Income Taxes Components of income tax expense/ (benefit) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Federal:
Current									$ 0	$ 0	$ 0
Deferred									0	0	0
Total federal provision									0	0	0
State:
Current									18	20	16
Deferred									0	0	0
Total state provision									18	20	16
Foreign:
Current									164	30	195
Deferred									0	0	0
Total foreign provision									164	30	195
Total income tax expense	$ 102	$ 23	$ 51	$ 6	$ (14)	$ (10)	$ 61	$ 13	$ 182	$ 50	$ 211