Deferred Revenue (Schedule Of Deferred Revenue) (Details) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Deferred Revenue Arrangement [Line Items]
Deferred revenue	$ 10,303,213	$ 9,980,098
Less: Long-term deferred revenue	(359,606)	(477,159)
Total current deferred revenue	9,943,607	9,502,939
Product Shipped, Revenue Deferred [Member]
Deferred Revenue Arrangement [Line Items]
Deferred revenue	3,510,417	3,206,641
Customer Deposits [Member]
Deferred Revenue Arrangement [Line Items]
Deferred revenue	466,904	558,227
Deferred Service And License Fees [Member]
Deferred Revenue Arrangement [Line Items]
Deferred revenue	$ 6,325,892	$ 6,215,230