Property And Equipment (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Gross property and equipment	$ 9,888,037	$ 11,420,800
Less: Accumulated depreciation	(9,295,349)	(10,334,556)
Net property and equipment	592,688	1,086,244
Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross property and equipment	7,295,698	8,397,528
Equipment Held For Lease [Member]
Property, Plant and Equipment [Line Items]
Gross property and equipment		303,412
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Gross property and equipment	$ 2,592,339	$ 2,719,860