Basis of Presentation (Details 2) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Summary of Property and equipment
Property and equipment , Gross	$ 6,215	$ 5,669
Less accumulated depreciation and amortization	(5,457)	(4,881)
Property and equipment, Total	758	788
Lab and office equipment [Member]
Summary of Property and equipment
Property and equipment , Gross	4,837	4,374
Leasehold improvements [Member]
Summary of Property and equipment
Property and equipment , Gross	134	145
Computer equipment and software [Member]
Summary of Property and equipment
Property and equipment , Gross	$ 1,244	$ 1,150

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

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Gross amount of long-lived physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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- Definition

Amount, net of accumulated depreciation, depletion and amortization, of long-lived physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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