Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended		398 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Cash flows from operating activities:
Net loss	$ (103,165)	$ (59,220)	$ (534,416)
Adjustments to reconcile net loss to net cash flows used in operating activities:
Depreciation and amortization	998	1,090	22,968
Loss on disposal of property and equipment	460	182	3,096
Realized gain on sale of short-term securities - available-for-sale			(3,863)
Write-down of short-term securities - available-for-sale			17,001
Impairment charge on real estate owned			1,445
Stock-based compensation	7,476	1,840	39,549
Acquired in-process research and development			29,461
Increase on warrant liability	46,011	40,154	112,979
Changes in operating assets and liabilities:
Net increase in accounts receivable, other current assets and other assets	(520)	(1,162)	(9,281)
Net increase (decrease) in accounts payable, accrued employee compensation, and other liabilities	1,867	(5,420)	14,280
Net cash used in operating activities	(46,873)	(22,536)	(306,781)
Cash flows from investing activities:
Purchase of restricted investments	(7,807)		(7,807)
Purchase of property and equipment	(1,762)	(108)	(21,749)
Patent costs	(1,281)	(614)	(11,810)
Purchase of marketable securities			(112,993)
Sale of marketable securities			117,724
Acquisition costs			(2,389)
Net cash used in investing activities	(10,850)	(722)	(39,024)
Cash flows from financing activities:
Proceeds from sale of common stock, warrants, and partnership units, net of offering costs, and exercise of options and warrants	143,951	21,405	620,510
Repayments of long-term debt	(67)	(64)	(497)
Other financing activities, net	(178)		(564)
Net cash provided by financing activities	143,706	21,341	619,449
Increase (decrease) in cash and cash equivalents	85,983	(1,917)	273,644
Cash and cash equivalents:
Beginning of period	187,661	39,904
End of period	273,644	37,987	273,644
Supplemental disclosure of cash flow information:
Cash paid for interest	123	65	698
Supplemental schedule of noncash investing activities and financing activities:
Short-term securities - available-for-sale received in connection with the private offering			17,897
Issuance of common stock in satisfaction of warrant liabilities	75,210	391	108,044
Tenant improvements paid by landlord	3,692		3,692
Building
Supplemental schedule of noncash investing activities and financing activities:
Issuance of common stock			750
Assumption of long-term debt			2,200
Other Assets
Supplemental schedule of noncash investing activities and financing activities:
Issuance of common stock			8,075
Assumption of long-term debt			$ 2,124