Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities:
Net loss	$ (15,669)	$ (45,426)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization of debt discounts	7,734	7,234
Stock-based compensation	9,197	9,932
Realized gain on marketable securities	(15)
Changes in operating assets and liabilities:
Accounts receivable	42,910	(6,595)
Prepaid expenses and other assets	(837)	29
Inventory	(577)	23
Accounts payable	1,554	(1,765)
Accrued and other current liabilities	(2,820)	(4,776)
Deferred revenue - Product revenues		3,673
Deferred revenue - Collaborative agreements	(16,739)	(16,730)
Net cash provided by (used in) operating activities	24,738	(54,401)
Cash flows from investing activities:
Capital expenditures	(894)	(496)
Sales and maturities of marketable securities	136	167
Net cash used in investing activities	(758)	(329)
Cash flows from financing activities:
Proceeds from issuance of common stock under stock plans	17,777	13,421
Net cash provided by financing activities	17,777	13,421
Net increase (decrease) in cash and cash equivalents	41,757	(41,309)
Cash and cash equivalents at beginning of period	224,057	273,164
Cash and cash equivalents at end of period	$ 265,814	$ 231,855