The financial statements include the accounts of the Company and its wholly owned subsidiaries.  All intercompany balances and transactions have been eliminated.

In July 2015,January 2016, the Financial Accounting Standards Board ("FASB") issued additional guidance regarding the recognition and measurement of financial assets and liabilities. Changes to the current GAAP model primarily affects the accounting for equity investments, financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. In addition, the FASB clarified guidance related to the valuation allowance assessment when recognizing deferred tax assets resulting from unrealized losses on available-for-sale debt securities. The Company is required to adopt the standard in the first quarter of its fiscal year ending March 31, 2019, but may elect to adopt earlier as permitted under the standard. The Company is currently evaluating what impact, if any, the adoption of this standard will have on its results of operations, financial position, and cash flows.

In July 2015, the FASB issued additional guidance regarding the subsequent measurement of inventory by requiring inventory to be measured at the lower of cost and net realizable value. The Company is required to adopt the standard in the first quarter of its fiscal year ending March 31, 2018, but may elect to adopt earlier as permitted under the standard. The adoption is not expected to have a material impact on the Company's results of operations, financial position, or cash flows.

In May 2014, the FASB issued additional guidance regarding revenue from contracts with customers. Under the new standard, revenue will be recognized at the time a good or service is transferred to a customer for the amount of consideration received for that specific good or service. Entities may use a full retrospective approach or report the cumulative effect as of the date of adoption. The Company is required to adopt the standard, as amended, in the first quarter of its fiscal year ending March 31, 2018 although, under the standard, it may adopt as early as the first quarter of its fiscal year ending March 31, 2017. The Company is currently evaluating what impact, if any, the adoption of this standard will have on its results of operations, financial position, and cash flows.

In April 2015, the FASB issued additional guidance regarding fees paid in cloud computing arrangements. The guidance requires registrants to account for fees paid in a cloud computing arrangement that includes a software license element consistent with the acquisition of other software licenses. Cloud computing arrangements without software licenses are to be accounted for as a service contract. The Company is required to adopt the standard in the first quarter of its fiscal year ending March 31, 2017. The Company is currently evaluating what impact, if any, the adoption of this standard will have on its results of operations, financial position, and cash flows.

The following tables summarize the Company’s cash and available-for-sale securities’ adjusted cost, gross unrealized gains, gross unrealized losses, and fair value by significant investment category recorded as cash and cash equivalents, short-term, or long-term investments as of September 30,December 31, 2015 and March 31, 2015 (in thousands):

There were no transfers between fair value measurement levels during the three and sixnine months ended September 30,December 31, 2015 and 2014.

In the ordinary course of business, the Company may provide indemnifications of varying scope and terms to customers, vendors, lessors, business partners, purchasers of assets or subsidiaries and other parties with respect to certain matters, including, but not limited to, losses arising out of the Company's breach of agreements or representations and warranties made by the Company, services to be provided by the Company, intellectual property infringement claims made by third parties or, with respect to the sale of assets of a subsidiary, matters related to the Company's conduct of business and tax matters prior to the sale. From time to time, the Company indemnifies customers against combinations of loss, expense, or liability arising from various triggering events relating to the sale and use of its products and services.  In addition, the Company also provides protection to customers against claims related to undiscovered liabilities, additional product liability, or environmental obligations.  In addition, the Company has entered into indemnification agreements with its directors and certain of its officers that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers of the Company. The Company maintains director and officer liability insurance, which may cover certain liabilities arising from its obligation to indemnify its directors and officers in certain circumstances. It is not possible to determine the aggregate maximum potential loss under these agreements due to the limited history of prior claims and the unique facts and circumstances involved in each particular claim. Such indemnification obligations might not be subject to maximum loss clauses. Historically, the Company has not incurred material costs as a result of obligations under these agreements and it has not accrued any liabilities related to such indemnification obligations in the condensed consolidated financial statements.

On October 12, 2012, GN Netcom, Inc. ("GN") sued Plantronics, Inc. in the United States ("U.S.") District Court for the District of Delaware, alleging violations of the Sherman Act, the Clayton Act, and Delaware common law. In its complaint, GN specifically alleges four causes of action: monopolization, attempted monopolization, concerted action in restraint of trade, and tortious interference with business relations. GN claims that the Company dominates the market for headsets sold into contact centers in the U.S. and that a critical channel for sales of headsets to contact centers is through a limited network of specialized independent distributors (“SIDs”). GN asserts that the Company attracts SIDs through exclusive distributor agreements and alleges that the use of these agreements is illegal. The Company denies each of the allegations in the complaint and is vigorously defending itself. Given the preliminary nature of the case, the Company is unable to estimate an amount or range of any reasonably possible losses resulting from these allegations.

During the quarter ended SeptemberDecember 26, 2015, 2015, GN Netcom (“GN”) indicated that it intends to bringand the Company  commenced the briefing on a motion for sanctions against Plantronics for spoliation of evidence. The briefing was concluded in early January. A court date for a hearing on the motion for sanctions has not yet been scheduled. There exists a reasonable possibility of the court issuing a sanction; however, the Company has not yet received a copy of GN’s motion or all otherany pertinent information relevant to GN’s anticipatedthe monetary amounts to be claimed by GN in their motion for sanctions.  As such, the Company cannot reasonably estimate a loss or range of losses resulting from any such sanctions, which may or may not be material to the Company’s financial condition, results of operations, or cash flows.

In addition to the specific matters discussed above, the Company is involved in various legal proceedings arising in the normal course of conducting business. For such legal proceedings, where applicable, the Company has accrued an amount that reflects the aggregate liability deemed probable and estimable, but this amount is not material to the Company's financial condition, results of operations, or cash flows. With respect to proceedings for which no accrual has been made, the Company is not able to estimate an amount or range of any reasonably possible additional losses because of the preliminary nature of many of these proceedings, the difficulty in ascertaining the applicable facts relating to many of these proceedings, the variable treatment of claims made in many of these proceedings, and the difficulty of predicting the settlement value of many of these proceedings. However, based upon the Company's historical experience, the resolution of these proceedings is not expected to have a material effect on the Company's financial condition, results of operations or cash flows. The Company may incur substantial legal fees, which are expensed as incurred, in defending against these legal proceedings.

In May 2015, Plantronics issued $500.0 million aggregate principal amount of 5.50% senior notes (the “5.50% Senior Notes”). The 5.50% Senior Notes mature on May 31, 2023, and bear interest at a rate of 5.50% per annum, payable semi-annually on May 15 and November 15 of each year, commencing on November 15, 2015. The Company received net proceeds of $488.4 million from issuance of the 5.50% Senior Notes, net of issuance costs of $11.6 million which are being amortized to interest expense over the term of the 5.50% Senior Notes using the effective interest method.

The fair value of the 5.50% Senior Notes was determined based on inputs that were observable in the market, , including the trading price of the 5.50% Senior Notes when available (Level 2). The estimated fair value and carrying value of the 5.50% Senior Notes were as follows:

The Company may redeem all or a part of the 5.50% Senior Notes, upon not less than 30 or more than a 60 day notice; however, the applicable redemption price will be determined as follows:

In addition, upon the occurrence of certain change of control triggering events, the Company may be required to repurchase the 5.50% Senior Notes, at a price equal to 101% of their principal amount, plus accrued and unpaid interest to the date of repurchase. The 5.50% Senior Notes contain restrictive covenants that, among other things, limit Plantronics' ability to create certain liens and enter into sale and leaseback transactions; create, assume, incur, or guarantee additional indebtedness of Plantronics’ subsidiaries without such subsidiary guaranteeing the 5.50% Senior Notes on an unsecured unsubordinated basis; and consolidate or merge with, or convey, transfer or lease all or substantially all of the assets of Plantronics and its subsidiaries to another person. As of September 30,December 31, 2015, the Company was in compliance with all covenants.

On May 15, 2015, the Company entered into an Amended and Restated Credit Agreement (the “Credit Agreement”) with Wells Fargo Bank, National Association (the “Bank”). The Credit Agreement amended and restated the Company’s existing Credit Agreement, dated as of May 9, 2011, by and between the Company and Bank to provide for a $100.0 million unsecured revolving credit facility. The proceeds of loans under the Credit Agreement may be used to finance stock repurchases, and for general corporate purposes.

Revolving loans under the Credit Agreement will bear interest, at the Company’s election, at (i) the Bank’s announced prime rate less 1.20% per annum or (ii) a daily one-month LIBOR rate plus 1.40% per annum. Interest is payable quarterly in arrears on the first day of each April, July, October and January, commencing July 1, 2015. Principal, together with all accrued and unpaid interest, on the revolving loans is due and payable on May 9, 2018. The Company is also obligated to pay a commitment fee of 0.37% per annum on the average daily unused amount of the revolving line of credit, which fee shall be payable quarterly in arrears on the first day of each April, July, October and January, commencing July 1, 2015.

The Company may prepay the loans and terminate the commitments under the Credit Agreement at any time, without premium or penalty, subject to the reimbursement of certain costs. As of September 30,December 31, 2015 the Company had no outstanding borrowings under the line of credit. As of March 31, 2015 the Company had $34.5 million in outstanding borrowings under the line of credit.

The Credit Agreement contains customary affirmative and negative covenants, including, among other things, covenants limiting the ability of the Company to incur debt, make capital expenditures, grant liens, merge or consolidate, and make investments. The Credit Agreement also requires the Company to comply with certain financial covenants, including (i) a maximum ratio of funded debt to EBITDA and (ii) a minimum EBITDA coverage ratio, in each case, tested as of each fiscal quarter and determined on a rolling four-quarter basis. In addition, the Company and its subsidiaries are required to maintain unrestricted cash, cash equivalents and marketable securities plus availability under the Credit Agreement at the end of each fiscal quarter of at least $300.0 million. The Credit Agreement contains customary events of default that include, among other things, payment defaults, covenant defaults, cross-defaults with certain other indebtedness, bankruptcy and insolvency defaults, and judgment defaults. The occurrence of an event of default could result in the acceleration of the obligations under the Credit Agreement. As of September 30,December 31, 2015, the Company was in compliance with all ratios and covenants.

The Company recognizes the grant-date fair value of stock-based compensation as compensation expense using the straight-line attribution approach over the service period for which the stock-based compensation is expected to vest. The following table summarizes the amount of stock-based compensation included in the condensed consolidated statements of operations:

The Company estimates the fair value of stock options and Employee Stock Purchase Plan (“ESPP”) shares using a Black-Scholes option valuation model.  At the date of grant, the Company estimated the fair value of each stock option grant and purchase right granted under the ESPP using the following weighted average assumptions:

10.11. ACCUMULATED OTHER COMPREHENSIVE INCOME

The gross fair value of our outstanding derivative contracts at the end of each period was as follows:

The effect of non-designated derivative contracts recognized in interest and other income, net in the condensed consolidated statements of operations was as follows:

The Company hedges a portion of the forecasted EUR and GBP denominated revenues with costless collars. On a monthly basis, the Company enters into option contracts with a six to eleven month term.  Collar contracts are scheduled to mature at the beginning of each fiscal quarter, at which time the instruments convert to forward contracts. The Company also enters into cash flow forwards with a three month term. Once the hedged revenues are recognized, the forward contracts become non-designated hedges to protect the resulting foreign monetary asset position for the Company. 

As of September 30,December 31, 2015, the Company had foreign currency option contracts of approximately €57.9€60.2 million and £21.1£18.8 million. As of March 31, 2015, the Company had foreign currency option contracts of approximately €67.9 million and £28.6 million. As of September 30,December 31, 2015, the Company had foreign currency forward contracts of approximately €7.0€21.6 million and £0.3£5.1 million.  As of March 31, 2015, the Company had no such instruments. The Company will reclassify all amounts accumulated in other comprehensive income into earnings within the next twelve months.

The Company hedges a portion of the forecasted Mexican Peso (“MXN”) denominated expenditures with a cross-currency swap. A loss of $3.6$2.6 million, net of tax, in AOCI as of September 30,December 31, 2015 is expected to be reclassified to cost of revenues during the next 12 months due to the recognition of the hedged forecasted expenditures. As of September 30,December 31, 2015 and March 31, 2015, the Company had foreign currency swap contracts of approximately MXN 501.3$445.1 million and MXN 431.9 million, respectively.

During the three and sixnine months ended September 30,December 31, 2015 and 2014 the Company recognized an immaterial gain on the ineffective portion of its cash flow hedges, which is reported in interest and other income (expense), net in the condensed consolidated statements of operations.

The increasedecrease in the effective tax rate for the three months ended September 30,December 31, 2015 is due primarily to a shift of income away fromlarger tax reserve releases in the lower tax rate jurisdictions partially offsetcurrent year caused by the U.S.expiration of various statutes, as well as interest expense duerelated to the 5.50% Senior Notes during the current period. The decrease in the effective tax rate for the sixnine months ended September 30,December 31, 2015 is due primarily to lower domestic earnings resulting from the interest expense on the 5.50% Senior Notes and the favorable closure of a tax audit in the current year. The effective tax rates differ from the statutory rate due primarily to the impact of foreign operations taxed at different statutory rates, tax credits, state taxes, and other factors.

On July 27, 2015, in Altera Corp. v. Commissioner, the U.S. Tax Court issued an opinion related to the treatment of stock-based compensation expense in an intercompany cost-sharing arrangement. A final decision has yet to bewas issued by the Tax Court due to other outstanding issues related toon December 1, 2015. The Internal Revenue Service may appeal the case.decision within 90 days. At this time, the U.S. Department of the Treasury has not withdrawn the requirement to include stock-based compensation in inter-company cost-sharing arrangements from its regulations. Accordingly, due to the uncertainty surrounding the status of the current regulations, questions related to the scope of potential benefits, and the risk of the Tax Court’sCourt's decision being overturned uponon appeal, the Company has not recorded any associated benefit as of September 30,the three or nine months ended December 31, 2015. The Company will continue to monitor ongoing developments and potential impacts to itsour financial statements.

Included in long-term income taxes payable in the condensed consolidated balance sheets as of September 30,December 31, 2015 and March 31, 2015 were unrecognized tax benefits of $12.5 million and $12.8 million, respectively, which would favorably impact the effective tax rate in future periods if recognized. The Company’s continuing practice is to recognize interest and/or penalties related to income tax matters in income tax expense in the condensed consolidated statements of operations.  The accrued interest related to unrecognized tax benefits was $1.9 million and $1.8 million as of September 30,December 31, 2015 and March 31, 2015, respectively.2015.  No penalties have been accrued.

The Company has effectively settled the examination by the Internal Revenue Service for its 2010 tax year. The California Franchise Tax Board completed its examination of the Company's 2007 and 2008 tax years. The Company received a Notice of Proposed Assessment and responded by filing a protest letter. The amount of the proposed assessment is not material. Foreign income tax matters for material tax jurisdictions have been concluded for tax years prior to fiscal year 2011, except in the United Kingdom where tax matters have been concluded for tax years prior to fiscal year 2014.

The Company believes that an adequate provision has been made for any adjustments that may result from tax examinations; however, the outcome of such examinations cannot be predicted with certainty. If any issues addressed in the tax examinations are resolved in a manner inconsistent with the Company's expectations, the Company could be required to adjust its provision for income tax in the period such resolution occurs. The timing of any resolution and/or closure of tax examinations is not certain.

The Company designs, manufactures, markets, and sells headsets for business and consumer applications, and other specialty products for the hearing impaired.  With respect to headsets, it makes products for use in offices and contact centers, with mobile and cordless phones, and with computers and gaming consoles.