Description of Business and Basis of Presentation (Details Textual) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Segment manufacturing_location	Sep. 30, 2012	Dec. 31, 2012
Description of Business and Basis of Presentation [Line Items]
Deferred Revenue, Additions	$ 3,900,000	$ 4,000,000	$ 13,400,000	$ 16,900,000
Deferred Revenue, Revenue Recognized	15,200,000	1,200,000	24,900,000	6,600,000
Inventory, Finished Goods, Consigned	3,206,000		3,206,000		9,242,000
Description of Business and Basis of Presentation (Textual) [Abstract]
Manufacturing locations			2
Operating segments			1
Restricted cash	4,050,000		4,050,000		0
Warranty period, minimum, in years			1 year
Warranty period, maximum, in years			2 years
Standby Letters of Credit [Member]
Description of Business and Basis of Presentation (Textual) [Abstract]
Restricted cash	2,300,000		2,300,000
Collateral for Borrowing [Member]
Description of Business and Basis of Presentation (Textual) [Abstract]
Restricted cash	$ 1,800,000		$ 1,800,000