Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Development revenue	$ 1,691us-gaap_OtherSalesRevenueNet	$ 2,909us-gaap_OtherSalesRevenueNet
Product revenue	392us-gaap_SalesRevenueGoodsNet	2,341us-gaap_SalesRevenueGoodsNet
Contract revenue	1,402us-gaap_ContractsRevenue	602us-gaap_ContractsRevenue
Total revenue	3,485us-gaap_Revenues	5,852us-gaap_Revenues
Cost of product revenue	228us-gaap_CostOfGoodsSold	1,518us-gaap_CostOfGoodsSold
Cost of contract revenue	816us-gaap_ContractRevenueCost	283us-gaap_ContractRevenueCost
Total cost of revenue	1,044us-gaap_CostOfRevenue	1,801us-gaap_CostOfRevenue
Gross margin	2,441us-gaap_GrossProfit	4,051us-gaap_GrossProfit
Research and development expense	9,067us-gaap_ResearchAndDevelopmentExpense	10,544us-gaap_ResearchAndDevelopmentExpense
Sales, marketing, general and administrative expense	7,005	8,757
Gain on sale of previously reserved inventory	(463)us-gaap_GainLossOnSaleOfOtherAssets	(156)us-gaap_GainLossOnSaleOfOtherAssets
Total operating expenses	15,609us-gaap_OperatingExpenses	19,145us-gaap_OperatingExpenses
Loss from operations	(13,168)us-gaap_OperatingIncomeLoss	(15,094)us-gaap_OperatingIncomeLoss
Gain (loss) on warrant exchange	(4,967)	1,900
Other income (expense)	15us-gaap_OtherNonoperatingIncomeExpense	16us-gaap_OtherNonoperatingIncomeExpense
Net loss	$ (18,120)us-gaap_NetIncomeLoss	$ (13,178)us-gaap_NetIncomeLoss
Net loss per share - basic and diluted	$ (0.44)us-gaap_EarningsPerShareBasicAndDiluted	$ (0.47)us-gaap_EarningsPerShareBasicAndDiluted
Weighted-average shares outstanding - basic and diluted	41,599	28,025

Costs incurred and are directly related to generating contract revenues.

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