Concentrations of Credit and Other Risks (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration of share of accounts receivable, maximum (in hundredths)	10.00%		10.00%		10.00%
Concentration of revenue share, maximum (in hundredths)	10.00%	10.00%	10.00%	10.00%
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk, percentage (in hundredths)			85.00%	84.00%
International Markets [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk, percentage (in hundredths)			15.00%	16.00%