Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income	$ 2,107,457	$ 593,576
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation expense	332,434	268,898
Depreciation expense	80,160	80,685
Increase in fair value of contingent consideration	12,600	2,959
Deferred income taxes	65,110	94,175
Gains on equity securities	(140,866)	(68,862)
Other non-cash items, net	52,371	(4,024)
Changes in operating assets and liabilities:
Accounts receivable, net	(151,191)	(41,444)
Inventories	(94,907)	(45,280)
Prepaid expenses and other assets	(264,909)	(23,709)
Accounts payable	16,153	(12,210)
Accrued expenses	451,084	255,699
Other liabilities	296,477	22,859
Net cash provided by operating activities	2,761,973	1,123,322
Cash flows from investing activities:
Purchases of available-for-sale debt securities	(246,937)	(381,739)
Maturities of available-for-sale debt securities	184,419	375,145
Sale of equity securities	149,595	0
Payment to acquire business, net of cash acquired	0	(245,824)
Expenditures for property and equipment	(212,109)	(58,690)
Investment in equity securities	(19,327)	(27,219)
Net cash used in investing activities	(144,359)	(338,327)
Cash flows from financing activities:
Issuances of common stock under benefit plans	234,854	144,630
Repurchases of common stock	(408,033)	(150,017)
Payments in connection with common stock withheld for employee tax obligations	(179,775)	(5,936)
Payments on finance leases	(31,378)	(28,879)
Proceeds related to finance leases	8,642	1,002
Advance from collaborator	5,000	10,000
Repayments of advanced funding	(2,741)	(4,316)
Other financing activities	(6,658)	(1,132)
Net cash used in financing activities	(380,089)	(34,648)
Effect of changes in exchange rates on cash	2,779	(4,009)
Net increase in cash and cash equivalents	2,240,304	746,338
Cash, cash equivalents and restricted cash—beginning of period	3,120,681	2,658,253
Cash, cash equivalents and restricted cash—end of period	5,360,985	3,404,591
Supplemental disclosure of cash flow information:
Cash paid for interest	40,769	41,704
Cash paid for income taxes	81,684	22,838
Issuances of common stock from employee benefit plans receivable	45	13
Accrued share repurchase liability	$ 0	$ 12,001