Restructuring Expenses (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) Right	Dec. 31, 2016 USD ($)
Restructuring and Related Cost, Expected Cost [Abstract]
Restructuring and Related Cost, Cost Incurred to Date	$ 733
Restructuring and Related Cost, Expected Cost Remaining	956
Restructuring and Related Cost, Expected Cost, Total	1,689
Restructuring Reserve [Roll Forward]
Restructuring Reserve, Beginning Balance	0
Restructuring charges	778	$ 490
Payments for Restructuring	0
Restructuring Reserve, Ending Balance	$ 465	$ 0
Restructuring and Related Cost, Number of Positions Eliminated | Right	40
Employee Severance [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Restructuring and Related Cost, Cost Incurred to Date	$ 465
Restructuring and Related Cost, Expected Cost Remaining	34
Restructuring and Related Cost, Expected Cost, Total	499
Restructuring Reserve [Roll Forward]
Restructuring charges	465
Contract Termination [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Restructuring and Related Cost, Cost Incurred to Date	0
Restructuring and Related Cost, Expected Cost Remaining	665
Restructuring and Related Cost, Expected Cost, Total	665
Assets Write-off [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Restructuring and Related Cost, Cost Incurred to Date	222
Restructuring and Related Cost, Expected Cost Remaining	0
Restructuring and Related Cost, Expected Cost, Total	222
Other Restructuring [Member]
Restructuring and Related Cost, Expected Cost [Abstract]
Restructuring and Related Cost, Cost Incurred to Date	46
Restructuring and Related Cost, Expected Cost Remaining	257
Restructuring and Related Cost, Expected Cost, Total	$ 303