Deferred Revenue (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred Revenue Arrangement [Line Items]
Total deferred revenue, current portion	$ 15,540	$ 1,563
Total deferred revenue, net of current portion	3,656	4,585
Customer prepayments [Member]
Deferred Revenue Arrangement [Line Items]
Total deferred revenue, current portion	3,505	1,563
Total deferred revenue, net of current portion	3,656	4,585
Minimum commitment fees [Member]
Deferred Revenue Arrangement [Line Items]
Total deferred revenue, current portion	$ 12,035	$ 0