Reduction in Workforce (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Restructuring and Related Activities [Abstract]
Expected cost		$ 100
Severance costs paid	$ 100
Restructuring Reserve
Balance as of January 1, 2017	111
Payments	(53)
Balance as of March 31, 2018	$ 58