Commitments and Contingencies Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Loss Contingencies [Line Items]
Restructuring expenses	$ 275	$ 90
Restructuring reserve	1,464	315	$ 1,630	$ 492
Employee Severance [Member]
Loss Contingencies [Line Items]
Restructuring expenses	$ 300	$ 100