REVENUE FROM CONTRACTS WITH CUSTOMERS (Income Statement) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	$ 1,248,738	$ 480,840	$ 2,129,387	$ 1,342,618
Cost of goods sold	898,484	267,983	1,264,730	709,100
Gross profit	350,254	212,857	864,657	633,518
Selling and marketing	161,322	79,513	313,793	208,641
General and administrative	70,638	65,951	205,693	187,378
Research and development	62,305	49,977	173,582	142,245
Depreciation and amortization	10,140	7,864	29,151	34,490
Business reorganization	(5,930)	700	(6,172)	13,012
Total operating expenses	298,475	204,005	716,047	585,766
Income from operations	51,779	8,852	148,610	47,752
Interest and other, net	8,071	3,374	19,647	(2,403)
Income before income taxes	59,850	12,226	168,257	45,349
Benefit from income taxes	120,098	12,914	108,750	37,331
Net income	$ 179,948	$ 25,140	$ 277,007	$ 82,680	[1]
Basic earnings (loss) per share (in dollars per share)	$ 1.59	$ 0.22	$ 2.44	$ 0.76
Diluted earnings (loss) per share (in dollars per share)	$ 1.57	$ 0.21	$ 2.41	$ 0.74
Amounts without adoption of New Revenue Accounting Standard
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	$ 486,563		$ 1,345,985
Cost of goods sold	603,170		953,742
Gross profit	(116,607)		392,243
Selling and marketing	161,322		313,793
General and administrative	70,638		205,693
Research and development	62,305		173,582
Depreciation and amortization	10,140		29,151
Business reorganization	(5,930)		(6,172)
Total operating expenses	298,475		716,047
Income from operations	(415,082)		(323,804)
Interest and other, net	7,808		18,757
Income before income taxes	(407,274)		(305,047)
Benefit from income taxes	176,570		208,210
Net income	$ (230,704)		$ (96,837)
Basic earnings (loss) per share (in dollars per share)	$ (2.03)		$ 0
Diluted earnings (loss) per share (in dollars per share)	(2.03)		0
Increase (decrease) due to adoption of New Revenue Accounting Standard
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Diluted earnings (loss) per share (in dollars per share)	$ 3.60		$ 3.26
Increase (decrease) due to adoption of New Revenue Accounting Standard | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	$ 762,175		$ 783,402
Cost of goods sold	295,314		310,988
Gross profit	466,861		472,414
Selling and marketing	0		0
General and administrative	0		0
Research and development	0		0
Depreciation and amortization	0		0
Business reorganization	0		0
Total operating expenses	0		0
Income from operations	466,861		472,414
Interest and other, net	263		890
Income before income taxes	467,124		473,304
Benefit from income taxes	(56,472)		(99,460)
Net income	$ 410,652		$ 373,844
Basic earnings (loss) per share (in dollars per share)	$ 3.62		$ 3.29

[1] Prior period amounts have been adjusted retrospectively to reflect the adoption of ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. Refer to Note 1 for further discussion.