Plantronics (POLY) 10-Q 31 Oct 17 2018 Q2 Quarterly report Financial data

DOCUMENT AND ENTITY INFORMATION

DOCUMENT AND ENTITY INFORMATION - shares	6 Months Ended
	Sep. 30, 2017	Oct. 27, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	PLANTRONICS INC /CA/
Entity Central Index Key	914,025
Current Fiscal Year End Date	--03-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding		33,066,132

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2017	Mar. 31, 2017
Current assets:
Cash and cash equivalents	$ 303,116	$ 301,970
Short-term investments	197,278	178,179
Accounts receivable, net	139,683	141,177
Inventory, net	60,999	55,456
Other current assets	33,310	22,195
Total current assets	734,386	698,977
Long-term investments	105,251	127,176
Property, plant, and equipment, net	146,830	150,307
Goodwill and purchased intangibles, net	15,498	15,577
Deferred tax and other assets	20,417	25,122
Total assets	1,022,382	1,017,159
Current liabilities:
Accounts payable	45,619	42,885
Accrued liabilities	68,434	74,285
Total current liabilities	114,053	117,170
Long term debt, net of issuance costs	491,784	491,059
Long-term income taxes payable	11,997	11,729
Other long-term liabilities	16,881	15,045
Total liabilities	634,715	635,003
Commitments and contingencies (Note 6)
Stockholders' equity:
Common stock	813	804
Additional paid-in capital	848,729	818,777
Accumulated other comprehensive income	1,531	4,694
Retained earnings	348,655	319,931
Total stockholders' equity before treasury stock	1,199,728	1,144,206
Less: Treasury stock, at cost	(812,061)	(762,050)
Total stockholders' equity	387,667	382,156
Total liabilities and stockholders' equity	$ 1,022,382	$ 1,017,159

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Net revenues	$ 210,300	$ 216,183	$ 414,226	$ 439,289
Cost of revenues	102,668	105,737	203,311	215,770
Gross profit	107,632	110,446	210,915	223,519
Operating expenses:
Research, development, and engineering	19,932	22,379	41,145	44,723
Selling, general, and administrative	57,696	56,875	113,929	112,662
(Gain) loss, net from litigation settlements	(104)	(349)	(280)	4,390
Restructuring and other related charges (credits)	(51)	(415)	2,522	(1,463)
Total operating expenses	77,473	78,490	157,316	160,312
Operating income	30,159	31,956	53,599	63,207
Interest expense	(7,260)	(7,257)	(14,563)	(14,545)
Other non-operating income and (expense), net	1,826	1,340	2,740	3,692
Income before income taxes	24,725	26,039	41,776	52,354
Income tax expense	4,772	5,565	2,995	11,493
Net income	$ 19,953	$ 20,474	$ 38,781	$ 40,861
Earnings per common share:
Basic (in dollars per share)	$ 0.59	$ 0.63	$ 1.16	$ 1.27
Diluted (in dollars per share)	$ 0.59	$ 0.63	$ 1.14	$ 1.24
Shares used in computing basic earnings per common share	32,570	32,281	32,538	32,269
Shares used in computing diluted earnings per common share	32,809	32,726	33,111	32,865
Cash dividends declared per common share (in dollars per share)	$ 0.15	$ 0.15	$ 0.3	$ 0.3

CONDENSED CONSOLIDATED STATEME4

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 19,953	$ 20,474	$ 38,781	$ 40,861
Other comprehensive income (loss):
Foreign currency translation adjustments	57	4	257	(250)
Unrealized gains (losses) on cash flow hedges:
Unrealized cash flow hedge gains (losses) arising during the period	(2,302)	(650)	(4,647)	304
Net (gains) losses reclassified into income for revenue hedges	1,131	(825)	1,149	(985)
Net (gains) losses reclassified into income for cost of revenue hedges	(174)	589	(132)	1,316
Net unrealized gains (losses) on cash flow hedges	(1,345)	(886)	(3,630)	635
Unrealized holding gains (losses) during the period	133	(272)	209	42
Aggregate income tax benefit (expense) of the above items	(19)	98	1	(26)
Other comprehensive income (loss)	(1,174)	(1,056)	(3,163)	401
Comprehensive income	$ 18,779	$ 19,418	$ 35,618	$ 41,262

CONDENSED CONSOLIDATED STATEME5

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 38,781	$ 40,861
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	10,743	10,265
Amortization of debt issuance costs	725	725
Stock-based compensation	18,018	16,316
Deferred income taxes	4,384	2,499
Provision for excess and obsolete inventories	900	1,674
Restructuring and related charges (credits)	2,522	(1,463)
Cash payments for restructuring charges	(2,429)	(3,736)
Other operating activities	(1,141)	(849)
Changes in assets and liabilities:
Accounts receivable, net	1,246	(8,366)
Inventory, net	(5,844)	(1,102)
Current and other assets	(4,539)	(2,331)
Accounts payable	3,205	4,120
Accrued liabilities	(9,388)	10,444
Income taxes	(7,890)	(2,305)
Cash provided by operating activities	49,293	66,752
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds from sales of investments	30,895	125,504
Proceeds from maturities of investments	106,661	63,853
Purchase of investments	(133,949)	(192,349)
Capital expenditures	(6,752)	(14,191)
Cash used for investing activities	(3,145)	(17,183)
CASH FLOWS FROM FINANCING ACTIVITIES
Repurchase of common stock	(39,222)	(26,828)
Employees' tax withheld and paid for restricted stock and restricted stock units	(10,789)	(9,123)
Proceeds from issuances under stock-based compensation plans	11,950	5,752
Payment of cash dividends	(10,057)	(9,971)
Other financing activity	0	761
Cash used for financing activities	(48,118)	(39,409)
Effect of exchange rate changes on cash and cash equivalents	3,116	(971)
Net increase in cash and cash equivalents	1,146	9,189
Cash and cash equivalents at beginning of period	301,970	235,266
Cash and cash equivalents at end of period	303,116	244,455
SUPPLEMENTAL NON-CASH DISCLOSURES
Accounts payable for purchases of property, plant and equipment	$ 3,407	$ 2,718

BASIS OF PRESENTATION

BASIS OF PRESENTATION	6 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BASIS OF PRESENTATION	BASIS OF PRESENTATION In the opinion of management, the accompanying unaudited condensed consolidated financial statements ("financial statements") of Plantronics, Inc. ("Plantronics" or "the Company") have been prepared on a basis materially consistent with the Company's March 31, 2017 audited consolidated financial statements and include all adjustments, consisting of normal recurring adjustments, necessary to fairly state the information set forth herein. Certain information and footnote disclosures normally included in financial statements prepared pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC") applicable to interim financial information and in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") have been condensed or omitted pursuant to such rules and regulations. The financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company's Annual Report on Form 10-K for the fiscal year ended March 31, 2017 , which was filed with the SEC on May 10, 2017 . The results of operations for the interim period ended September 30, 2017 are not necessarily indicative of the results to be expected for the entire fiscal year or any future period. The financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated. The Company’s fiscal year ends on the Saturday closest to the last day of March. The Company’s current and prior fiscal years end on March 31, 2018 and April 1, 2017 , respectively, and both consist of 52 weeks. The Company’s results of operations for the three and six months ended September 30, 2017 and October 1, 2016 both contain 13 weeks. For purposes of presentation, the Company has indicated its accounting year as ending on March 31 and its interim quarterly periods as ending on the applicable calendar month end. Certain immaterial reclassifications to our previously reported financial information have been made to conform to the current period presentation. In addition, refer to Note 2, Recent Accounting Pronouncements , for details regarding reclassifications made in our condensed consolidated statements of cash flows pursuant to the adoption of new share-based payment accounting guidance in the first quarter of Fiscal Year 2018. Earnings per common share: The Company has a share-based compensation plan under which employees, non-employee directors, and consultants may be granted share-based payment awards, including shares of restricted stock on which non-forfeitable dividends are paid on unvested shares. As such, shares of restricted stock are considered participating securities under the two-class method of calculating earnings per share. Historically, the two-class method of calculating earnings per share did not have a material impact on the Company's earnings per share calculation under the treasury stock method. Beginning in the second quarter of Fiscal Year 2018, the Company applied the two-class method of calculating earnings per share because the ratio of participating securities to the weighted average number of common shares outstanding has increased as compared to the historical average, and this dilution will continue if the Company continues to repurchase its common stock at current levels. For further details refer to Note 14 , Computation of Earnings Per Common Share . Immaterial Out-of-Period Correction: During the first quarter of Fiscal Year 2018, the Company recognized an out-of-period correction to its Fiscal Year 2017 geographic mix of taxable income, which resulted in an overstatement of Fiscal Year 2017 income tax expense by $2.8 million . The Company's correction, recognized in the quarter ended June 30, 2017, resulted in a $2.8 million benefit to income tax expense. The Company assessed the materiality of this error and concluded it was not material to Fiscal Year 2017 and is not expected to be material to the full Fiscal Year 2018.

RECENT ACCOUNTING PRONOUNCEMENT

RECENT ACCOUNTING PRONOUNCEMENTS	6 Months Ended
	Sep. 30, 2017
Accounting Changes and Error Corrections [Abstract]
RECENT ACCOUNTING PRONOUNCEMENTS	RECENT ACCOUNTING PRONOUNCEMENTS Recently Issued Pronouncements In May 2014, the Financial Accounting Standards Board ("FASB") issued guidance regarding revenue from contracts with customers. While the standard supersedes existing revenue recognition guidance, it closely aligns with current U.S. GAAP. Under the new standard, revenue will be recognized at the time control of a good or service is transferred to a customer for the amount of consideration received or to be 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. In March 2016, the FASB issued additional guidance concerning "Principal versus Agent" considerations (reporting revenue gross versus net); in April 2016, the FASB issued additional guidance on identifying performance obligations and licensing; and in May 2016, the FASB issued additional guidance on collectability, non-cash consideration, presentation of sales tax, and transition. These updates are intended to improve the operability and understandability of the implementation guidance and have the same effective date and transition requirements as the greater "contracts with customers" standard. The Company will adopt the standard, as amended, in the first quarter of its fiscal year ending March 31, 2019, utilizing the modified retrospective method of adoption. The Company has completed its initial review of the impact of this guidance, and does not anticipate a material impact on its revenue recognition practices. The Company will continue to assess all potential impacts of the standard, and currently believes the most significantly impacted areas are the following: • Software Revenue: The Company currently defers revenue for the value of software where vendor specific objective evidence ("VSOE") of fair value has not been established for undelivered items. Under Topic 606, revenue for such licenses will be recognized at the transfer of control, rather than ratably, as the VSOE requirement no longer applies and the value of the remaining services are not material in the context of the contract. At June 30, 2017, deferred revenue under Topic 605 for these licenses was $1.9 million . The Company expects the remaining balance of such deferred revenue will be eliminated as a cumulative effect adjustment of implementing Topic 606 in the first quarter of its fiscal year ending March 31, 2019. • Marketing Development Funds: The Company frequently provides marketing development funds to its channel partners. Under topic 605, our marketing development funds are recognized as a reduction of revenue at the later of when the related revenue is recognized or when the program is offered to the channel partner. Applying the criteria of Topic 606, these marketing development programs qualify as variable consideration, and are assigned as a reduction of the transaction price of the contract. This results in a timing difference such that all or some of the funds related to a program may be recognized in different periods than under Topic 605, depending on the circumstances. Based on analysis of prior periods, we anticipate that this timing difference impacts revenue by immaterial amounts in a given period. The full impact of the adjustment is still being analyzed by the Company. • Revenue Reserves: The Company establishes reserves for Discounts and Rebates and Sales Returns at the end of each fiscal period. These reserves are estimated based on current relevant and historical data, but there can be some variability associated with unforeseen changes in customer claim and return patterns. Under Topic 606, in cases where there is uncertainty around the variable consideration amount, a constraint, or an adjustment to ensure that a significant revenue reversal will not occur, on that consideration must be considered. Based on analysis of prior periods, we anticipate that impact of introducing this constraint will not materially impact revenue. The full impact of the adjustment is still being analyzed by the Company. In addition, the standard also requires new, expanded disclosures regarding revenue recognition. The Company will continue to monitor additional changes, modifications, clarifications or interpretations being undertaken by the FASB, which may impact its current conclusions. In January 2016, the FASB issued guidance regarding the recognition and measurement of financial assets and liabilities. Changes to the current U.S. GAAP model primarily affect 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 consolidated financial statements and related disclosures. In February 2016, the FASB issued guidance regarding both operating and financing leases, requiring lessees to recognize on their balance sheets "right-of-use assets" and corresponding lease liabilities, measured on a discounted basis over the lease term. Virtually all leases will be subject to this treatment except leases that meet the definition of a "short-term lease". For expense recognition, the dual model requiring leases to be classified as either operating or finance leases has been retained from the prior standard. Operating leases will result in straight-line expense while finance leases will result in a front-loaded expense pattern. Classification will use criteria very similar to those applied in current lease accounting, but without explicit bright lines. Extensive additional quantitative and qualitative disclosures, including significant judgments made by management, will be required to provide greater insight into the extent of expense recognized and expected to be recognized. The new lease guidance will essentially eliminate off-balance sheet financing. The guidance is effective for the Company's fiscal year ending March 31, 2020. The new standard must be adopted using a modified retrospective transition that provides for certain practical expedients and requires the new guidance to be applied at the beginning of the earliest comparative period presented. The Company expects adoption of this guidance will materially increase the assets and liabilities recorded on its Consolidated Balance Sheets, but is still evaluating the impact on its consolidated financial statements and related disclosures. In June 2016, the FASB issued guidance regarding the measurement of credit losses on financial instruments, which changes the impairment model for most financial assets. The new model uses a forward-looking expected loss method, which will generally result in earlier recognition of allowances for losses. The guidance is effective for the Company's fiscal year ending March 31, 2021 with early adoption permitted beginning in the first quarter of Fiscal Year 2020. The Company is currently evaluating the impact the adoption of this standard will have on its consolidated financial statements and related disclosures. In January 2017, the FASB issued guidance that revises the definition of a business, providing a more robust framework for determining when a set of assets and activities is deemed a business. The guidance is effective for the Company's fiscal year ending March 31, 2019, including interim periods within that year, and is not expected to have a significant impact on the Company's consolidated financial statements or related disclosures. In January 2017, the FASB issued guidance that simplifies the process required to test goodwill for impairment. The guidance is effective for the Company's fiscal year ending March 31, 2021, and is not expected to have a significant impact on the Company's consolidated financial statements or related disclosures. In March 2017, the FASB issued guidance related to the amortization of premiums on purchased callable debt securities. This guidance shortens the amortization period for certain callable debt securities purchased at a premium by requiring that the premium be amortized to the earliest call date instead of the maturity date. This guidance is effective for the Company's fiscal year ending March 31, 2020, including interim periods within that year. The Company is currently evaluating the impact the adoption of this standard will have on its consolidated financial statements and related disclosures, but expects the impact to be immaterial. In May 2017, the FASB issued guidance that clarifies the scope of modification accounting with respect to changes to the terms or conditions of a share-based payment award. This guidance is effective for the Company's fiscal year ending March 31, 2019, including interim periods within that year. The Company is currently evaluating the impact the adoption of this standard will have on its consolidated financial statements and related disclosures, but expects the impact to be immaterial. In August 2017, the FASB issued guidance that eliminates the requirement to separately measure and report hedge ineffectiveness and that generally requires, for qualifying hedges, the entire change in the fair value of a hedging instrument to be presented in the same income statement line as the hedged item. The guidance also modifies the accounting for components excluded from the assessment of hedge effectiveness, eases documentation and assessment requirements, and modifies certain disclosure requirements. The new standard must be adopted using a modified retrospective transition with a cumulative effect adjustment recorded to opening retained earnings as of the initial adoption date. This guidance is effective for the Company's fiscal year ending March 31, 2020, including interim periods within that year. The Company is currently evaluating the impact the adoption of this standard will have on its consolidated financial statements and related disclosures, but expects the impact to be immaterial. Recently Adopted Pronouncement Beginning Fiscal Year 2018, the Company adopted the FASB's new guidance, Improvements to Employee Share-Based Payment Accounting , which changes among other things, how the tax effects of share-based awards are recognized. This new guidance requires excess tax benefits and tax deficiencies to be recognized in the provision for income taxes as discrete items in the period when the awards vest or are settled, whereas previously such income tax effects were recorded as part of additional paid-in capital. The provision for income taxes for the three and six months ended September 30, 2017, included excess tax benefits of $0.1 million and $2.0 million , respectively, that reduced the Company's effective tax rate by 0.3 and 4.8 percentage points, respectively. The recognized excess tax benefits resulted from share-based compensation awards that vested or settled in the first three months of 2017. This guidance also eliminates the requirement to reclassify cash flows related to excess tax benefits from operating activities to financing activities on the consolidated statements of cash flows. The Company adopted this provision retrospectively by reclassifying $0.9 million of excess tax benefits from financing activities to operating activities in the condensed consolidated statement of cash flows for the six months ended September 30, 2016. The Company also excluded the related tax benefits when applying the treasury stock method for computing diluted shares outstanding on a prospective basis as required by this guidance. In addition, the Company elected to continue its current practice of estimating expected forfeitures. The Company made no changes to its presentation of withholding taxes on the settlement of share-based payment awards, which were already presented as financing activities. The amount of excess tax benefits and deficiencies recognized in the provision for income taxes will fluctuate from period-to-period based on the price of the Company’s stock, the volume of share-based instruments settled or vested, and the value assigned to share-based instruments under U.S. GAAP. Refer to additional discussion in Note 13, Income Taxes .

CASH, CASH EQUIVALENTS, AND INV

CASH, CASH EQUIVALENTS, AND INVESTMENTS	6 Months Ended
	Sep. 30, 2017
CASH, CASH EQUIVALENTS AND INVESTMENTS [Abstract]
CASH, CASH EQUIVALENTS, AND INVESTMENTS	CASH, CASH EQUIVALENTS, AND INVESTMENTS The following tables summarize the Company’s cash and available-for-sale securities’ amortized 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, 2017 and March 31, 2017 (in thousands): September 30, 2017 Amortized Gross Gross Fair Cash & Cash Equivalents Short-term investments (due in 1 year or less) Long-term investments (due in 1 to 3 years) Cash $ 290,429 $ — $ — $ 290,429 $ 290,429 $ — $ — Level 1: Mutual Funds 13,507 675 (27 ) 14,155 — 14,155 — US Treasury Notes 32,958 — (66 ) 32,892 — 20,084 12,808 Subtotal 46,465 675 (93 ) 47,047 — 34,239 12,808 Level 2: Government Agency Securities 47,851 — (139 ) 47,712 — 26,870 20,842 Commercial Paper 52,099 — — 52,099 11,185 40,914 — Corporate Bonds 146,781 126 (95 ) 146,812 — 78,730 68,082 Certificates of Deposits ("CDs") 21,532 14 — 21,546 1,502 16,525 3,519 Subtotal 268,263 140 (234 ) 268,169 12,687 163,039 92,443 Total cash, cash equivalents $ 605,157 $ 815 $ (327 ) $ 605,645 $ 303,116 $ 197,278 $ 105,251 March 31, 2017 Amortized Gross Gross Fair Cash & Cash Equivalents Short-term investments (due in 1 year or less) Long-term investments (due in 1 to 3 years) Cash $ 295,877 $ — $ — $ 295,877 $ 295,877 $ — $ — Level 1: Mutual Funds 12,079 352 (32 ) 12,399 — 12,399 — US Treasury Notes 35,960 — (68 ) 35,892 — 17,560 18,332 Subtotal 48,039 352 (100 ) 48,291 — 29,959 18,332 Level 2: Government Agency Securities 54,415 20 (164 ) 54,271 — 15,309 38,962 Commercial Paper 47,152 — — 47,152 6,093 41,059 — Corporate Bonds 141,508 64 (224 ) 141,348 — 73,676 67,672 Certificates of Deposits ("CDs") 20,383 3 — 20,386 — 18,176 2,210 Subtotal 263,458 87 (388 ) 263,157 6,093 148,220 108,844 Total cash, cash equivalents $ 607,374 $ 439 $ (488 ) $ 607,325 $ 301,970 $ 178,179 $ 127,176 As of September 30, 2017 and March 31, 2017 , with the exception of assets related to the Company's deferred compensation plan, all of the Company's investments are classified as available-for-sale securities. The carrying value of available-for-sale securities included in cash equivalents approximates fair value because of the short maturity of those instruments. For more information regarding the Company's deferred compensation plan, refer to Note 4 , Deferred Compensation . The Company did not incur any material realized or unrealized gains or losses in the three and six months ended September 30, 2016 and 2017 . There were no transfers between fair value measurement levels during the three and six months ended September 30, 2016 and 2017 . All financial assets and liabilities are recognized or disclosed at fair value in the financial statements or the accompanying notes thereto. Fair value is estimated by applying the following hierarchy, which prioritizes the inputs used to measure fair value into three levels and bases the categorization within the hierarchy upon the lowest level of input that is available and significant to the fair value measurement: Level 1 The Company's Level 1 financial assets consist of Mutual Funds and US Treasury Notes. The fair value of Level 1 financial instruments is measured based on the quoted market price of identical securities. Level 2 The Company's Level 2 financial assets and liabilities consist of Government Agency Securities, Commercial Paper, Corporate Bonds, and Certificates of Deposits ("CDs") , derivative foreign currency contracts, and long-term debt. The fair value of Level 2 investment securities is determined based on other observable inputs, including multiple non-binding quotes from independent pricing services. Non-binding quotes are based on proprietary valuation models that are prepared by the independent pricing services and use algorithms based on inputs such as observable market data, quoted market prices for similar securities, issuer spreads, and internal assumptions of the broker. The Company corroborates the reasonableness of non-binding quotes received from the independent pricing services using a variety of techniques depending on the underlying instrument, including: (i) comparing them to actual experience gained from the purchases and maturities of investment securities, (ii) comparing them to internally developed cash flow models based on observable inputs, and (iii) monitoring changes in ratings of similar securities and the related impact on fair value. The fair value of Level 2 derivative foreign currency contracts is determined using pricing models that use observable market inputs. For more information regarding the Company's derivative assets and liabilities, refer to Note 12 , Foreign Currency Derivatives . The fair value of Level 2 long-term debt is determined based on inputs that were observable in the market, including the trading price of the notes when available. For more information regarding the Company's 5.50% Senior Notes, refer to Note 7 , Debt. Level 3 The Company's unsecured revolving credit facility falls under the Level 3 hierarchy. The fair value of the Company’s line of credit approximates its carrying value because the interest rate is variable and approximates rates currently available to the Company.

DEFERRED COMPENSATION

DEFERRED COMPENSATION	6 Months Ended
	Sep. 30, 2017
Compensation Related Costs [Abstract]
DEFERRED COMPENSATION	DEFERRED COMPENSATION As of September 30, 2017 , the Company held bank deposits of $0.8 million and investments in mutual funds totaling $14.2 million , all of which related to debt and equity securities that are held in rabbi trusts under non-qualified deferred compensation plans. The total related deferred compensation liability was $15.5 million at September 30, 2017 . As of March 31, 2017 , the Company held bank deposits of $0.8 million and investments in mutual funds totaling $12.4 million . The total related deferred compensation liability at March 31, 2017 was $13.7 million . The bank deposits are recorded on the condensed consolidated balance sheets under "cash and cash equivalents". The securities are classified as trading securities and are recorded on the condensed consolidated balance sheets under "short-term investments". The liability is recorded on the condensed consolidated balance sheets under "other long-term liabilities" and "accrued liabilities".

DETAILS OF CERTAIN BALANCE SHEE

DETAILS OF CERTAIN BALANCE SHEET ACCOUNTS	6 Months Ended
	Sep. 30, 2017
Balance Sheet Related Disclosures [Abstract]
DETAILS OF CERTAIN BALANCE SHEET ACCOUNTS	DETAILS OF CERTAIN BALANCE SHEET ACCOUNTS Accounts receivable, net: March 31, September 30, (in thousands) 2017 2017 Accounts receivable $ 184,068 $ 186,870 Provisions for returns (10,541 ) (9,865 ) Provisions for promotions, rebates, and other (31,747 ) (36,513 ) Provisions for doubtful accounts and sales allowances (603 ) (809 ) Accounts receivable, net $ 141,177 $ 139,683 Inventory, net: March 31, September 30, (in thousands) 2017 2017 Raw materials $ 20,260 $ 22,668 Work in process 215 237 Finished goods 34,981 38,094 Inventory, net $ 55,456 $ 60,999 Accrued Liabilities: March 31, September 30, (in thousands) 2017 2017 Employee compensation and benefits $ 36,415 $ 22,278 Accrued interest on 5.50% Senior Notes 10,407 10,312 Warranty obligation 6,863 6,739 VAT/Sales tax payable 5,433 5,852 Derivative liabilities 1,323 4,588 Accrued other 13,844 18,665 Accrued liabilities $ 74,285 $ 68,434 The Company's warranty obligation is included as a component of accrued liabilities on the condensed consolidated balance sheets. Changes in the warranty obligation during the six months ended September 30, 2016 and 2017 were as follows: Six Months Ended (in thousands) 2016 2017 Warranty obligation at beginning of period $ 8,537 $ 8,697 Warranty provision related to products shipped 4,649 4,635 Deductions for warranty claims processed (4,742 ) (5,080 ) Adjustments related to preexisting warranties 96 405 Warranty obligation at end of period (1) $ 8,540 $ 8,657 (1) Includes both short-term and long-term portion of warranty obligation; the prior table shows only the short-term portion included in accrued liabilities on our condensed consolidated balance sheet. The long-term portion is included in other long-term liabilities.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	6 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Unconditional Purchase Obligations The Company purchases materials and services from a variety of suppliers and manufacturers. During the normal course of business and to manage manufacturing operations and general and administrative activities, the Company may enter into firm, non-cancelable, and unconditional purchase obligations for which amounts are not recorded on the consolidated balance sheets. As of September 30, 2017 , the Company had outstanding off-balance sheet third-party manufacturing, component purchase, and other general and administrative commitments of $176.2 million . Other Guarantees and Obligations 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 indemnification to customers against claims related to undiscovered liabilities, additional product liability, or environmental obligations. The Company has also entered into indemnification agreements with its directors, officers and certain other personnel 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 or certain of its affiliated entities. The Company maintains director and officer liability insurance, which may cover certain liabilities arising from its obligation to indemnify its directors, officers and certain other personnel 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. Claims and Litigation On October 12, 2012, GN Netcom, Inc. ("GN") sued the Company 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 alleged four causes of action: monopolization, attempted monopolization, concerted action in restraint of trade, and tortious interference with business relations. GN claimed 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 asserted that the Company attracts SIDs through exclusive distributor agreements and alleged that the use of these agreements is illegal. On July 6, 2016, the Court in GN Netcom, Inc. v. Plantronics, Inc. ordered the following sanctions against the Company as they relate to certain discovery matters in the litigation: (1) monetary sanctions in the form of reasonable fees and costs incurred by GN in connection with the discovery disputes leading to the motion for sanctions; (2) punitive sanctions in the amount of $3 million ; (3) possible evidentiary sanctions; and (4) instructions to the jury that it may draw an adverse inference that emails destroyed by the Company would have been favorable to GN’s case and/or unfavorable to the Company's defense. As a result, during the three months ended June 30, 2016, the Company accrued $3 million for the punitive sanctions and an additional $2 million , representing the Company’s best estimate of reasonable fees and costs incurred by GN in connection with the disputes leading to the motion for sanctions, for a total of $5 million . The Company paid the $3 million in punitive damages to GN on or about September 1, 2016 and paid the remaining balance, which was reduced to $1.9 million , on December 7, 2016. The parties conducted fact and expert discovery through December 2016. In February 2017, the court granted the Company’s request to file a summary judgment motion, which the Company subsequently filed in April 2017. The court denied that motion in August 2017. GN also filed a motion for sanctions, which the court denied in July 2017. Both sides also filed Daubert motions to exclude certain expert testimony; those motions were denied in August. Trial of this matter commenced on October 11, 2017, subsequent to the Company's second quarter of Fiscal Year 2018. On October 18, 2017, the jury reached a verdict in favor of the Company on all counts, with no damages awarded to GN. In a letter dated May 1, 2017, the Company received a Notice of Proposed Debarment from the General Services Administration ("GSA"). That matter was dismissed by the GSA upon a finding of no cause in August 2017. In addition to the specific matter 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.

DEBT

DEBT	6 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
DEBT	DEBT 5.50% Senior Notes In May 2015, the Company 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, commencing on November 15, 2015. The Company received net proceeds of $488.4 million from the 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. A portion of the proceeds was used to repay all then-outstanding amounts under our revolving line of credit agreement with Wells Fargo Bank and the remaining proceeds were used primarily for share repurchases. 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: March 31, 2017 September 30, 2017 (in thousands) Fair Value Carrying Value Fair Value Carrying Value 5.50% Senior Notes $ 505,150 $ 491,059 $ 520,205 $ 491,784 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: Redemption Period Requiring Payment of: Redemption Up To 35% Using Cash Proceeds From An Equity Offering (3) : Make-Whole (1) Premium (2) Date Specified Price 5.50% Senior Notes Prior to May 15, 2018 On or after May 15, 2018 Prior to May 15, 2018 105.500% (1) If the Company redeems the notes prior to the applicable date, the redemption price is principal plus a make-whole premium equal to the present value of the remaining scheduled interest payments as described in the applicable indenture, together with accrued and unpaid interest. (2) If the Company redeems the notes on or after the applicable date, the price is principal plus a premium which declines over time as specified in the applicable indenture, together with accrued and unpaid interest. (3) If the Company redeems the notes prior to the applicable date with net cash proceeds of one or more equity offerings, the price is equal to the amount specified above, together with accrued and unpaid interest, subject to a maximum redemption of 35% of the aggregate principal amount of the respective note being redeemed. 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 the Company's ability to create certain liens and enter into sale and leaseback transactions; create, assume, incur, or guarantee additional indebtedness of its 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 the Company and its subsidiaries to another person. As of September 30, 2017 , the Company was in compliance with all covenants. Revolving Credit Agreement On May 9, 2011 , the Company entered into a credit agreement with Wells Fargo Bank, National Association ("the Bank"), which was most recently amended on April 28, 2017 (as amended, the "Amended Credit Agreement") to extend the term of the Credit Agreement by one year to May 9, 2020 , and to amend certain of the covenants, which are defined below. The Amended Credit Agreement provides for a $100.0 million unsecured revolving credit facility. 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 of April, July, October and January. Principal, together with all accrued and unpaid interest, on the revolving loans is due and payable on May 9, 2020 . 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 of April, July, October and January. 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 March 31, 2017 and September 30, 2017 , the Company had no outstanding borrowings under the line of credit. The Amended 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 Amended Credit Agreement also requires the Company to comply with certain financial covenants, including (i) a maximum ratio of funded debt to EBITDA of 3.25:1 (previously 3:1) 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 Amended Credit Agreement at the end of each fiscal quarter of at least $300.0 million . The Amended 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 Amended Credit Agreement. As of March 31, 2017 and September 30, 2017 , the Company was in compliance with all covenants.

RESTRUCTURING AND OTHER RELATED

RESTRUCTURING AND OTHER RELATED CHARGES (CREDITS)	6 Months Ended
	Sep. 30, 2017
Restructuring and Related Activities [Abstract]
RESTRUCTURING AND OTHER RELATED CHARGES (CREDITS)	RESTRUCTURING AND OTHER RELATED CHARGES (CREDITS) During the first six months of Fiscal Year 2018 and as part of its ongoing effort to reduce costs, improve profitability, and focus on its key strategic initiatives, the Company executed an asset sale agreement to dispose of substantially all assets of its Clarity division, primarily inventories and tooling fixed assets, for an immaterial sales price. The buyer in this arrangement was a former employee of the Company, who acted as Clarity's President but who was not an executive officer or director of the Company. As part of the buyer's separation from Plantronics, the Company accelerated vesting on his outstanding restricted stock, resulting in an immaterial stock-compensation modification charge. In connection with the sale, the Company is leasing the facility it owns in Chattanooga, Tennessee, to the buyer for a period of twelve months. The Company also entered into a transition services agreement with the buyer to provide customer support services on a cost-recovery basis, which are not expected to be material, for a period of one year. The Company also recorded immaterial impairment charges on assets previously used in Clarity operations that have no further value to the Company. In addition to the sale of the Clarity division and the related restructuring actions, the Company reduced headcount in certain divisions and terminated a lease in the Netherlands before the end of its contractual term, resulting in a charge equal to the present value of the remaining future minimum lease payments. In connection with this exit, the Company wrote off certain fixed assets that will no longer be used. Finally, the Company reorganized its Brazilian operations and as a result, wrote off an unrecoverable indirect tax asset. As of September 30, 2017 , the remaining obligation related to severance amounts due is immaterial and will be settled within 12 months. During the quarter ended September 30, 2017, we recorded an immaterial adjustment to restructuring and other related charges (credits) resulting from a change in estimate from amounts previously recorded. The associated charges for the six months ended September 30, 2017 are recorded in restructuring and other related charges (credits), cost of revenues, and selling, general, and administrative expense in the condensed consolidated statements of operations, as follows: Six months ended September 30, 2017 (in millions) Total Charges Restructuring and Other Related Charges (Credits) Cost of Revenues Selling, General, and Administrative Severance benefits from reduction-in-force $ 1.4 $ 1.4 $ — $ — Lease exit charge and asset impairments in Netherlands 0.7 0.7 — — Write-off of unrecoverable indirect tax asset in Brazil 0.7 — 0.7 — Asset impairments related to previous Clarity operations 0.4 0.4 — — Loss on Clarity asset sale 0.9 — 0.9 — Accelerated vesting of restricted stock 0.2 — — 0.2 Totals $ 4.3 $ 2.5 $ 1.6 $ 0.2

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	6 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION 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: Three Months Ended Six Months Ended (in thousands) 2016 2017 2016 2017 Cost of revenues $ 778 $ 890 $ 1,620 $ 1,792 Research, development, and engineering 2,408 2,008 4,892 4,109 Selling, general, and administrative 4,717 5,864 9,804 12,117 Stock-based compensation included in operating expenses 7,125 7,872 14,696 16,226 Total stock-based compensation 7,903 8,762 16,316 18,018 Income tax benefit (2,877 ) (2,840 ) (5,649 ) (7,689 ) Total stock-based compensation, net of tax $ 5,026 $ 5,922 $ 10,667 $ 10,329

COMMON STOCK REPURCHASES

COMMON STOCK REPURCHASES	6 Months Ended
	Sep. 30, 2017
Equity [Abstract]
COMMON STOCK REPURCHASES	COMMON STOCK REPURCHASES From time to time, the Company's Board of Directors (the "Board") has authorized programs under which the Company may repurchase shares of its common stock, depending on market conditions, in the open market or through privately negotiated transactions. Repurchased shares are held as treasury stock until they are retired or re-issued. Repurchases by the Company pursuant to Board-authorized programs during the six months ended September 30, 2016 and 2017 are discussed below. As of September 30, 2017 , there remained 1,028,586 shares authorized for repurchase under the repurchase programs approved by the Board on July 29, 2016 and July 27, 2017 . There were no remaining shares authorized under previously approved programs. In the six months ended September 30, 2016 and 2017 , the Company repurchased 613,021 shares and 841,249 shares, respectively, of its common stock in the open market for a total cost of $26.8 million and $39.2 million , respectively, and at an average price per share of $43.76 and $46.62 , respectively. In addition, the Company withheld shares valued at $9.1 million and $10.8 million in the six months ended September 30, 2016 and 2017 , respectively, in satisfaction of employee tax withholding obligations upon the vesting of restricted stock granted under the Company's stock plans. The amounts withheld were equivalent to the employees' minimum statutory tax withholding requirements and are reflected as a financing activity within the Company's condensed consolidated statements of cash flows. These share withholdings have the same effect as share repurchases by the Company as they reduce the number of shares that would have otherwise been issued in connection with the vesting of shares subject to the restricted stock grants.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME	6 Months Ended
	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
ACCUMULATED OTHER COMPREHENSIVE INCOME	ACCUMULATED OTHER COMPREHENSIVE INCOME The components of accumulated other comprehensive income ("AOCI"), net of immaterial tax effects, are as follows: (in thousands) March 31, 2017 September 30, 2017 Accumulated unrealized gain (loss) on cash flow hedges (1) $ 529 $ (3,039 ) Accumulated foreign currency translation adjustments 4,428 4,685 Accumulated unrealized gain (loss) on investments (263 ) (115 ) Accumulated other comprehensive income $ 4,694 $ 1,531 (1) Refer to Note 12 , Foreign Currency Derivatives, which discloses the nature of the Company's derivative assets and liabilities as of March 31, 2017 and September 30, 2017 .

FOREIGN CURRENCY DERIVATIVES

FOREIGN CURRENCY DERIVATIVES	6 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
FOREIGN CURRENCY DERIVATIVES	FOREIGN CURRENCY DERIVATIVES The Company's foreign currency derivatives consist primarily of foreign currency forward exchange contracts, option contracts, and cross-currency swaps. The Company does not purchase derivative financial instruments for speculative trading purposes. The derivatives expose the Company to credit risk to the extent the counterparties may be unable to meet the terms of the derivative instrument. The Company's maximum exposure to loss that it would incur due to credit risk if parties to derivative contracts failed completely to perform according to the terms of the contracts was equal to the carrying value of the Company's derivative assets as of September 30, 2017 . The Company seeks to mitigate such risk by limiting its counterparties to large financial institutions. In addition, the Company monitors the potential risk of loss with any one counterparty resulting from this type of credit risk on an ongoing basis. The Company enters into master netting arrangements with counterparties when possible to mitigate credit risk in derivative transactions. A master netting arrangement may allow each counterparty to net settle amounts owed between the Company and the counterparty as a result of multiple, separate derivative transactions. As of September 30, 2017 , the Company had International Swaps and Derivatives Association (ISDA) agreements with four applicable banks and financial institutions which contained netting provisions. Plantronics has elected to present the fair value of derivative assets and liabilities on the Company's condensed consolidated balance sheet on a gross basis even when derivative transactions are subject to master netting arrangements and may otherwise qualify for net presentation. For each counterparty, if netted, the Company would offset the asset and liability balances of all derivatives at the end of the reporting period. Derivatives not subject to master netting agreements are not eligible for net presentation. As of March 31, 2017 and September 30, 2017 , no cash collateral had been received or pledged related to these derivative instruments. The gross fair value of the Company's outstanding derivative contracts at the end of each period was as follows: (in thousands) March 31, 2017 September 30, 2017 Derivative Assets (1) Non-designated hedges $ 86 $ 310 Cash flow hedges 2,034 505 Total Derivative Assets $ 2,120 $ 815 Derivative Liabilities (2) Non-designated hedges $ 286 $ 339 Cash flow hedges 1,109 4,346 Total Derivative Liabilities $ 1,395 $ 4,685 (1) Short-term derivative assets are recorded in "other current assets" and long-term derivative assets are recorded in "deferred tax and other assets". As of September 30, 2017 the portion of derivative assets classified as long-term was immaterial. (2) Short-term derivative liabilities are recorded in "accrued liabilities" and long-term derivative liabilities are recorded in "other long-term liabilities". As of September 30, 2017 the portion of derivative liabilities classified as long-term was immaterial. Non-Designated Hedges As of September 30, 2017 , the Company had foreign currency forward contracts denominated in Euros ("EUR"), British Pound Sterling ("GBP"), Australian Dollars ("AUD"), and Canadian Dollars ("CAD"). The Company does not elect to obtain hedge accounting for these forward contracts. These forward contracts hedge against a portion of the Company’s foreign currency-denominated cash balances, receivables, and payables. The following table summarizes the notional value of the Company’s outstanding foreign exchange currency contracts and approximate U.S. Dollar ("USD") equivalent at September 30, 2017 : (in thousands) Local Currency USD Equivalent Position Maturity EUR € 33,900 $ 28,650 Sell EUR 1 month GBP £ 5,000 $ 6,710 Sell GBP 1 month AUD A$ 13,200 $ 10,352 Sell AUD 1 month CAD C$ 2,700 $ 2,161 Sell CAD 1 month Effect of Non-Designated Derivative Contracts on the Condensed Consolidated Statements of Operations The effect of non-designated derivative contracts recognized in other non-operating income and (expense), net in the condensed consolidated statements of operations was as follows: Three Months Ended Six Months Ended (in thousands) 2016 2017 2016 2017 Gain (loss) on foreign exchange contracts $ (193 ) $ 2,102 $ 1,750 $ 5,236 Cash Flow Hedges Costless Collars 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. The notional value of the Company's outstanding EUR and GBP option and forward contracts at the end of each period was as follows: March 31, 2017 September 30, 2017 (in millions) EUR GBP EUR GBP Option contracts €73.5 £23.9 €81.7 £23.9 Forward contracts €11.2 £3.3 €13.4 £3.6 The Company will reclassify all amounts accumulated in other comprehensive income into earnings within the next twelve months. Cross-currency Swaps The Company hedges a portion of the forecasted Mexican Peso (“MXN”) denominated expenditures with a cross-currency swap. As of March 31, 2017 and September 30, 2017 , the Company had foreign currency swap contracts of approximately MXN 287.2 million and MXN 134.2 million , respectively. The following table summarizes the notional value of the Company’s outstanding MXN cross-currency swaps and approximate USD Equivalent at September 30, 2017 : (in thousands) Local Currency USD Equivalent Position Maturity MXN $ 134,150 $ 6,978 Buy MXN Monthly over 9 months Effect of Designated Derivative Contracts on AOCI and Condensed Consolidated Statements of Operations The following table presents the pre-tax effects of derivative instruments designated as cash flow hedges on accumulated other comprehensive income and the condensed consolidated statements of operations for the three and six months ended September 30, 2016 and 2017 : Three Months Ended Six Months Ended (in thousands) 2016 2017 2016 2017 Gain (loss) included in AOCI as of beginning of period $ 415 $ (1,744 ) $ (1,106 ) $ 541 Amount of gain (loss) recognized in other comprehensive income (“OCI”) (effective portion) (650 ) (2,302 ) 304 (4,647 ) Amount of gain (loss) reclassified from OCI into net revenues (effective portion) 825 1,131 985 1,149 Amount of gain (loss) reclassified from OCI into cost of revenues (effective portion) (589 ) (174 ) (1,316 ) (132 ) Total amount of gain (loss) reclassified from AOCI to income (loss) (effective portion) 236 957 (331 ) 1,017 Gain (loss) included in AOCI as of end of period $ (471 ) $ (3,089 ) $ (471 ) $ (3,089 ) During the three and six months ended September 30, 2016 and 2017 the Company recognized an immaterial gain and immaterial loss on the ineffective portion of its cash flow hedges, respectively, which is reported in other non-operating income and (expense), net in the condensed consolidated statements of operations.

INCOME TAXES

INCOME TAXES	6 Months Ended
	Sep. 30, 2017
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The Company and its subsidiaries are subject to taxation in the U.S. and in various foreign and state jurisdictions. The effective tax rates for the three months ended September 30, 2016 and 2017 were 21.4% and 19.3% , respectively. The effective tax rates for the six months ended September 30, 2016 and 2017 were 22.0% and 7.2% , respectively. The decrease in the effective tax rates for the three and six months ended September 30, 2017 is due primarily to a shift in geographic mix of taxable income from higher tax jurisdictions to lower tax jurisdictions. The effective tax rate for the six months ended September 30, 2017 further decreased due to the adoption of new guidance related to stock-based compensation. The Company recorded a correction to the geographic mix of income during the three months ended June 30, 2017 related to Fiscal Year 2017 which reduced income in a high tax jurisdiction and increased income in a low tax jurisdiction. This correction resulted in a reduction to the Company’s effective tax rate by 6.6 percentage points for the six months ended September 30, 2017 as compared to the prior year period. It had no impact on the three months ended September 30, 2017. For additional details regarding this correction refer to Note 1, Basis of Presentation . The Company adopted new stock-based compensation accounting guidance effective the beginning of Fiscal Year 2018. Excess tax benefits associated with employee equity plans were previously recorded in additional paid-in capital and the adoption of this guidance resulted in a reduction to the Company's effective tax rate by 0.3 and 4.8 percentage points for the three and six months ended September 30, 2017, respectively. The amount of excess tax benefits or deficiencies will fluctuate from period-to-period based on the price of the Company’s stock, the volume of share-based instruments settled or vested, and the value assigned to employee equity awards under U.S. GAAP. Included in long-term income taxes payable in the condensed consolidated balance sheets as of March 31, 2017 and September 30, 2017 were unrecognized tax benefits of $12.9 million and $13.4 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 $1.7 million and $1.6 million as of March 31, 2017 and September 30, 2017 , respectively. No penalties have been accrued. The Company and its subsidiaries are subject to taxation in the U.S. federal and various foreign and state jurisdictions. The Company’s Fiscal Year 2016 federal income tax return is currently under examination by the Internal Revenue Service. Foreign income tax matters for material tax jurisdictions have been concluded for tax years prior to Fiscal Year 2012. 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.

COMPUTATION OF EARNINGS PER COM

COMPUTATION OF EARNINGS PER COMMON SHARE	6 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
COMPUTATION OF EARNINGS PER COMMON SHARE	COMPUTATION OF EARNINGS PER COMMON SHARE Basic and diluted earnings per share are computed using the two-class method. The two-class method is an earnings allocation formula that determines net income per share for each class of common stock and participating security according to dividends declared and participation rights in undistributed earnings. Per share amounts are computed by dividing net income attributable to common shareholders by the weighted average shares outstanding during each period. The Company has a share-based compensation plan under which employees, non-employee directors, and consultants may be granted share-based awards, including shares of restricted stock on which non-forfeitable dividends are paid on unvested shares. As such, shares of restricted stock are considered participating securities under the two-class method of calculating earnings per share. Prior to the second quarter of Fiscal Year 2018, the impact of the two-class method was not considered material and therefore, earnings per share was reported as calculated under the treasury stock method. Had the Company reported earnings per share under the two-class method, basic and diluted earnings per share would have been $0.62 and $0.61, respectively, for the three months ended September 30, 2016 instead of the reported amounts of $0.63 and $0.63, respectively. For the six months ended September 30, 2016, basic and diluted earnings per share would have been $1.23 and $1.21, respectively, instead of the the reported amounts of $1.27 and $1.24, respectively. The following table sets forth the computation of basic and diluted earnings per common share for the three and six months ended September 30, 2016 and 2017: Three Months Ended Six Months Ended (in thousands, except per share data) 2016 (1) 2017 2016 (1) 2017 Basic earnings per common share: Numerator: Net income $ 20,474 $ 19,953 $ 40,861 $ 38,781 Income allocated to participating securities, basic n/a (597 ) n/a (1,169 ) Net income attributable to common shareholders, basic $ 20,474 $ 19,356 $ 40,861 $ 37,612 Denominator: Weighted average common shares, basic 32,281 32,570 32,269 32,538 Basic earnings per common share $ 0.63 $ 0.59 $ 1.27 $ 1.16 Diluted earnings per common share: Numerator: Net income attributable to common shareholders, basic $ 20,474 $ 19,356 $ 40,861 $ 37,612 Net effect of reallocating undistributed earnings of unvested shareholders n/a 3 n/a 15 Net income attributable to common shareholders, diluted $ 20,474 $ 19,359 $ 40,861 $ 37,627 Denominator: Weighted average common shares-basic 32,281 32,570 32,269 32,538 Dilutive effect of employee equity incentive plans 445 239 596 573 Weighted average common shares, diluted 32,726 32,809 32,865 33,111 Diluted earnings per common share $ 0.63 $ 0.59 $ 1.24 $ 1.14 Potentially dilutive securities excluded from diluted earnings per common share because their effect is anti-dilutive 543 1,389 634 959 (1) As previously disclosed in forms 10-Q and 10-K for Fiscal Year 2017, the two-class method of calculating earnings per share did not have a material impact on the Company's earnings per share calculation for the three and six months ended September 30. 2016; as such, these periods have not been adjusted to reflect the two-class method of calculating earnings per share in the above table.

REVENUE AND MAJOR CUSTOMERS

REVENUE AND MAJOR CUSTOMERS	6 Months Ended
	Sep. 30, 2017
REVENUE AND MAJOR CUSTOMERS [Abstract]
REVENUE AND MAJOR CUSTOMERS	REVENUE AND MAJOR CUSTOMERS The Company designs, manufactures, markets, and sells headsets for business and consumer applications. With respect to headsets, the Company makes products for use in offices and contact centers and, with mobile devices, cordless phones, computers, and gaming consoles. The following table presents net revenues by product group for the three and six months ended September 30, 2016 and 2017 : Three Months Ended Six Months Ended (in thousands) 2016 2017 2016 2017 Net revenues from unaffiliated customers: Enterprise $ 154,542 $ 162,907 $ 310,439 $ 317,512 Consumer 61,641 47,393 128,850 96,714 Total net revenues $ 216,183 $ 210,300 $ 439,289 $ 414,226 For reporting purposes, revenue is attributed to each geographic region based on the location of the customer. Other than the U.S., no country accounted for 10% or more of the Company's net revenues for the three and six months ended September 30, 2016 and 2017 . The following table presents net revenues by geography: Three Months Ended Six Months Ended (in thousands) 2016 2017 2016 2017 Net revenues from unaffiliated customers: U.S. $ 119,062 $ 111,095 $ 247,300 $ 219,905 Europe and Africa 51,422 56,325 105,489 111,141 Asia Pacific 28,588 24,227 54,815 48,111 Americas, excluding U.S. 17,111 18,653 31,685 35,069 Total international net revenues 97,121 99,205 191,989 194,321 Total net revenues $ 216,183 $ 210,300 $ 439,289 $ 414,226 One customer, Ingram Micro Group, accounted for 10.7% and 10.4% of net revenues for the three and six months ended September 30, 2016 . One customer, Ingram Micro Group, accounted for 12.4% and 12.2% of net revenues for the three and six months ended September 30, 2017 , respectively. One customer, Ingram Micro Group, accounted for 17.6% of total net accounts receivable at March 31, 2017 . Two customers, Ingram Micro Group and D&H Distributors, accounted for 15.4% and 11.5% , respectively, of total net accounts receivable at September 30, 2017 .

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	6 Months Ended
	Sep. 30, 2017
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS On October 31, 2017 , the Company announced that its Audit Committee had declared and approved the payment of a dividend of $0.15 per share on December 8, 2017 to holders of record on November 20, 2017 . On October 18, 2017, the Company received a favorable verdict in the antitrust action brought by GN Netcom, Inc. in the U.S. District Court for the District of Delaware. For additional details, refer to Note 6, Commitments and Contingencies .

BASIS OF PRESENTATION (Policies

BASIS OF PRESENTATION (Policies)	6 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of presentation	In the opinion of management, the accompanying unaudited condensed consolidated financial statements ("financial statements") of Plantronics, Inc. ("Plantronics" or "the Company") have been prepared on a basis materially consistent with the Company's March 31, 2017 audited consolidated financial statements and include all adjustments, consisting of normal recurring adjustments, necessary to fairly state the information set forth herein. Certain information and footnote disclosures normally included in financial statements prepared pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC") applicable to interim financial information and in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") have been condensed or omitted pursuant to such rules and regulations. The financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company's Annual Report on Form 10-K for the fiscal year ended March 31, 2017 , which was filed with the SEC on May 10, 2017 . The results of operations for the interim period ended September 30, 2017 are not necessarily indicative of the results to be expected for the entire fiscal year or any future period. The financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated.
Fiscal period	The Company’s fiscal year ends on the Saturday closest to the last day of March. The Company’s current and prior fiscal years end on March 31, 2018 and April 1, 2017 , respectively, and both consist of 52 weeks. The Company’s results of operations for the three and six months ended September 30, 2017 and October 1, 2016 both contain 13 weeks. For purposes of presentation, the Company has indicated its accounting year as ending on March 31 and its interim quarterly periods as ending on the applicable calendar month end.
Earnings per common share	Earnings per common share: The Company has a share-based compensation plan under which employees, non-employee directors, and consultants may be granted share-based payment awards, including shares of restricted stock on which non-forfeitable dividends are paid on unvested shares. As such, shares of restricted stock are considered participating securities under the two-class method of calculating earnings per share. Historically, the two-class method of calculating earnings per share did not have a material impact on the Company's earnings per share calculation under the treasury stock method. Beginning in the second quarter of Fiscal Year 2018, the Company applied the two-class method of calculating earnings per share because the ratio of participating securities to the weighted average number of common shares outstanding has increased as compared to the historical average, and this dilution will continue if the Company continues to repurchase its common stock at current levels.

CASH, CASH EQUIVALENTS, AND I23

CASH, CASH EQUIVALENTS, AND INVESTMENTS (Tables)	6 Months Ended
	Sep. 30, 2017
CASH, CASH EQUIVALENTS AND INVESTMENTS [Abstract]
Cash, Cash Equivalents, and Investments	The following tables summarize the Company’s cash and available-for-sale securities’ amortized 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, 2017 and March 31, 2017 (in thousands): September 30, 2017 Amortized Gross Gross Fair Cash & Cash Equivalents Short-term investments (due in 1 year or less) Long-term investments (due in 1 to 3 years) Cash $ 290,429 $ — $ — $ 290,429 $ 290,429 $ — $ — Level 1: Mutual Funds 13,507 675 (27 ) 14,155 — 14,155 — US Treasury Notes 32,958 — (66 ) 32,892 — 20,084 12,808 Subtotal 46,465 675 (93 ) 47,047 — 34,239 12,808 Level 2: Government Agency Securities 47,851 — (139 ) 47,712 — 26,870 20,842 Commercial Paper 52,099 — — 52,099 11,185 40,914 — Corporate Bonds 146,781 126 (95 ) 146,812 — 78,730 68,082 Certificates of Deposits ("CDs") 21,532 14 — 21,546 1,502 16,525 3,519 Subtotal 268,263 140 (234 ) 268,169 12,687 163,039 92,443 Total cash, cash equivalents $ 605,157 $ 815 $ (327 ) $ 605,645 $ 303,116 $ 197,278 $ 105,251 March 31, 2017 Amortized Gross Gross Fair Cash & Cash Equivalents Short-term investments (due in 1 year or less) Long-term investments (due in 1 to 3 years) Cash $ 295,877 $ — $ — $ 295,877 $ 295,877 $ — $ — Level 1: Mutual Funds 12,079 352 (32 ) 12,399 — 12,399 — US Treasury Notes 35,960 — (68 ) 35,892 — 17,560 18,332 Subtotal 48,039 352 (100 ) 48,291 — 29,959 18,332 Level 2: Government Agency Securities 54,415 20 (164 ) 54,271 — 15,309 38,962 Commercial Paper 47,152 — — 47,152 6,093 41,059 — Corporate Bonds 141,508 64 (224 ) 141,348 — 73,676 67,672 Certificates of Deposits ("CDs") 20,383 3 — 20,386 — 18,176 2,210 Subtotal 263,458 87 (388 ) 263,157 6,093 148,220 108,844 Total cash, cash equivalents $ 607,374 $ 439 $ (488 ) $ 607,325 $ 301,970 $ 178,179 $ 127,176

DETAILS OF CERTAIN BALANCE SH24

DETAILS OF CERTAIN BALANCE SHEET ACCOUNTS (Tables)	6 Months Ended
	Sep. 30, 2017
Balance Sheet Related Disclosures [Abstract]
Accounts receivable, net	Accounts receivable, net: March 31, September 30, (in thousands) 2017 2017 Accounts receivable $ 184,068 $ 186,870 Provisions for returns (10,541 ) (9,865 ) Provisions for promotions, rebates, and other (31,747 ) (36,513 ) Provisions for doubtful accounts and sales allowances (603 ) (809 ) Accounts receivable, net $ 141,177 $ 139,683
Inventory, net	Inventory, net: March 31, September 30, (in thousands) 2017 2017 Raw materials $ 20,260 $ 22,668 Work in process 215 237 Finished goods 34,981 38,094 Inventory, net $ 55,456 $ 60,999
Accrued liabilities	Accrued Liabilities: March 31, September 30, (in thousands) 2017 2017 Employee compensation and benefits $ 36,415 $ 22,278 Accrued interest on 5.50% Senior Notes 10,407 10,312 Warranty obligation 6,863 6,739 VAT/Sales tax payable 5,433 5,852 Derivative liabilities 1,323 4,588 Accrued other 13,844 18,665 Accrued liabilities $ 74,285 $ 68,434
Changes in the warranty obligation	Changes in the warranty obligation during the six months ended September 30, 2016 and 2017 were as follows: Six Months Ended (in thousands) 2016 2017 Warranty obligation at beginning of period $ 8,537 $ 8,697 Warranty provision related to products shipped 4,649 4,635 Deductions for warranty claims processed (4,742 ) (5,080 ) Adjustments related to preexisting warranties 96 405 Warranty obligation at end of period (1) $ 8,540 $ 8,657 (1) Includes both short-term and long-term portion of warranty obligation; the prior table shows only the short-term portion included in accrued liabilities on our condensed consolidated balance sheet. The long-term portion is included in other long-term liabilities.

DEBT (Tables)

DEBT (Tables)	6 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Summary of Debt at Fair Value	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: March 31, 2017 September 30, 2017 (in thousands) Fair Value Carrying Value Fair Value Carrying Value 5.50% Senior Notes $ 505,150 $ 491,059 $ 520,205 $ 491,784
Summary of Debt Redemption	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: Redemption Period Requiring Payment of: Redemption Up To 35% Using Cash Proceeds From An Equity Offering (3) : Make-Whole (1) Premium (2) Date Specified Price 5.50% Senior Notes Prior to May 15, 2018 On or after May 15, 2018 Prior to May 15, 2018 105.500% (1) If the Company redeems the notes prior to the applicable date, the redemption price is principal plus a make-whole premium equal to the present value of the remaining scheduled interest payments as described in the applicable indenture, together with accrued and unpaid interest. (2) If the Company redeems the notes on or after the applicable date, the price is principal plus a premium which declines over time as specified in the applicable indenture, together with accrued and unpaid interest. (3) If the Company redeems the notes prior to the applicable date with net cash proceeds of one or more equity offerings, the price is equal to the amount specified above, together with accrued and unpaid interest, subject to a maximum redemption of 35% of the aggregate principal amount of the respective note being redeemed.

RESTRUCTURING AND OTHER RELAT26

RESTRUCTURING AND OTHER RELATED CHARGES (CREDITS) (Tables)	6 Months Ended
	Sep. 30, 2017
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs	The associated charges for the six months ended September 30, 2017 are recorded in restructuring and other related charges (credits), cost of revenues, and selling, general, and administrative expense in the condensed consolidated statements of operations, as follows: Six months ended September 30, 2017 (in millions) Total Charges Restructuring and Other Related Charges (Credits) Cost of Revenues Selling, General, and Administrative Severance benefits from reduction-in-force $ 1.4 $ 1.4 $ — $ — Lease exit charge and asset impairments in Netherlands 0.7 0.7 — — Write-off of unrecoverable indirect tax asset in Brazil 0.7 — 0.7 — Asset impairments related to previous Clarity operations 0.4 0.4 — — Loss on Clarity asset sale 0.9 — 0.9 — Accelerated vesting of restricted stock 0.2 — — 0.2 Totals $ 4.3 $ 2.5 $ 1.6 $ 0.2

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	6 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation Expense Included in Statements of Operations	The following table summarizes the amount of stock-based compensation included in the condensed consolidated statements of operations: Three Months Ended Six Months Ended (in thousands) 2016 2017 2016 2017 Cost of revenues $ 778 $ 890 $ 1,620 $ 1,792 Research, development, and engineering 2,408 2,008 4,892 4,109 Selling, general, and administrative 4,717 5,864 9,804 12,117 Stock-based compensation included in operating expenses 7,125 7,872 14,696 16,226 Total stock-based compensation 7,903 8,762 16,316 18,018 Income tax benefit (2,877 ) (2,840 ) (5,649 ) (7,689 ) Total stock-based compensation, net of tax $ 5,026 $ 5,922 $ 10,667 $ 10,329

ACCUMULATED OTHER COMPREHENSI28

ACCUMULATED OTHER COMPREHENSIVE INCOME (Tables)	6 Months Ended
	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Accumulated Other Comprehensive Income	The components of accumulated other comprehensive income ("AOCI"), net of immaterial tax effects, are as follows: (in thousands) March 31, 2017 September 30, 2017 Accumulated unrealized gain (loss) on cash flow hedges (1) $ 529 $ (3,039 ) Accumulated foreign currency translation adjustments 4,428 4,685 Accumulated unrealized gain (loss) on investments (263 ) (115 ) Accumulated other comprehensive income $ 4,694 $ 1,531 (1) Refer to Note 12 , Foreign Currency Derivatives, which discloses the nature of the Company's derivative assets and liabilities as of March 31, 2017 and September 30, 2017 .

FOREIGN CURRENCY DERIVATIVES (T

FOREIGN CURRENCY DERIVATIVES (Tables)	6 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of Outstanding Derivative Contracts	The gross fair value of the Company's outstanding derivative contracts at the end of each period was as follows: (in thousands) March 31, 2017 September 30, 2017 Derivative Assets (1) Non-designated hedges $ 86 $ 310 Cash flow hedges 2,034 505 Total Derivative Assets $ 2,120 $ 815 Derivative Liabilities (2) Non-designated hedges $ 286 $ 339 Cash flow hedges 1,109 4,346 Total Derivative Liabilities $ 1,395 $ 4,685 (1) Short-term derivative assets are recorded in "other current assets" and long-term derivative assets are recorded in "deferred tax and other assets". As of September 30, 2017 the portion of derivative assets classified as long-term was immaterial. (2) Short-term derivative liabilities are recorded in "accrued liabilities" and long-term derivative liabilities are recorded in "other long-term liabilities". As of September 30, 2017 the portion of derivative liabilities classified as long-term was immaterial.
Notional Value of Outstanding Foreign Exchange Currency Contracts	The following table summarizes the notional value of the Company’s outstanding foreign exchange currency contracts and approximate U.S. Dollar ("USD") equivalent at September 30, 2017 : (in thousands) Local Currency USD Equivalent Position Maturity EUR € 33,900 $ 28,650 Sell EUR 1 month GBP £ 5,000 $ 6,710 Sell GBP 1 month AUD A$ 13,200 $ 10,352 Sell AUD 1 month CAD C$ 2,700 $ 2,161 Sell CAD 1 month
Effect of Non-Designated Derivative Contracts Recognized in Interest and Other Income, Net	The effect of non-designated derivative contracts recognized in other non-operating income and (expense), net in the condensed consolidated statements of operations was as follows: Three Months Ended Six Months Ended (in thousands) 2016 2017 2016 2017 Gain (loss) on foreign exchange contracts $ (193 ) $ 2,102 $ 1,750 $ 5,236
Notional Value of Outstanding Cross-Currency Swaps	The following table summarizes the notional value of the Company’s outstanding MXN cross-currency swaps and approximate USD Equivalent at September 30, 2017 : (in thousands) Local Currency USD Equivalent Position Maturity MXN $ 134,150 $ 6,978 Buy MXN Monthly over 9 months
Reclassification out of Accumulated Other Comprehensive Income	The following table presents the pre-tax effects of derivative instruments designated as cash flow hedges on accumulated other comprehensive income and the condensed consolidated statements of operations for the three and six months ended September 30, 2016 and 2017 : Three Months Ended Six Months Ended (in thousands) 2016 2017 2016 2017 Gain (loss) included in AOCI as of beginning of period $ 415 $ (1,744 ) $ (1,106 ) $ 541 Amount of gain (loss) recognized in other comprehensive income (“OCI”) (effective portion) (650 ) (2,302 ) 304 (4,647 ) Amount of gain (loss) reclassified from OCI into net revenues (effective portion) 825 1,131 985 1,149 Amount of gain (loss) reclassified from OCI into cost of revenues (effective portion) (589 ) (174 ) (1,316 ) (132 ) Total amount of gain (loss) reclassified from AOCI to income (loss) (effective portion) 236 957 (331 ) 1,017 Gain (loss) included in AOCI as of end of period $ (471 ) $ (3,089 ) $ (471 ) $ (3,089 )

COMPUTATION OF EARNINGS PER C30

COMPUTATION OF EARNINGS PER COMMON SHARE (Tables)	6 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings per Common Share	The following table sets forth the computation of basic and diluted earnings per common share for the three and six months ended September 30, 2016 and 2017: Three Months Ended Six Months Ended (in thousands, except per share data) 2016 (1) 2017 2016 (1) 2017 Basic earnings per common share: Numerator: Net income $ 20,474 $ 19,953 $ 40,861 $ 38,781 Income allocated to participating securities, basic n/a (597 ) n/a (1,169 ) Net income attributable to common shareholders, basic $ 20,474 $ 19,356 $ 40,861 $ 37,612 Denominator: Weighted average common shares, basic 32,281 32,570 32,269 32,538 Basic earnings per common share $ 0.63 $ 0.59 $ 1.27 $ 1.16 Diluted earnings per common share: Numerator: Net income attributable to common shareholders, basic $ 20,474 $ 19,356 $ 40,861 $ 37,612 Net effect of reallocating undistributed earnings of unvested shareholders n/a 3 n/a 15 Net income attributable to common shareholders, diluted $ 20,474 $ 19,359 $ 40,861 $ 37,627 Denominator: Weighted average common shares-basic 32,281 32,570 32,269 32,538 Dilutive effect of employee equity incentive plans 445 239 596 573 Weighted average common shares, diluted 32,726 32,809 32,865 33,111 Diluted earnings per common share $ 0.63 $ 0.59 $ 1.24 $ 1.14 Potentially dilutive securities excluded from diluted earnings per common share because their effect is anti-dilutive 543 1,389 634 959 (1) As previously disclosed in forms 10-Q and 10-K for Fiscal Year 2017, the two-class method of calculating earnings per share did not have a material impact on the Company's earnings per share calculation for the three and six months ended September 30. 2016; as such, these periods have not been adjusted to reflect the two-class method of calculating earnings per share in the above table.

REVENUE AND MAJOR CUSTOMERS (Ta

REVENUE AND MAJOR CUSTOMERS (Tables)	6 Months Ended
	Sep. 30, 2017
REVENUE AND MAJOR CUSTOMERS [Abstract]
Net Revenues by Product Group	The following table presents net revenues by product group for the three and six months ended September 30, 2016 and 2017 : Three Months Ended Six Months Ended (in thousands) 2016 2017 2016 2017 Net revenues from unaffiliated customers: Enterprise $ 154,542 $ 162,907 $ 310,439 $ 317,512 Consumer 61,641 47,393 128,850 96,714 Total net revenues $ 216,183 $ 210,300 $ 439,289 $ 414,226
Net Revenues by Geography	The following table presents net revenues by geography: Three Months Ended Six Months Ended (in thousands) 2016 2017 2016 2017 Net revenues from unaffiliated customers: U.S. $ 119,062 $ 111,095 $ 247,300 $ 219,905 Europe and Africa 51,422 56,325 105,489 111,141 Asia Pacific 28,588 24,227 54,815 48,111 Americas, excluding U.S. 17,111 18,653 31,685 35,069 Total international net revenues 97,121 99,205 191,989 194,321 Total net revenues $ 216,183 $ 210,300 $ 439,289 $ 414,226

BASIS OF PRESENTATION (Details)

BASIS OF PRESENTATION (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Mar. 31, 2017
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income tax expense (benefit)	$ 4,772	$ 5,565	$ 2,995	$ 11,493
Out-of-Period Error Resulting in Overstatement of Income Tax Expense [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income tax expense (benefit)	$ (2,800)
Out-of-Period Error Resulting in Overstatement of Income Tax Expense [Member] | Restatement Adjustment [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income tax expense (benefit)					$ 2,800

RECENT ACCOUNTING PRONOUNCEME33

RECENT ACCOUNTING PRONOUNCEMENTS (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Apr. 01, 2017
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Deferred revenue				$ 1,900
Excess tax benefits	$ 100	$ 2,000
Reduction in effective tax rate due to adoption of accounting standard	0.30%	4.80%
Amount reclassified out of financing activities		$ 48,118	$ 39,409
Amount reclassified into operating activities		$ 49,293	66,752
Accounting Standards Update 2016-09 [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Amount reclassified out of financing activities			900
Amount reclassified into operating activities			$ 900

CASH, CASH EQUIVALENTS, AND I34

CASH, CASH EQUIVALENTS, AND INVESTMENTS (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Mar. 31, 2016
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	$ 303,116	$ 301,970	$ 244,455	$ 235,266
Short-term investments (due in 1 year or less)	197,278	178,179
Long-term investments (due in 1 to 3 years)	105,251	127,176
Total cash, cash equivalents and investments measured at fair value, amortized cost	605,157	607,374
Total cash, cash equivalents and investments measured at fair value, gross unrealized gains	815	439
Total cash, cash equivalents and investments measured at fair value, gross unrealized losses	(327)	(488)
Total cash, cash equivalents and investments measured at fair value, fair value	605,645	607,325
Cash [Member]
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	290,429	295,877
Level 1 [Member]
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	0	0
Available-for-sale Securities, amortized cost basis	46,465	48,039
Available-for-sale Securities, gross unrealized gains	675	352
Available-for-sale Securities, gross unrealized losses	(93)	(100)
Available-for-sale Securities, fair value	47,047	48,291
Short-term investments (due in 1 year or less)	34,239	29,959
Long-term investments (due in 1 to 3 years)	12,808	18,332
Level 1 [Member] | Mutual Funds [Member]
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	0	0
Available-for-sale Securities, amortized cost basis	13,507	12,079
Available-for-sale Securities, gross unrealized gains	675	352
Available-for-sale Securities, gross unrealized losses	(27)	(32)
Available-for-sale Securities, fair value	14,155	12,399
Short-term investments (due in 1 year or less)	14,155	12,399
Long-term investments (due in 1 to 3 years)	0	0
Level 1 [Member] | US Treasury Notes [Member]
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	0	0
Available-for-sale Securities, amortized cost basis	32,958	35,960
Available-for-sale Securities, gross unrealized gains	0	0
Available-for-sale Securities, gross unrealized losses	(66)	(68)
Available-for-sale Securities, fair value	32,892	35,892
Short-term investments (due in 1 year or less)	20,084	17,560
Long-term investments (due in 1 to 3 years)	12,808	18,332
Level 2 [Member]
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	12,687	6,093
Available-for-sale Securities, amortized cost basis	268,263	263,458
Available-for-sale Securities, gross unrealized gains	140	87
Available-for-sale Securities, gross unrealized losses	(234)	(388)
Available-for-sale Securities, fair value	268,169	263,157
Short-term investments (due in 1 year or less)	163,039	148,220
Long-term investments (due in 1 to 3 years)	92,443	108,844
Level 2 [Member] | Government Agency Securities [Member]
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	0	0
Available-for-sale Securities, amortized cost basis	47,851	54,415
Available-for-sale Securities, gross unrealized gains	0	20
Available-for-sale Securities, gross unrealized losses	(139)	(164)
Available-for-sale Securities, fair value	47,712	54,271
Short-term investments (due in 1 year or less)	26,870	15,309
Long-term investments (due in 1 to 3 years)	20,842	38,962
Level 2 [Member] | Commercial Paper [Member]
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	11,185	6,093
Available-for-sale Securities, amortized cost basis	52,099	47,152
Available-for-sale Securities, gross unrealized gains	0	0
Available-for-sale Securities, gross unrealized losses	0	0
Available-for-sale Securities, fair value	52,099	47,152
Short-term investments (due in 1 year or less)	40,914	41,059
Long-term investments (due in 1 to 3 years)	0	0
Level 2 [Member] | Corporate Bonds [Member]
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	0	0
Available-for-sale Securities, amortized cost basis	146,781	141,508
Available-for-sale Securities, gross unrealized gains	126	64
Available-for-sale Securities, gross unrealized losses	(95)	(224)
Available-for-sale Securities, fair value	146,812	141,348
Short-term investments (due in 1 year or less)	78,730	73,676
Long-term investments (due in 1 to 3 years)	68,082	67,672
Level 2 [Member] | Certificates of Deposit [Member]
Schedule of Cash, Cash Equivalents and Investments [Line Items]
Cash and cash equivalents	1,502	0
Available-for-sale Securities, amortized cost basis	21,532	20,383
Available-for-sale Securities, gross unrealized gains	14	3
Available-for-sale Securities, gross unrealized losses	0	0
Available-for-sale Securities, fair value	21,546	20,386
Short-term investments (due in 1 year or less)	16,525	18,176
Long-term investments (due in 1 to 3 years)	$ 3,519	$ 2,210

DEFERRED COMPENSATION (Details)

DEFERRED COMPENSATION (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Mar. 31, 2016
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Bank deposits held	$ 303,116	$ 301,970	$ 244,455	$ 235,266
Other long-term liabilities [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred compensation liability, noncurrent	15,500	13,700
Short-term investments [Member] | Mutual Funds [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Investments	14,200	12,400
Bank Time Deposits [Member] | Cash and Cash Equivalents [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Bank deposits held	$ 800	$ 800

DETAILS OF CERTAIN BALANCE SH36

DETAILS OF CERTAIN BALANCE SHEET ACCOUNTS - Accounts Receivable, net (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Mar. 31, 2017
Accounts receivable, net [Line Items]
Accounts receivable	$ 186,870	$ 184,068
Accounts receivable, net	139,683	141,177
Provision for returns [Member]
Accounts receivable, net [Line Items]
Accounts receivable, reserves	(9,865)	(10,541)
Provision for promotions, rebates and other [Member]
Accounts receivable, net [Line Items]
Accounts receivable, reserves	(36,513)	(31,747)
Provisions for doubtful accounts and sales allowances [Member]
Accounts receivable, net [Line Items]
Accounts receivable, reserves	$ (809)	$ (603)

DETAILS OF CERTAIN BALANCE SH37

DETAILS OF CERTAIN BALANCE SHEET ACCOUNTS - Inventory, net (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Mar. 31, 2017
Inventory, Net [Abstract]
Raw materials	$ 22,668	$ 20,260
Work in process	237	215
Finished goods	38,094	34,981
Inventory, net	$ 60,999	$ 55,456

DETAILS OF CERTAIN BALANCE SH38

DETAILS OF CERTAIN BALANCE SHEET ACCOUNTS - Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Mar. 31, 2017	May 31, 2015
Accrued Liabilities [Abstract]
Employee compensation and benefits	$ 22,278	$ 36,415
Accrued interest on 5.50% Senior Notes	10,312	10,407
Warranty obligation	6,739	6,863
VAT/Sales tax payable	5,852	5,433
Derivative liabilities	4,588	1,323
Accrued other	18,665	13,844
Accrued liabilities	$ 68,434	$ 74,285
5.50% Senior Notes [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Stated interest rate of debt instrument	5.50%		5.50%

DETAILS OF CERTAIN BALANCE SH39

DETAILS OF CERTAIN BALANCE SHEET ACCOUNTS - Warranty Obligation (Details) - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Changes in the Warranty Obligation [Roll Forward]
Warranty obligation at beginning of period	$ 8,697	$ 8,537
Warranty provision related to products shipped	4,635	4,649
Deductions for warranty claims processed	(5,080)	(4,742)
Adjustments related to preexisting warranties	405	96
Warranty obligation at end of period	$ 8,657	$ 8,540

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) - USD ($) $ in Millions	Dec. 07, 2016	Sep. 01, 2016	Jul. 06, 2016	Sep. 30, 2017	Sep. 30, 2016
Loss Contingencies [Line Items]
Unconditional purchase obligations				$ 176.2
GN Netcom, Inc. vs. Plantronics, Inc. [Member]
Loss Contingencies [Line Items]
Punitive sanctions awarded against Plantronics, Inc.			$ 3
Accrued amounts					$ 5
GN Netcom, Inc. vs. Plantronics, Inc. [Member] | Punitive Sanctions [Member]
Loss Contingencies [Line Items]
Accrued amounts					3
Payment of punitive damages	$ 1.9	$ 3
GN Netcom, Inc. vs. Plantronics, Inc. [Member] | Estimate of Fees and Costs Incurred [Member]
Loss Contingencies [Line Items]
Accrued amounts					$ 2

DEBT (Details)

DEBT (Details) - USD ($)	May 02, 2016	May 09, 2011	May 31, 2015	Sep. 30, 2017	Mar. 31, 2017
Debt Disclosure [Line Items]
Initiation date of credit agreement		May 9, 2011
Amendment date of Credit Agreement	Apr. 28, 2017
Credit facility expiration date				May 9, 2020
Commitment fee percentage				0.37%
Outstanding borrowings under line of credit				$ 0	$ 0
Minimum required liquid funds				$ 300,000,000
Line Of Credit Facility Interest Rate Spread Below The Banks Announced Prime Rate [Member]
Debt Disclosure [Line Items]
Spread for interest rate				1.20%
Line Of Credit Facility Interest Rate Spread Above A Daily One Month LIBOR Rate [Member]
Debt Disclosure [Line Items]
Spread for interest rate				1.40%
Senior Notes [Member] | 5.50% Senior Notes [Member]
Debt Disclosure [Line Items]
Principal amount of debt issued			$ 500,000,000
Stated interest rate of debt instrument			5.50%	5.50%
Proceeds from issuance of senior notes, net of issuance costs			$ 488,400,000
Debt issuance costs			$ 11,600,000
Debt redemption percentage price, Specified Price			105.50%
Repurchase price, percentage of principal amount			101.00%
Minimum [Member] | Senior Notes [Member] | 5.50% Senior Notes [Member]
Debt Disclosure [Line Items]
Debt redemption notice period			30 days
Maximum [Member] | Senior Notes [Member] | 5.50% Senior Notes [Member]
Debt Disclosure [Line Items]
Debt redemption notice period			60 days
Percentage of debt redeemed			35.00%
Level 2 [Member] | Fair Value [Member] | Senior Notes [Member] | 5.50% Senior Notes [Member]
Debt Disclosure [Line Items]
Long-term debt, 5.50% Senior Notes				$ 520,205,000	505,150,000
Level 2 [Member] | Carrying Value [Member] | Senior Notes [Member] | 5.50% Senior Notes [Member]
Debt Disclosure [Line Items]
Long-term debt, 5.50% Senior Notes				$ 491,784,000	$ 491,059,000
Revolving Credit Facility [Member]
Debt Disclosure [Line Items]
Maximum borrowing capacity of unsecured revolving credit facility	$ 100,000,000

RESTRUCTURING AND OTHER RELAT42

RESTRUCTURING AND OTHER RELATED CHARGES (CREDITS) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)	$ (51)	$ (415)	$ 2,522	$ (1,463)
Totals			4,300
Restructuring Charges [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			2,500
Cost of revenues [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			1,600
Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			200
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			1,400
Employee Severance [Member] | Restructuring Charges [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			1,400
Employee Severance [Member] | Cost of revenues [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			0
Employee Severance [Member] | Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			0
Lease Exit Charge and Asset Impairment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			700
Lease Exit Charge and Asset Impairment [Member] | Restructuring Charges [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			700
Lease Exit Charge and Asset Impairment [Member] | Cost of revenues [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			0
Lease Exit Charge and Asset Impairment [Member] | Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			0
Write-off of Unrecoverable Indirect Tax Asset [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			700
Write-off of Unrecoverable Indirect Tax Asset [Member] | Restructuring Charges [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			0
Write-off of Unrecoverable Indirect Tax Asset [Member] | Cost of revenues [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			700
Write-off of Unrecoverable Indirect Tax Asset [Member] | Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			0
Asset Impairments Related to Previous Operations [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			400
Asset Impairments Related to Previous Operations [Member] | Restructuring Charges [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			400
Asset Impairments Related to Previous Operations [Member] | Cost of revenues [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			0
Asset Impairments Related to Previous Operations [Member] | Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			0
Loss on Asset Sale [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			900
Loss on Asset Sale [Member] | Restructuring Charges [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			0
Loss on Asset Sale [Member] | Cost of revenues [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			900
Loss on Asset Sale [Member] | Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			0
Accelerated Vesting of Restricted Stock [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			200
Accelerated Vesting of Restricted Stock [Member] | Restructuring Charges [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			0
Accelerated Vesting of Restricted Stock [Member] | Cost of revenues [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			0
Accelerated Vesting of Restricted Stock [Member] | Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits)			$ 200
Clarity [Member] | Disposal Group, Held-for-sale, Not Discontinued Operations [Member]
Restructuring Cost and Reserve [Line Items]
Term of lease			12 months
Term of transition services agreement			1 year

STOCK-BASED COMPENSATION (Detai

STOCK-BASED COMPENSATION (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 8,762	$ 7,903	$ 18,018	$ 16,316
Income tax benefit	(2,840)	(2,877)	(7,689)	(5,649)
Total stock-based compensation, net of tax	5,922	5,026	10,329	10,667
Cost of revenues [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	890	778	1,792	1,620
Research, development, and engineering [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	2,008	2,408	4,109	4,892
Selling, general, and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	5,864	4,717	12,117	9,804
Stock-based compensation expense included in operating expenses [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 7,872	$ 7,125	$ 16,226	$ 14,696

COMMON STOCK REPURCHASES (Detai

COMMON STOCK REPURCHASES (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Equity [Abstract]
Remaining shares authorized for repurchase under program	1,028,586		1,028,586
Shares repurchased			841,249	613,021
Total cost of shares repurchased			$ 39,222	$ 26,828
Average cost per share of shares repurchased (in dollars per share)	$ 46.62	$ 43.76
Value of shares withheld in satisfaction of employee tax withholding obligations			$ 10,789	$ 9,123

ACCUMULATED OTHER COMPREHENSI45

ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands		Sep. 30, 2017	Mar. 31, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated unrealized gain (loss) on cash flow hedges	[1]	$ (3,039)	$ 529
Accumulated foreign currency translation adjustments		4,685	4,428
Accumulated unrealized gain (loss) on investments		(115)	(263)
Accumulated other comprehensive income		$ 1,531	$ 4,694
[1]	Refer to Note 12, Foreign Currency Derivatives, which discloses the nature of the Company's derivative assets and liabilities as of March 31, 2017 and September 30, 2017.

FORIEGN CURRENCY DERIVATIVES (D

FORIEGN CURRENCY DERIVATIVES (Details) MXN in Thousands, $ in Thousands	6 Months Ended
	Sep. 30, 2017USD ($)financial_institution	Sep. 30, 2017MXNfinancial_institution	Mar. 31, 2017MXN
Derivative [Line Items]
Number of financial institutions company has International Swap and Derivatives Association agreements	4	4
Foreign currency swap contract [Member]
Derivative [Line Items]
Notional amount of contracts	$ 6,978	MXN 134,150	MXN 287,200
Cash flow hedges [Member] | Options [Member] | Minimum [Member]
Derivative [Line Items]
Term of derivative contract	6 months
Cash flow hedges [Member] | Options [Member] | Maximum [Member]
Derivative [Line Items]
Term of derivative contract	11 months
Cash flow hedges [Member] | Forwards [Member]
Derivative [Line Items]
Term of derivative contract	3 months

FOREIGN CURRENCY DERIVATIVES (D

FOREIGN CURRENCY DERIVATIVES (Details 1) - USD ($) $ in Thousands	Sep. 30, 2017	Mar. 31, 2017
Derivative [Line Items]
Total Derivative Liabilities	$ 4,588	$ 1,323
Other Current Assets [Member]
Derivative [Line Items]
Total Derivative Assets	815	2,120
Other Current Assets [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Total Derivative Assets	310	86
Other Liabilities [Member]
Derivative [Line Items]
Total Derivative Liabilities	4,685	1,395
Other Liabilities [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Total Derivative Liabilities	339	286
Cash flow hedges [Member] | Other Current Assets [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Total Derivative Assets	505	2,034
Cash flow hedges [Member] | Other Liabilities [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Total Derivative Liabilities	$ 4,346	$ 1,109

FOREIGN CURRENCY DERIVATIVES 48

FOREIGN CURRENCY DERIVATIVES (Details 2) - 6 months ended Sep. 30, 2017 € in Thousands, £ in Thousands, CAD in Thousands, AUD in Thousands, $ in Thousands	EUR (€)	CAD	GBP (£)	AUD	USD ($)
Foreign Exchange Forward, EURO [Member]
Derivative [Line Items]
Notional amount of contracts	€ 33,900				$ 28,650
Position	Sell EUR
Maturity	1 month
Foreign Exchange Forward, GBP [Member]
Derivative [Line Items]
Notional amount of contracts			£ 5,000		6,710
Position	Sell GBP
Maturity	1 month
Foreign Exchange Forward, AUD [Member]
Derivative [Line Items]
Notional amount of contracts				AUD 13,200	10,352
Position	Sell AUD
Maturity	1 month
Foreign Exchange Forward, CAD [Member]
Derivative [Line Items]
Notional amount of contracts		CAD 2,700			$ 2,161
Position	Sell CAD
Maturity	1 month

FOREIGN CURRENCY DERIVATIVES 49

FOREIGN CURRENCY DERIVATIVES (Details 3) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain (loss) on foreign exchange contracts	$ 2,102	$ (193)	$ 5,236	$ 1,750

FOREIGN CURRENCY DERIVATIVES 50

FOREIGN CURRENCY DERIVATIVES (Details 4)	Sep. 30, 2017EUR (€)	Sep. 30, 2017GBP (£)	Mar. 31, 2017EUR (€)	Mar. 31, 2017GBP (£)
Foreign Exchange Option [Member]
Derivative [Line Items]
Notional amount of contracts	€ 81,700,000	£ 23,900,000	€ 73,500,000	£ 23,900,000
Foreign Exchange Forward [Member]
Derivative [Line Items]
Notional amount of contracts	€ 13,400,000	£ 3,600,000	€ 11,200,000	£ 3,300,000

FOREIGN CURRENCY DERIVATIVES 51

FOREIGN CURRENCY DERIVATIVES (Details 5) - Foreign currency swap contract [Member] MXN in Thousands, $ in Thousands	6 Months Ended
	Sep. 30, 2017USD ($)	Sep. 30, 2017MXN	Mar. 31, 2017MXN
Derivative [Line Items]
Notional amount of contracts	$ 6,978	MXN 134,150	MXN 287,200
Position	Buy MXN
Maturity	9 months

FOREIGN CURRENCY DERIVATIVES 52

FOREIGN CURRENCY DERIVATIVES (Details 6) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Gain (Loss) Included in Accumulated Other Comprehensive Income [Roll Forward]
Gain (loss) included in AOCI as of beginning of period	$ (1,744)	$ 415	$ 541	$ (1,106)
Amount of gain (loss) recognized in other comprehensive income (“OCI”) (effective portion)	(2,302)	(650)	(4,647)	304
Amount of gain (loss) reclassified from OCI into net revenues (effective portion)	210,300	216,183	414,226	439,289
Amount of gain (loss) reclassified from OCI into cost of revenues (effective portion)	(102,668)	(105,737)	(203,311)	(215,770)
Total amount of gain (loss) reclassified from AOCI to income (loss) (effective portion)	957	236	1,017	(331)
Gain (loss) included in AOCI as of end of period	(3,089)	(471)	(3,089)	(471)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Gain (Loss) Included in Accumulated Other Comprehensive Income [Roll Forward]
Amount of gain (loss) reclassified from OCI into net revenues (effective portion)	1,131	825	1,149	985
Amount of gain (loss) reclassified from OCI into cost of revenues (effective portion)	$ (174)	$ (589)	$ (132)	$ (1,316)

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Effective tax rate	19.30%	21.40%	7.20%	22.00%
Reduction in effective tax rate due to correction to the geographic mix of income			6.60%
Reduction in effective tax rate due to adoption of accounting standard	0.30%		4.80%
Unrecognized tax benefits	$ 13,400,000		$ 13,400,000		$ 12,900,000
Accrued interest related to unrecognized tax benefits	1,600,000		1,600,000		1,700,000
Accrued penalties	$ 0		$ 0		$ 0

COMPUTATION OF EARNINGS PER C54

COMPUTATION OF EARNINGS PER COMMON SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Numerator:
Net income	$ 19,953	$ 20,474	$ 38,781	$ 40,861
Income allocated to participating securities, basic	(597)		(1,169)
Net income attributable to common shareholders, basic	$ 19,356	$ 20,474	$ 37,612	$ 40,861
Denominator:
Weighted average common shares-basic	32,570	32,281	32,538	32,269
Basic earnings per common share (in dollars per share)	$ 0.59	$ 0.63	$ 1.16	$ 1.27
Diluted earnings per common share:
Net effect of reallocating undistributed earnings of unvested shareholders	3		15
Net income attributable to common shareholders, diluted	$ 19,359	$ 20,474	$ 37,627	$ 40,861
Earnings per common share:
Dilutive effect of employee equity incentive plans	239	445	573	596
Weighted average common shares-diluted	32,809	32,726	33,111	32,865
Diluted earnings per common share (in dollars per share)	$ 0.59	$ 0.63	$ 1.14	$ 1.24
Potentially dilutive securities excluded from diluted earnings per common share because their effect is anti-dilutive	1,389	543	959	634

REVENUE AND MAJOR CUSTOMERS (De

REVENUE AND MAJOR CUSTOMERS (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Sep. 30, 2017USD ($)Customer	Sep. 30, 2016USD ($)Customer	Sep. 30, 2017USD ($)Customer	Sep. 30, 2016USD ($)	Mar. 31, 2017Customer	Mar. 31, 2016Customer
Revenue from External Customer [Line Items]
Net revenues	$ 210,300	$ 216,183	$ 414,226	$ 439,289
US [Member]
Revenue from External Customer [Line Items]
Net revenues	111,095	119,062	219,905	247,300
Europe and Africa [Member]
Revenue from External Customer [Line Items]
Net revenues	56,325	51,422	111,141	105,489
Asia Pacific [Member]
Revenue from External Customer [Line Items]
Net revenues	24,227	28,588	48,111	54,815
Americas, excluding U.S. [Member]
Revenue from External Customer [Line Items]
Net revenues	18,653	17,111	35,069	31,685
Total international net revenues [Member]
Revenue from External Customer [Line Items]
Net revenues	99,205	97,121	194,321	191,989
Enterprise [Member]
Revenue from External Customer [Line Items]
Net revenues	162,907	154,542	317,512	310,439
Consumer [Member]
Revenue from External Customer [Line Items]
Net revenues	$ 47,393	$ 61,641	$ 96,714	$ 128,850
Net Revenues [Member] | Customer Concentration Risk [Member] | Ingram Micro [Member]
Revenue from External Customer [Line Items]
Number of major customers, ten percent or greater, net revenues | Customer	1	1				1
Concentration risk percentage	12.40%	10.70%	12.20%	10.40%
Accounts Receivable [Member] | Customer Concentration Risk [Member] | Ingram Micro [Member]
Revenue from External Customer [Line Items]
Number of major customers, ten percent or greater, net accounts receivable | Customer	2		2		1
Concentration risk percentage			15.40%		17.60%
Accounts Receivable [Member] | Customer Concentration Risk [Member] | D&H Distributors [Member]
Revenue from External Customer [Line Items]
Concentration risk percentage			11.50%

SUBSEQUENT EVENTS (Details)

SUBSEQUENT EVENTS (Details) - Subsequent Event [Member]	Nov. 20, 2017$ / shares
Subsequent Event [Line Items]
Dividends declared date	Oct. 31, 2017
Cash dividend payable per share (in dollars per share)	$ 0.15
Dividend payable date	Dec. 8, 2017
Date of stockholders on record for dividends declared	Nov. 20, 2017