Property and equipment (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Property And Equipment Details
Production equipment	$ 5,201,000	$ 5,144,000
Leasehold improvements	3,344,000	3,344,000
Computer hardware and software/lab equipment	9,002,000	8,917,000
Office furniture and equipment	1,485,000	1,485,000
Property and equipment, gross	19,032,000	18,890,000
Less: Accumulated depreciation	(17,827,000)	(16,543,000)
Property and equipment, net	$ 1,205,000	$ 2,347,000

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, at the balance sheet date, of long-lived physical assets used in the normal conduct of business and not intended for resale. This can include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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- Definition

Tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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