Restructuring and Exit Costs (Details Textual) ft² in Thousands, $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended	13 Months Ended
	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2016 USD ($)	Jun. 30, 2015 ft²
Restructuring Cost and Reserve [Line Items]
Restructuring and exit costs	$ 47		$ (1,251)	$ 26	$ (2,248)
Lease Obligation Costs
Restructuring Cost and Reserve [Line Items]
Restructuring and exit costs		$ 100	$ (200)
Amount of liability	500			500		$ 700	$ 500
September 2017 Restructuring Plan | Restructuring and exit costs
Restructuring Cost and Reserve [Line Items]
Restructuring and exit costs				(112)			(1,100)
September 2017 Restructuring Plan | Employee Severance Costs
Restructuring Cost and Reserve [Line Items]
Restructuring and exit costs				(45)		(1,275)
Reversals of expense				157		27
Cash payments with restructuring plan				705		431
Amount of liability	0			0		817	0	$ 0
February 2017 Restructuring Plan | Restructuring and exit costs
Restructuring Cost and Reserve [Line Items]
Restructuring and exit costs						(900)
February 2017 Restructuring Plan | Employee Severance Costs
Restructuring Cost and Reserve [Line Items]
Restructuring and exit costs				0		(997)
Reversals of expense				0		142
Cash payments with restructuring plan				0		855
Amount of liability	$ 0			$ 0		$ 0	$ 0	$ 0
2015 Consolidation of US Manufacturing Operations | Lease Obligation Costs
Restructuring Cost and Reserve [Line Items]
Square feet of manufacturing facility | ft²									60