Concentration of Business Risk (Details)	3 Months Ended	12 Months Ended
Mar. 31, 2013 Revenue Partner A	Mar. 31, 2012 Revenue Partner A	Mar. 31, 2013 Revenue Partner B	Mar. 31, 2012 Revenue Partner B	Mar. 31, 2013 Contract receivables Significant Partners item	Dec. 31, 2012 Contract receivables Significant Partners item
Concentration of business risk
Concentration percentage	58.00%	71.00%	23.00%	9.00%	88.00%	83.00%
Number of significant partners					4	4

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 18

-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

-Topic 825

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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-URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13531-108611

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