CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016		Jun. 30, 2015
Cash flows from operating activities:
Net income (loss)	$ 58,472		$ (9,063)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation and amortization	23,908		23,101
Stock-based compensation	42,071		35,150
Other, net	251
Unrealized loss (gain) on long term investment	3,804		(27,174)
Excess tax benefit from stock-based compensation			(2,073)
Change in fair value of acquisition-related contingent consideration	2,271
Changes in operating assets and liabilities:
Accounts receivable	(2,818)		(17,189)
Prepaid expenses and other assets	(7,460)		946
Inventory	1,682		(1,009)
Accounts payable	8,883		4,700
Accrued and other liabilities	(9,528)		7,866
Deferred revenue - collaborative agreements	(6,429)		(6,451)
Net cash provided by operating activities	115,107		8,804
Cash flows from investing activities:
Acquisition of business, net of cash acquired	(144,845)
Long term investment			(39,829)
Capital expenditures	(87,776)		(5,749)
Purchases of marketable securities	(17,795)		(80,212)
Sale and maturities of marketable securities	63,892		40,524
Net cash (used in) investing activities	(186,524)		(85,266)
Cash flows from financing activities:
Restricted investments, net	13,987		(273)
Proceeds from issuance of common stock under stock plans	24,105		62,958
Direct financing arrangements repayments	(445)		(912)
Excess tax benefit from stock-based compensation			2,073
Net cash provided by financing activities	37,647		63,846
Effect of exchange rates on cash and cash equivalents	(15)
Net decrease in cash and cash equivalents	(33,785)		(12,616)
Cash and cash equivalents at beginning of period	521,439	[1]	452,297
Cash and cash equivalents at end of period	487,654		439,681
Supplemental Schedule of Cash Flow Information
Interest paid	3,892		1,670
Incomes taxes paid	229		83
4.75% Convertible Senior Notes due 2015
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			$ 45,327
1.25% Convertible Senior Notes due 2020
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	$ 4

[1] The condensed consolidated balance sheet at December 31, 2015 has been derived from the audited financial statements at that date.