Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal	$ 0	$ 0	$ 0
State	0	0	0
Foreign	267	0	0
Total current provision	267	0	0
Deferred:
Federal	0	0	0
State	0	0	0
Foreign	0	0	0
Total deferred provision	0	0	0
Total provision	$ 267	$ 0	$ 0