely than not that the indefinite-lived intangible is impaired. If based on the Company's qualitative assessment, the Company concludes that it is more likely than not that the fair value of the indefinite-lived asset is greater than its carrying amount, quantitative impairment testing is not required. The Company completed its annual impairment test of the indefinite-lived intangible asset at January 31, 2020 using the qualitative Step 0 assessment. No impairment indicators were observed as of January 31, 2020. The Company considered the current and expected future economic and market conditions surrounding the COVID-19 pandemic and concluded that it was not more likely than not that the trade name was impaired and therefore a quantitative Step 1 assessment was not performed as of March 31, 2020.

The Company's Level 3 liabilities at March 31, 2020 consisted of contingent purchase consideration related to the two acquisitions that occurred during the fiscal year 2020. The contingent purchase consideration related to the two acquisitions represent amounts deposited into escrow accounts, which were established to cover damages NetScout may suffer related to any liabilities that NetScout did not agree to assume or as a result of the breach of representations and warranties of the sellers as described in the acquisition agreements. The contingent purchase consideration of $0.7 million and $1.0 million related to the Gigavation Incorporated (Gigavation) and Eastwind Networks, Inc. (Eastwind) acquisitions are included as accrued other in the Company's consolidated balance sheet at March 31, 2020. Except to the extent that valid indemnification claims are made prior to such time, the $0.7 million of purchase consideration related to the Gigavation acquisition will be paid to the seller in February 2021. The contingent purchase consideration related to the Eastwind acquisition was paid to the seller in April 2020.

The Company had a contingent consideration asset related to the divestiture of its handheld network test (HNT) tools business in September 2018. The contingent consideration asset represented potential future earnout payments to the Company of up to $4.0 million over two years that were contingent on the HNT tools business achieving certain milestones. The fair value of the contingent consideration of $2.3 million was recognized on the divestiture date and was measured using unobservable (Level 3) inputs. The value of the contingent consideration asset at March 31, 2020 and 2019 was $0 and $0.8 million, respectively.

The Company had a contingent liability at March 31, 2018 for $0.5 million related to the acquisition of Efflux in July 2017 for which an escrow account was established to cover damages NetScout may have suffered related to any liabilities that NetScout did not agree to assume or as a result of the breach of representations and warranties of the seller as described in the acquisition agreement. The $0.5 million was paid to the seller in July 2018.

The Company had a contingent liability at March 31, 2018 for $4.9 million related to the acquisition of Simena LLC in November 2011, which was based on the ultimate settlement of assets and liabilities acquired as part of the transaction, and the former owners' future period of employment with NetScout. The contingent purchase consideration of $5.0 million was paid to the seller in November 2018.

Costs incurred in the research and development of the Company’s products are expensed as incurred, except for certain software development costs. Costs associated with the development of computer software are expensed prior to the establishment of technological feasibility and capitalized thereafter until the related software products are available for first customer shipment. Such costs are amortized using the straight-line method over the estimated economic life of the product, which generally does not exceed three years. Capitalized software development costs are periodically assessed for recoverability in the event of changes to the anticipated future revenue for the software products or changes in product technologies. Unamortized capitalized software development costs that are determined to be in excess of the net realizable value of the software products would be expensed in the period in which such a determination is made.

Under authoritative guidance for derivative instruments and hedging activities, all hedging activities must be documented at the inception of the hedge and must meet the definition of highly effective in offsetting changes to future cash flows in order for the derivative to qualify for hedge accounting. Under the guidance, if an instrument qualifies for hedge accounting, the changes in the fair value each period for open contracts, measured at the end of the period, are recorded to other comprehensive income. Otherwise, changes in the fair value are recorded in earnings each period. Management must perform initial and ongoing tests in order to qualify for hedge accounting. In accordance with the guidance, the Company accounts for its instruments under hedge accounting. The effectiveness and a measurement of ineffectiveness of qualifying hedge contracts are assessed by the Company quarterly. The Company records the fair value of its derivatives in prepaid expenses and other current assets and accrued other in the Company's consolidated balance sheet. The effective portion of gains or losses resulting from changes in the fair value of qualifying hedges are recorded in other comprehensive income (loss) until the forecasted transaction occurs, with any ineffective portion classified directly to the Company’s consolidated statement of operations based on the expense categories of the items being hedged. When forecasted transactions occur, unrealized gains or losses associated with the effective portion of the hedge are reclassified to the respective expense categories in the Company’s consolidated statement of operations. Gains or losses related to hedging activity are included as operating activities in the Company’s consolidated statement of cash flows. If the underlying forecasted transactions do not occur, or it becomes probable that they will not occur, the gain or loss on the related cash flow hedge is recognized immediately in earnings.

NetScout accounts for claims and contingencies in accordance with authoritative guidance that requires an estimated loss to be recorded from a claim or loss contingency when information available prior to issuance of its consolidated financial statements indicates that it is probable that a liability has been incurred at the date of the consolidated financial statements and the amount of the loss can be reasonably estimated. If NetScout determines that it is reasonably possible but not probable that an asset has been impaired or a liability has been incurred or if the amount of a probable loss cannot be reasonably estimated, then in accordance with the authoritative guidance, Netscout discloses the amount or range of estimated loss if the amount or range of estimated loss is material. Accounting for claims and contingencies requires NetScout to use its judgment. NetScout consults with legal counsel on those issues related to litigation and seeks input from other experts and advisors with respect to matters in the ordinary course of business.

Contingent assets and liabilities include contingent consideration in connection with the Company’s acquisitions and divestitures. Contingent consideration represents earnout payments in connection with the Company’s acquisitions and divestitures and is recognized at fair value on the acquisition date and remeasured each reporting period with subsequent adjustments recognized in the consolidated statements of income. The Company discounts the contingent purchase consideration to present value using a risk adjusted interest rate at each reporting period. Contingent consideration is valued using significant inputs that are not observable in the market which are defined as Level 3 inputs pursuant to fair value measurement accounting. The Company believes its estimates and assumptions are reasonable, however, there is significant judgment involved.

Changes in the fair value of contingent assets and liabilities may result from changes in discount periods. The Company reflects changes in fair value due to probability changes in earnings in the consolidated statements of income. Earnout payments are reflected in both cash flows from operating and financing activities and the changes in fair value are reflected in cash flows from operating activities in the consolidated statements of cash flows.

NetScout will experience currency exchange risk with respect to foreign currency denominated expenses. In order to partially offset the risks associated with the effects of certain foreign currency exposures, NetScout has established a program that utilizes foreign currency forward contracts. Under this program, increases or decreases in foreign currency exposures are partially offset by gains or losses on forward contracts, to mitigate the impact of foreign currency transaction gains or losses. The Company does not use forward contracts to engage in currency speculation. All outstanding foreign currency forward contracts are recorded at fair value at the end of each fiscal period.

NetScout accounts for its income taxes under the asset and liability method. Under the asset and liability method, deferred tax assets and liabilities are recognized based on anticipated future tax consequences attributable to differences between financial statement carrying amounts of assets and liabilities and their respective tax basis, as well as the effect of any net operating loss and tax credit carryforwards. Income tax expense is comprised of the current tax liability or benefit and the change in deferred tax assets and liabilities. NetScout evaluates the recoverability of deferred tax assets by considering all positive and negative evidence relating to future profitability. NetScout weighs objective and verifiable evidence more heavily in this analysis. In situations where NetScout concludes that it does not have sufficient objective and verifiable evidence to support the realizability of the deferred tax asset, NetScout creates a valuation allowance against it.

In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. The amendments provide optional guidance for a limited time to ease the potential burden in accounting for reference rate reform. The new guidance provides optional expedients and exceptions for applying U.S. GAAP to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. The amendments apply only to contracts and hedging relationships that reference LIBOR or another reference rate expected to be discontinued due to reference rate reform. These amendments are effective immediately and may be applied prospectively to contract modifications made and hedging relationships entered into or evaluated on or before December 31, 2022. The adoption will not have a material impact on the Company's financial position, results of operations, and disclosures.

In January 2020, the FASB issued ASU 2020-01, Investments-Equity Securities (Topic 321), Investments-Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815) - Clarifying the Interactions between Topic 321, Topic 323, and Topic 815. This guidance addresses accounting for the transition into and out of the equity method and provides clarification of the interaction of rules for equity securities, the equity method of accounting, and forward contracts and purchase options on certain types of securities. This standard is effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2020. Early adoption is permitted. ASU 2020-01 is effective for NetScout beginning April

In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes. ASU 2019-12 simplifies the accounting for income taxes, eliminates certain exceptions within ASC 740, Income Taxes, and clarifies certain aspects of the current guidance to promote consistency among reporting entities. ASU 2019-12 is effective for fiscal years beginning after December 15, 2021. ASU 2019-12 is effective for NetScout beginning April 1, 2022. Most amendments within the standard are required to be applied on a prospective basis, while certain amendments must be applied on a retrospective or modified retrospective basis. The Company is currently assessing the effect that ASU 2019-12 will have on its financial position, results of operations, and disclosures.

In August 2018, the FASB issued ASU 2018-14, Compensation – Retirement Benefits – Defined Benefit Plans – General (Subtopic 715-20): Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans. This ASU adds, modifies and clarifies several disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. This guidance is effective for fiscal years ending after December 15, 2020. ASU 2018-14 is effective for NetScout beginning April 1, 2020. Early adoption is permitted. This guidance will have no impact on the Company's consolidated financials statements upon adoption other than with respect to the updated disclosure requirements.

In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement. ASU 2018-13 adds, modifies and removes several disclosure requirements relative to the three levels of inputs used to measure fair value in accordance with Topic 820, Fair Value Measurement. This guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within that fiscal year. ASU 2018-13 is effective for NetScout beginning April 1, 2020. Early adoption is permitted. The Company does not believe the adoption of ASU 2018-13 will have a material impact on its financial position, results of operations, and disclosures.

In August 2017, the FASB issued ASU 2017-12, Derivatives and Hedging (Topic 815), Targeted Improvements to Accounting for Hedging Activities (ASU 2017-12). ASU 2017-12 provides guidance to better align an entity's risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results. The amendments expand and refine hedge accounting for both non-financial and financial risk components and align the recognition and presentation of the effects of the hedging instrument and the hedged item in the financial statements. This standard is effective for financial statements issued for fiscal years beginning after December 15, 2018. The Company adopted ASU 2017-12 effective April 1, 2019. The adoption has had an immaterial impact on the Company's consolidated financial statements.

In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13) and also issued subsequent amendments to the initial guidance: ASU 2018-19, ASU 2019-04, ASU 2019-05, ASU 2019-11 and ASU 2020-02 (collectively, Topic 326). Topic 326 requires measurement and recognition of expected credit losses for financial assets held. Topic 326 replaces the existing incurred loss impairment model with an expected loss methodology, which will result in more timely recognition of credit losses. Topic 326 is effective for annual periods beginning after December 15, 2019, and interim periods therein. Topic 326 is effective for NetScout beginning April 1, 2020, and earlier adoption is permitted. The Company does not believe the adoption of Topic 326 will have a material impact on its financial position, results of operations, and disclosures.

In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) Section A - Leases: Amendments to the FASB Accounting Standards Codification (ASU 2016-02) and issued subsequent amendments to initial guidance in July 2018 within ASU 2018-10, Codification Improvements to Topic 842, Leases and ASU 2018-11, Leases (Topic 842): Targeted Improvements (collectively, ASC 842). ASC 842 aims to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. The Company adopted the guidance as of April 1, 2019 using the modified retrospective method. Please refer to Note 18, "Leases" for further details.