CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015		Sep. 30, 2014
Cash flows from operating activities:
Net loss	$ (48,645)		$ (11,538)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization of debt discounts	34,279		29,192
Stock-based compensation	52,775		46,253
Debt exchange expense on senior note conversions			265
Realized gain on marketable securities	(1,830)
Unrealized loss on long term investment	4,115
Excess tax benefit from stock based compensation	(2,094)		(74)
Changes in operating assets and liabilities:
Accounts receivable	(29,033)		(74,225)
Prepaid expenses and other assets	(1,918)		(9,703)
Inventory	(830)		(2,588)
Accounts payable	2,904		7,503
Accrued and other liabilities	16,469		6,102
Deferred revenue - collaborative agreements	(9,665)		(9,651)
Net cash provided by (used in) operating activities	16,527		(18,464)
Cash flows from investing activities:
Long term investment	(39,829)
Capital expenditures	(19,107)		(22,021)
Purchases of marketable securities	(94,376)		(113,281)
Sale and maturities of marketable securities	52,831		381
Net cash used in investing activities	(100,481)		(134,921)
Cash flows from financing activities:
Restricted investments, net	(128)
Proceeds from issuance of common stock under stock plans	76,871		64,151
Direct financing arrangement repayments	(1,379)
Excess tax provision from stock based compensation	2,094		74
Cash paid in connection with exchange of 4.75% convertible senior notes due 2015			(265)
Net cash provided by financing activities	77,458		63,960
Net decrease in cash and cash equivalents	(6,496)		(89,425)
Cash and cash equivalents at beginning of period	452,297	[1]	471,429
Cash and cash equivalents at end of period	445,801		382,004
Supplemental Schedule of Cash Flow Information
Interest paid	7,698		5,245
Incomes taxes paid	86		167
Reclassification to additional paid in capital in connection with conversions or exchanges of 4.75% convertible senior notes due 2015	$ 88,962		4,656
Purchase of property and equipment financed by direct financing lease			$ 26,815

[1] The condensed consolidated balance sheet at December 31, 2014 has been derived from the audited financial statements at that date.