Summary of Significant Accounting Policies (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash (in Dollars)	$ 6,878,000	$ 3,471,000	$ 5,007,000
Allowance for Doubtful Accounts Receivable (in Dollars)	400,000	300,000
Inventory Write-down (in Dollars)	1,279,000	96,000
Depreciation (in Dollars)	700,000	800,000
Amortization of Intangible Assets (in Dollars)	700,000	900,000
Financial Instruments, Owned, at Fair Value (in Dollars)	7,500,000
Machinery and Equipment [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life	2 years
Machinery and Equipment [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life	10 years
Vehicles [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life	2 years
Vehicles [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life	5 years
Furniture and Fixtures [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life	2 years
Furniture and Fixtures [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life	5 years
Computer Hardware And Software [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life	2 years
Computer Hardware And Software [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life	5 years
Precious Metals [Member]
Inventory, Raw Materials, Gross (in Dollars)	$ 800,000	$ 600,000
Minimum [Member]
Finite-Lived Intangible Asset, Useful Life	4 years
Maximum [Member]
Finite-Lived Intangible Asset, Useful Life	20 years