CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017		Sep. 30, 2016
Cash flows from operating activities:
Net income (loss)	$ (163,513)		$ 95,349
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Depreciation and amortization	39,319		40,859
In-process research and development impairment	12,000
Stock-based compensation	99,287		68,598
Expense related to senior note conversions	54,881
Other, net	216		325
Unrealized loss (gain) on long term investment	2,343		(20,497)
Change in fair value of acquisition-related contingent consideration	(1,914)		10,283
Changes in operating assets and liabilities:
Accounts receivable	(49,587)		(6,712)
Prepaid expenses and other assets	(32,051)		(13,323)
Inventory	4,741		4,439
Accounts payable	(5,666)		25,683
Accrued and other liabilities	36,223		15,018
Deferred revenue-collaborative agreements			(9,644)
Net cash (used in) provided by operating activities	(3,721)		210,378
Cash flows from investing activities:
Acquisition of business, net of cash acquired			(142,965)
Purchase of long term investments	(123,891)
Capital expenditures	(85,770)		(104,405)
Purchases of marketable securities	(131,919)		(26,921)
Sale and maturities of marketable securities	134,604		77,815
Net cash used in investing activities	(206,976)		(196,476)
Cash flows from financing activities:
Restricted investments, net	(40)		13,976
Proceeds from issuance of common stock under stock plans	58,554		32,468
Proceeds from issuance of common stock, net	649,387
Cash paid in connection with senior note conversions	(8,934)
Direct financing arrangements repayments			(445)
Payment of contingent consideration	(12,521)		(1,226)
Net cash provided by financing activities	686,446		44,773
Effect of exchange rates on cash and cash equivalents	(46)		(15)
Net increase in cash and cash equivalents	475,703		58,660
Cash and cash equivalents at beginning of period	652,343	[1]	521,439
Cash and cash equivalents at end of period	1,128,046		580,099
Supplemental Schedule of Cash Flow Information
Interest paid	180		3,892
Income taxes paid	6,187		717
Unpaid purchases of property and equipment	10,774		6,989
0.375% Convertible Senior Notes due 2018
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Expense related to senior note conversions	1,400
Supplemental Schedule of Cash Flow Information
Reclassification to common stock and additional paid in capital in connection with conversions or exchange of convertible senior notes	351,041		5
1.25% Convertible Senior Notes due 2020
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Expense related to senior note conversions	5,100
Supplemental Schedule of Cash Flow Information
Reclassification to common stock and additional paid in capital in connection with conversions or exchange of convertible senior notes	$ 330,011		$ 4

[1] The condensed consolidated balance sheet at December 31, 2016 has been derived from the audited financial statements at that date.