Income Taxes Components of income tax expense/ (benefit) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Federal:
Current									$ 0	$ 0	$ 0
Deferred									0	0	0
Total federal provision									0	0	0
State:
Current									16	17	5
Deferred									0	0	0
Total state provision									16	17	5
Foreign:
Current									195	294	214
Deferred									0	0	0
Total foreign provision									195	294	214
Total income tax expense	$ 97	$ 33	$ 106	$ (25)	$ 55	$ 113	$ 106	$ 37	$ 211	$ 311	$ 219