Defined Benefit Plans (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Swiss Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 149	$ 150	$ 308	$ 305
Additional employer contributions expected to be paid during the remainder of fiscal year	247		247
Korea Defined Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	2	$ 1	4	$ 1
Additional employer contributions expected to be paid during the remainder of fiscal year	$ 3		$ 3
Minimum years of service			1 year