Concentration of Business Risk (Details)	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended			12 Months Ended
	Jun. 30, 2013 Revenue Partner A	Jun. 30, 2012 Revenue Partner A	Jun. 30, 2013 Revenue Partner A	Jun. 30, 2012 Revenue Partner A	Jun. 30, 2013 Revenue Partner B	Jun. 30, 2012 Revenue Partner B	Jun. 30, 2013 Revenue Partner B	Jun. 30, 2012 Revenue Partner B	Jun. 30, 2013 Revenue Partner C	Jun. 30, 2012 Revenue Partner C	Jun. 30, 2013 Revenue Partner C	Jun. 30, 2012 Revenue Partner C	Jun. 30, 2013 Revenue Partner D	Jun. 30, 2012 Revenue Partner D	Jun. 30, 2013 Revenue Partner D	Jun. 30, 2012 Revenue Partner D	Jun. 30, 2013 Contract receivables Significant Partners item	Dec. 31, 2012 Contract receivables Significant Partners item
Concentration of business risk
Concentration percentage	20.00%	90.00%	40.00%	84.00%	6.00%	4.00%	15.00%	6.00%	40.00%	0.00%	22.00%	0.00%	19.00%	4.00%	14.00%	5.00%	89.00%	83.00%
Number of significant partners																	4	4