CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Revenues:
Research grant and other	$ 194us-gaap_RevenueFromGrants	$ 0us-gaap_RevenueFromGrants
Total revenues	194us-gaap_SalesRevenueNet	0us-gaap_SalesRevenueNet
Operating costs and expenses:
Research and development	19,703us-gaap_ResearchAndDevelopmentExpense	19,986us-gaap_ResearchAndDevelopmentExpense
General and administrative	3,319us-gaap_GeneralAndAdministrativeExpense	3,693us-gaap_GeneralAndAdministrativeExpense
Depreciation and amortization	3us-gaap_DepreciationAndAmortization	3us-gaap_DepreciationAndAmortization
Total operating costs and expenses	23,025us-gaap_OperatingCostsAndExpenses	23,682us-gaap_OperatingCostsAndExpenses
Loss from operations	(22,831)us-gaap_OperatingIncomeLoss	(23,682)us-gaap_OperatingIncomeLoss
Other income (expense):
Inducement expense	0	(5,251)
Change in fair value of derivative liability	(23,158)	(16,984)
Interest expense	(793)us-gaap_InterestExpense	(122)us-gaap_InterestExpense
Gain (loss) on foreign currency exchange	349	(2)
Net loss	$ (46,433)us-gaap_NetIncomeLoss	$ (46,041)us-gaap_NetIncomeLoss
Net loss per share applicable to common stockholders - basic and diluted (in dollars per share)	$ (0.67)us-gaap_EarningsPerShareBasicAndDiluted	$ (0.88)us-gaap_EarningsPerShareBasicAndDiluted
Weighted average shares used in computing basic and diluted loss per share (in shares)	69,406	52,377

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Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

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