Condensed Consolidated Statement of Cash Flows (unaudited) (USD $) In Thousands	9 Months Ended		111 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011
Cash Flows from Operating Activities:
Net loss	$ (12,996)	$ (11,905)	$ (77,200)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	188	139	1,098
Amortization	36	23	71
Accretion of discount on investment securities	0	(2)	(461)
Stock-based compensation	1,683	1,453	11,318
Non-cash interest expense	91	60	182
Non-cash interest income	(12)	0	(12)
Gain on derivative instruments	(563)	0	(563)
(Increase) decrease in prepaid expenses and other current assets	(505)	464	(1,327)
Increase (decrease) in accounts payable, accrued expenses and deferred rent	289	555	3,851
Loss on disposal of fixed assets	0	0	23
Net cash used in operating activities	(11,789)	(9,213)	(63,020)
Cash Flows from Investing Activities:
Cash paid for property and equipment	(183)	(48)	(1,446)
Purchases of investments	0	(5,448)	(39,489)
Proceeds from maturities of investments	0	1,900	38,301
Net cash used in investing activities	(183)	(3,596)	(2,634)
Cash Flows from Financing Activities:
Proceeds from issuance of stock, net of financing costs	18,451	(106)	80,898
Proceeds from warrant and stock option exercises	0	0	898
Principal payments on capital lease obligations	0	0	(331)
Proceeds from issuance of debt, net of issue costs	(2)	9,839	9,837
Principal payments on debt obligations	(2,389)	0	(2,389)
Net cash provided by financing activities	16,060	9,733	88,913
Net increase (decrease) in cash and cash equivalents	4,088	(3,076)	23,259
Cash and cash equivalents - beginning of period	19,171	23,974	0
Cash and cash equivalents - end of period	23,259	20,898	23,259
Cash Paid for Interest	841	528	1,730
Non-Cash Investing Activities:
Capital expenditures acquired on account	0	440	15
Non-Cash Financing Activities:
Accrued financing costs	0	0	167
Series D warrant issuance	$ 4,513	$ 0	$ 4,513