Restructuring Costs - France - (Details Textual) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 1,164	$ 3,259
Severance costs	776
Curtailment gain	148	717
Lyon France Workforce Reduction \| Employee Severance
Restructuring Cost and Reserve [Line Items]
Percent reduction in workforce			50.00%
Restructuring costs	$ 1,016	$ 2,542

Restructuring And Related Costs, Expected Number Of Positions Eliminated, Percent

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Amount of (increase) decrease in benefit obligation of defined benefit plan from event reducing expected years of future service of present employees or eliminating accrual of benefits for some or all future services of present employees.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.

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