Restructuring (Details) $ in Thousands	1 Months Ended	3 Months Ended
	May 31, 2017 employee	Dec. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve		$ 1,631		$ 1,656
Q3 2017 Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			$ 2,500
Restructuring Reserve		1,631		1,656
Payments		(48)
Foreign currency fluctuation		23
Employee Termination Costs | Q3 2017 Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			2,300
Restructuring Reserve		1,555		1,528
Payments		5
Foreign currency fluctuation		22
Other | Q3 2017 Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			$ 200
Restructuring Reserve		76		$ 128
Payments		(53)
Foreign currency fluctuation		$ 1
UNITED STATES | Q3 2017 Restructuring
Restructuring Cost and Reserve [Line Items]
Number of employees eliminated | employee	10
FRANCE | Q3 2017 Restructuring
Restructuring Cost and Reserve [Line Items]
Number of employees eliminated | employee	8