Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash flows from operating activities
Net loss	$ (9,277)	$ (11,049)
Loss from discontinued operations		1,334
Loss from continuing operations	(9,277)	(9,715)
Adjustments to reconcile loss from continuing operations to net cash used in operating activities:
Gain on sale of property and equipment		(25)
Change in fair value of warrant liability	328	(27)
Unrealized gain on marketable securities	8	2
Depreciation and amortization	225	208
Amortization of deferred financing costs	83	39
Stock-based compensation expense	52	(140)
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(158)	(1,570)
Accounts payable and accrued expenses	(1,387)	(846)
Interest payable	133	138
Deferred revenue	(58)
Other non-current liabilities	(17)	386
Net cash used in operating activities from continuing operations	(10,068)	(11,550)
Net cash provided by operating activities from discontinued operations		1,749
Net cash used in operating activities	(10,068)	(9,801)
Cash flows from investing activities
Purchases of marketable securities	(21,806)	(13,848)
Sales and maturities of marketable securities	293	8,349
Purchases of property and equipment, net	(40)	(203)
Net cash used in investing activities from continuing operations	(21,553)	(5,702)
Net cash used in investing activities	(21,553)	(5,702)
Cash flows from financing activities
Proceeds from issuance of common stock	49
Proceeds from issuance of secured notes payable		15,000
Repayment of secured notes payable	(437)
Deferred financing costs	(669)	(656)
Net cash provided by (used in) financing activities from continuing operations	(1,057)	14,344
Net cash used in financing activities from discontinued operations		(1,739)
Net cash provided by (used in) financing activities	(1,057)	12,605
Net change in cash and cash equivalents	(32,678)	(2,898)
Cash and cash equivalents at beginning of period	48,544	23,741
Cash and cash equivalents at end of period	15,866	20,843
Supplemental cash flow information:
Cash paid for interest-Continuing operations	688	165
Cash paid for interest-Discontinued operations		$ 3,032