Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating activities:
Net income	$ 106,801	$ 101,994
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	11,137	9,052
Bad debt (recoveries) expense	(373)	152
Stock-based compensation	20,863	26,445
Write-down of inventory and other	3,122	2,157
Accretion on marketable securities	473	(2,276)
Change in fair value of other investments	(33,872)	5,943
Deferred tax provision	14,187	10,195
Change in fair value of contingent consideration	2,117	661
Other non-cash operating activities	2,008	2,177
Changes in assets and liabilities:
Accounts receivable	4,767	(3,828)
Inventories	6,071	(12,204)
Prepaid expenses and other assets	1,744	(4,077)
Accounts payable	(10,128)	781
Accrued expenses and other liabilities	(21,988)	(1,268)
Deferred revenue	2,039	2,983
Net cash provided by operating activities	108,968	138,887
Investing activities:
Purchases of marketable securities	(294,558)	(268,485)
Proceeds from the sale and maturity of marketable securities and other	220,197	262,881
Purchases of other investments and intangible assets	(3,100)	(7,800)
Acquisition of Breethe Inc., net of cash acquired	(52,183)
Proceeds from sales of Shockwave Medical securities	67,882
Purchases of property and equipment	(19,552)	(24,607)
Net cash used for investing activities	(81,314)	(38,011)
Financing activities:
Proceeds from the exercise of stock options	5,555	2,706
Taxes paid related to net share settlement upon vesting of stock awards	(10,934)	(41,206)
Repurchase of common stock	(11,310)	(34,873)
Proceeds from the issuance of stock under employee stock purchase plan	1,978	2,368
Net cash used for financing activities	(14,711)	(71,005)
Effect of exchange rate changes on cash and cash equivalents	(3,043)	(613)
Net increase in cash and cash equivalents	9,900	29,258
Cash and cash equivalents at beginning of period	192,341	121,021
Cash and cash equivalents at end of period	202,241	150,279
Supplemental disclosure of cash flow information:
Cash paid for income taxes	25,254	6,349
Supplemental disclosure of non-cash activities:
Contingent consideration related to the acquisition of Breethe, Inc.	13,300
Property and equipment in accounts payable and accrued expenses	1,244	3,825
Right-of-use assets obtained in exchange for lease liabilities	$ 193	$ 14,513