Concentration Risk - Additional Information (Details) (Customer Concentration Risk [Member])
3 Months Ended 12 Months Ended
Mar. 31, 2015
customer
Mar. 31, 2014
customer
Dec. 31, 2014
customer
Sales [Member]
     
Concentration Risk [Line Items]      
Concentration risk, number of customers 1 1  
Concentration risk, percentage, period 35.00% 33.00%  
Accounts Receivable [Member]
     
Concentration Risk [Line Items]      
Concentration risk, number of customers 1   1
Concentration risk, percentage 25.00%   17.00%