Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities:
Net loss	$ (160,419,000)	$ (71,801,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation, amortization and impairment charges	7,461,000	3,593,000
Amortization of premium on marketable securities	33,000
Stock-based compensation	12,289,000	5,954,000
Deferred executive compensation expense	2,264,000	1,194,000
Revaluation of warrant liability	15,924,000	26,629,000
Increase (decrease) from:
Other current assets	(3,416,000)	(398,000)
Amounts due under license agreements	(43,000)	343,000
Other assets	(1,891,000)	(4,000)
Accounts payable	2,381,000	1,601,000
Accrued compensation and benefits	4,858,000	(326,000)
Accrued product development expenses	1,389,000	661,000
Other accrued expenses	2,896,000	1,675,000
Other liabilities	4,920,000
Deferred revenue	(173,000)	1,056,000
Deferred executive compensation paid	(1,063,000)	(775,000)
Net cash provided by (used in) operating activities	(112,590,000)	(30,598,000)
Cash flows from investing activities:
Acquisitions of marketable securities	(89,554,000)
Proceeds from maturities of marketable securities	24,500,000
Change in restricted cash	(288,000)
Investment in property and equipment	(3,054,000)	(1,147,000)
Investment in intangible assets	(628,000)	(563,000)
Net cash used in investing activities	(69,024,000)	(1,710,000)
Cash flows from financing activities:
Proceeds from borrowing of long-term debt		4,375,000
Repayment of long-term borrowings	(1,050,000)	(1,050,000)
Principal payments under capital lease obligation	(42,000)	(51,000)
Proceeds from issuance of common stock, pursuant to warrants	12,482,000	8,079,000
Proceeds from issuance of common stock pursuant to stock option and purchase plans	8,202,000	4,469,000
Payment of tax withholding obligations related to stock compensation	(2,615,000)	(827,000)
Net cash provided by financing activities	16,977,000	14,995,000
Net increase (decrease) in cash and cash equivalents	(164,637,000)	(17,313,000)
Cash and cash equivalents, beginning of period	306,256,000	103,630,000
Cash and cash equivalents, end of period	$ 141,619,000	$ 86,317,000