Inventories and Deferred Costs of Goods Sold (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Raw materials	$ 1,616		$ 1,784
Work in process	2,080		2,103
Finished goods	1,466		1,429
Net inventory	5,162		5,316
Deferred cost of goods sold	131		185
Inventory Valuation Reserves	1,000		860
Inventory write-off	$ 0	$ 29