Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Revenue:
Product and service	$ 10,832us-gaap_SalesRevenueNet	$ 8,751us-gaap_SalesRevenueNet
Collaboration	761us-gaap_RecognitionOfDeferredRevenue	0us-gaap_RecognitionOfDeferredRevenue
Total revenue	11,593us-gaap_Revenues	8,751us-gaap_Revenues
Costs and expenses:
Cost of product and service revenue	5,340us-gaap_CostOfRevenue	4,325us-gaap_CostOfRevenue
Research and development	5,916us-gaap_ResearchAndDevelopmentExpense	4,732us-gaap_ResearchAndDevelopmentExpense
Selling, general and administrative	14,125	10,674
Total costs and expenses	25,381us-gaap_CostsAndExpenses	19,731us-gaap_CostsAndExpenses
Loss from operations	(13,788)us-gaap_OperatingIncomeLoss	(10,980)us-gaap_OperatingIncomeLoss
Other income (expense):
Interest income	67us-gaap_InvestmentIncomeInterest	64us-gaap_InvestmentIncomeInterest
Interest expense	(984)	(536)
Other income (expense)	(189)us-gaap_OtherNonoperatingIncomeExpense	30us-gaap_OtherNonoperatingIncomeExpense
Total other income (expense), net	(1,106)us-gaap_NonoperatingIncomeExpense	(442)us-gaap_NonoperatingIncomeExpense
Net loss	$ (14,894)us-gaap_NetIncomeLoss	$ (11,422)us-gaap_NetIncomeLoss
Net loss per share - basic and diluted	$ (0.81)us-gaap_EarningsPerShareBasicAndDiluted	$ (0.68)us-gaap_EarningsPerShareBasicAndDiluted
Weighted average shares used in computing basic and diluted net loss per share	18,310	16,917

The aggregate cost of goods produced and sold and services rendered during the reporting period.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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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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The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc.

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Average number of shares or units issued and outstanding that are used in calculating basic and diluted earnings per share (EPS).

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