Deferred Warranty Revenue and Warranty Reserve (Details Textual)	12 Months Ended
	Dec. 31, 2012
Minimum [Member]
Deferred Warranty Revenue and Warranty Reserve (Textual) (Abstract)
Warranty for hardware purchase	1 year
Purchase extended warranties covering periods	1 year
Maximum [Member]
Deferred Warranty Revenue and Warranty Reserve (Textual) (Abstract)
Warranty for hardware purchase	2 years
Purchase extended warranties covering periods	4 years