Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flows from operating activities:
Net loss	$ (18,240)	$ (41,389)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization of debt discounts	15,787	14,638
Stock-based compensation	19,130	19,843
Debt exchange expense	9,771
Changes in operating assets and liabilities:
Accounts receivable	43,429	(7,426)
Prepaid expenses and other assets	3,476	8,448
Inventory	(2,790)	(796)
Accounts payable	(490)	(3,837)
Accrued and other current liabilities	(3,775)	(8,350)
Deferred revenue - Product revenues		6,661
Deferred revenue - Collaborative agreements	(33,479)	(33,469)
Net cash provided by (used in) operating activities	32,819	(45,677)
Cash flows from investing activities:
Capital expenditures	(1,447)	(1,503)
Purchases of marketable securities	(15,010)
Sales and maturities of marketable securities	(3)	264
Net cash used in investing activities	(16,460)	(1,239)
Cash flows from financing activities:
Proceeds from issuance of common stock under stock plans	27,557	31,315
Paid in connection with exchange of 4.75% convertible senior notes due 2015	(9,771)
Net cash provided by financing activities	17,786	31,315
Net increase (decrease) in cash and cash equivalents	34,145	(15,601)
Cash and cash equivalents at beginning of period	224,057	273,164
Cash and cash equivalents at end of period	258,202	257,563
Supplemental Schedule of Cash Flow Information
Interest paid	9,500	9,500
Income taxes paid	140	1
Non-cash reclassification to additional paid in capital in connection with exchange of 4.75% convertible senior notes due 2015	$ 118,593