Commitments and Contingencies - Concentrations of credit risk (Detail Textuals 3) (Concentrations of credit risk)	12 Months Ended
	Dec. 31, 2012 Customer	Dec. 31, 2011 Customer
Accounts Receivable
Concentration Risk [Line Items]
Number of customers	4	5
Percentage of concentration risk	82.20%	83.00%
Accounts Receivable | Customer One
Concentration Risk [Line Items]
Percentage of concentration risk	63.10%	27.00%
Accounts Receivable | Customer Two
Concentration Risk [Line Items]
Percentage of concentration risk	7.70%	17.30%
Accounts Receivable | Customer Three
Concentration Risk [Line Items]
Percentage of concentration risk	6.30%	16.40%
Accounts Receivable | Customer Four
Concentration Risk [Line Items]
Percentage of concentration risk	5.10%	12.10%
Accounts Receivable | Customer Five
Concentration Risk [Line Items]
Percentage of concentration risk		10.20%
Revenues
Concentration Risk [Line Items]
Number of customers	2	3
Percentage of concentration risk	43.10%	39.00%
Revenues | Customer One
Concentration Risk [Line Items]
Percentage of concentration risk	27.70%	14.50%
Revenues | Customer Two
Concentration Risk [Line Items]
Percentage of concentration risk	15.40%	14.00%
Revenues | Customer Three
Concentration Risk [Line Items]
Percentage of concentration risk		10.50%