Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended		395 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013
Cash flows from operating activities:
Net loss	$ (61,135)	$ (9,666)	$ (492,386)
Adjustments to reconcile net loss to net cash flows used in operating activities:
Depreciation and amortization	711	715	22,681
Loss on disposal of property and equipment	334	123	2,970
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	3,989	1,148	36,062
Acquired in-process research and development			29,461
Increase (decrease) on warrant liability	28,851	(2,562)	95,819
Net (increase) decrease in accounts receivable, other current assets and other assets	549	(3,537)	(8,212)
Net increase (decrease) in accounts payable, accrued employee compensation, and other liabilities	(294)	(952)	12,119
Net cash used in operating activities	(26,995)	(14,731)	(286,903)
Cash flows from investing activities:
Purchase of restricted investments	(7,807)		(7,807)
Purchase of property and equipment	(435)	(143)	(20,422)
Patent costs	(931)	(498)	(11,460)
Purchase of marketable securities			(112,993)
Sale of marketable securities			117,724
Acquisition costs			(2,389)
Net cash used in investing activities	(9,173)	(641)	(37,347)
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	4,915	1	481,474
Repayments of long-term debt	(45)	(42)	(475)
Other financing activities, net	(178)		(654)
Net cash provided by (used in) financing activities	4,692	(41)	480,435
Increase (decrease) in cash and cash equivalents	(31,476)	(15,413)	156,185
Cash and cash equivalents:
Beginning of period	187,661	39,904
End of period	156,185	24,491	156,185
Supplemental disclosure of cash flow information:
Cash paid during the year for interest	102	43	677
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 and warrants in satisfaction of liabilities	14,928		47,762
Receivable for warrants exercised	2,624		2,624
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