Summary of Significant Accounting Policies - Accounts Receivable and Concentration of Credit Risk (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2014 customer	Jun. 30, 2013 customer	Jun. 30, 2014 customer	Jun. 30, 2013 customer	Dec. 31, 2013 customer
Accounting Policies [Abstract]
Accounts receivable, number of major customers (customers)	2		2		2
Accounts receivable, major customer (percentage)	29.00%		29.00%		23.00%
Revenue, number of major customer (customers)	1	2	1	1
Revenue, major customer (percentage)	12.00%	32.00%	12.00%	12.00%