Balance Sheet Information (Details Textual) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Balance Sheet Information (Textual) [Abstract]
Allowance for doubtful accounts	$ 200,000		$ 200,000
Consigned inventory with customers	1,500,000		1,200,000
Allowance for inventory losses	2,000,000		2,000,000
Depreciation and amortization expense	$ 700,000	$ 600,000
Maximum [Member]
Property, Plant and Equipment [Line Items]
Standard term of accounts receivable	60 days
Useful lives of the assets	1 year
Minimum [Member]
Property, Plant and Equipment [Line Items]
Standard term of accounts receivable	30 days
Building [Member]
Property, Plant and Equipment [Line Items]
Useful lives of the assets	30 years
Manufacturing and test equipment [Member]
Property, Plant and Equipment [Line Items]
Period over which assets are deprecated	5 years
Motor Vehicles [Member]
Property, Plant and Equipment [Line Items]
Period over which assets are deprecated	5 years
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Period over which assets are deprecated	7 years
Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Period over which assets are deprecated	5 years
Computer Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Period over which assets are deprecated	5 years
Computer Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Period over which assets are deprecated	3 years