CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income	$ 477,980	$ 248,931
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	36,358	38,115
Non-cash compensation expense	82,422	133,789
Other non-cash charges and expenses, net	(4,193)	3,956
Deferred taxes	(6,366)	(40,988)
Changes in assets and liabilites
Decrease (increase) in Sanofi, Bayer, and trade accounts receivable	30,408	(137,928)
Increase in Inventories	(88,760)	(69,744)
Decrease (increase) in prepaid expenses and other assets	68,836	(20,325)
(Decrease) increase in deferred revenue	(54,596)	12,400
Increase in accounts payable, accrued expenses and other liabilities	76,654	187,695
Total adjustments	140,763	106,970
Net cash provided by operating activities	618,743	355,901
Cash flows from investing activities:
Purchases of marketable securities	(601,313)	(208,694)
Sales or maturities of marketable securities	255,276	119,012
Capital expenditures	(79,375)	(50,461)
Net cash used in investing activities	(425,412)	(140,143)
Cash flows from financing activities:
Proceeds in connection with capital and facility lease obligations	0	57,000
Payments in connection with capital and facility lease obligations	0	(12,861)
Proceeds from issuance of Common Stock	13,427	16,673
Net cash provided by financing activities	13,427	60,812
Net increase in cash, cash equivalents, and restricted cash	206,758	276,570
Cash, cash equivalents, and restricted cash at beginning of period	825,233	547,703
Cash, cash equivalents, and restricted cash at end of period	$ 1,031,991	$ 824,273