CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Net sales	$ 1,257,158	$ 719,691	$ 2,049,052	$ 1,363,916
Cost of goods sold	684,599	444,344	1,167,237	846,322
Amortization of intangible assets and purchase accounting effect on inventory	2,836	3,271	6,359	6,542
Gross profit	569,723	272,076	875,456	511,052
Operating expenses:
Marketing and selling	158,797	134,155	292,035	257,188
Research and development	53,379	41,964	103,104	84,207
General and administrative	31,664	24,048	60,735	46,207
Amortization of intangible assets and acquisition-related costs	4,331	4,218	8,940	7,814
Change in fair value of contingent consideration for business acquisition	0	0	5,716	0
Restructuring charges (credits), net	(1)	(364)	(54)	114
Total operating expenses	248,170	204,021	470,476	395,530
Operating income	321,553	68,055	404,980	115,522
Interest income	513	2,390	1,133	4,943
Other income (expense), net	1,149	(110)	3,178	1,751
Income before income taxes	323,215	70,335	409,291	122,216
Provision for (benefit from) income taxes	56,301	(2,598)	70,304	3,938
Net income	$ 266,914	$ 72,933	$ 338,987	$ 118,278
Net income per share:
Basic (in dollars per share)	$ 1.58	$ 0.44	$ 2.02	$ 0.71
Diluted (in dollars per share)	$ 1.56	$ 0.43	$ 1.99	$ 0.70
Weighted average shares used to compute net income per share:
Basic (in shares)	168,645	166,662	168,140	166,484
Diluted (in shares)	171,382	169,027	170,766	168,914