Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020
Operating activities:
Net income	$ 136,505	$ 225,525	$ 203,009
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	28,089	24,097	20,430
Acquired in-process research & development	115,986
Bad debt expense (recoveries)	46	(126)	487
Stock-based compensation expense	52,729	47,006	39,781
Write-down of inventory and other	17,993	8,518	4,249
Accretion on marketable securities	3,655	1,977	(2,731)
Change in fair value of investments	(22,873)	(50,983)	5,184
Deferred tax provision	2,413	29,380	32,953
Change in fair value of contingent consideration	(862)	2,406	(575)
Gain on previously held interest in preCARDIA	(20,980)
Other non-cash operating activities	2,885	4,164	4,108
Changes in assets and liabilities:
Accounts receivable, net	5,335	(12,059)	5,551
Inventories, net	(29,323)	2,535	(13,237)
Prepaid expenses and other assets	(8,406)	(1,032)	(5,333)
Accounts payable	641	2,629	2,581
Accrued expenses and other liabilities	(760)	(14,632)	15,676
Deferred revenue	2,317	5,173	2,787
Net cash provided by operating activities	285,390	274,578	314,920
Investing activities:
Purchases of marketable securities	(787,150)	(556,199)	(611,280)
Proceeds from the sale and maturity of marketable securities	543,513	396,643	550,788
Purchases of other investments and intangible assets	(18,769)	(26,104)	(20,957)
Proceeds from sale of Shockwave Medical securities		67,882
Purchases of property and equipment	(35,763)	(53,383)	(44,006)
Net cash used for investing activities	(380,990)	(223,344)	(125,455)
Financing activities:
Proceeds from the exercise of stock options	9,424	9,075	3,748
Taxes paid related to net share settlement upon vesting of stock awards	(16,526)	(11,311)	(41,687)
Payment of Breethe contingent consideration at acquisition date fair value	(2,334)
Repurchase of common stock		(11,310)	(84,879)
Proceeds from the issuance of stock under employee stock purchase plan	7,234	5,479	5,103
Net cash used for financing activities	(2,202)	(8,067)	(117,715)
Effect of exchange rate changes on cash and cash equivalents	(2,090)	(2,798)	(430)
Net (decrease) increase in cash and cash equivalents	(99,892)	40,369	71,320
Cash and cash equivalents at beginning of period	232,710	192,341	121,021
Cash and cash equivalents at end of period	132,818	232,710	192,341
Supplemental disclosure of cash flow information:
Cash paid for income taxes	61,760	48,693	9,685
Supplemental disclosure of non-cash investing and financing activities:
Contingent consideration related to the acquisition of Breethe		13,300
Property and equipment in accounts payable and accrued expenses	1,817	1,638	2,977
Right-of-use assets obtained in exchange for lease liabilities	6,461	2,592	$ 15,650
Precardia [Member]
Investing activities:
Payments for acquisition	$ (82,821)
Breethe
Investing activities:
Payments for acquisition		$ (52,183)