Concentration of Risk (Details) - item	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Revenue | Customer concentration risk
Concentration of risk
Number of customers	3	1
Revenue | Customer concentration risk | One customer
Concentration of risk
Percentage of concentration risk	20.80%	36.50%
Revenue | Customer concentration risk | Second customer
Concentration of risk
Percentage of concentration risk	13.40%
Revenue | Customer concentration risk | Third customer
Concentration of risk
Percentage of concentration risk	13.20%
Consolidated accounts receivable | Credit concentration risk
Concentration of risk
Number of customers	2		3
Consolidated accounts receivable | Credit concentration risk | One customer
Concentration of risk
Percentage of concentration risk	20.40%		22.90%
Consolidated accounts receivable | Credit concentration risk | Second customer
Concentration of risk
Percentage of concentration risk	10.30%		12.70%
Consolidated accounts receivable | Credit concentration risk | Third customer
Concentration of risk
Percentage of concentration risk			11.60%