CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net income	$ 1,029,392	$ 636,675
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	70,000	73,241
Non-cash compensation expense	189,217	255,047
Other non-cash items, net	(54,980)	37,631
Deferred taxes	(15,487)	(57,737)
Changes in assets and liabilities:
Increase in Sanofi, Bayer, and trade accounts receivable	(64,907)	(232,927)
Increase in inventories	(182,100)	(151,544)
Decrease (increase) in prepaid expenses and other assets	59,432	(77,168)
Increase (decrease) in deferred revenue	(84,238)	(10,655)
Increase (decrease) in accounts payable, accrued expenses, and other liabilities	66,979	(147,232)
Total adjustments	(16,084)	(311,344)
Net cash provided by operating activities	1,013,308	325,331
Cash flows from investing activities:
Purchases of marketable and other securities	(1,181,205)	(477,408)
Sales or maturities of marketable securities	462,212	272,166
Capital expenditures	(191,392)	(105,310)
Net cash used in investing activities	(910,385)	(310,552)
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	(19,925)
Proceeds from issuance of Common Stock	34,073	188,693
Payments in connection with Common Stock tendered for employee tax obligations	(31,853)	(31,437)
Net cash provided by financing activities	2,220	194,331
Net increase in cash, cash equivalents, and restricted cash	105,143	209,110
Cash, cash equivalents, and restricted cash at beginning of period	825,233	547,703
Cash, cash equivalents, and restricted cash at end of period	$ 930,376	$ 756,813