Property and Equipment Estimated Useful Lives (Details)	12 Months Ended
	Dec. 31, 2012 Y
Machinery and equipment
Property, Plant and Equipment, Useful Life, Minimum	4
Property, Plant and Equipment, Useful Life, Maximum	6
Electronic equipment
Property, Plant and Equipment, Useful Life, Minimum	4
Property, Plant and Equipment, Useful Life, Maximum	6
Transportation equipment
Property, Plant and Equipment, Useful Life, Minimum	4
Property, Plant and Equipment, Useful Life, Maximum	6
Workshop reconstruction
Property, Plant and Equipment, Useful Life, Average	5
Leasehold improvements
Property, Plant and Equipment, Useful Life, Average	5
Computer equipment
Property, Plant and Equipment, Useful Life, Minimum	4
Property, Plant and Equipment, Useful Life, Maximum	6
Office equipment
Property, Plant and Equipment, Useful Life, Minimum	4
Property, Plant and Equipment, Useful Life, Maximum	6