Fixed Assets (Fixed Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Fixed assets, gross	$ 17,943	$ 19,347
Less accumulated depreciation and amortization	(13,651)	(13,920)
Fixed assets, net	4,292	5,427
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Fixed assets, gross	10,120	10,274
Office Equipment and Furniture [Member]
Property, Plant and Equipment [Line Items]
Fixed assets, gross	1,488	2,193
Machinery and Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Fixed assets, gross	2,765	3,255
Software [Member]
Property, Plant and Equipment [Line Items]
Fixed assets, gross	3,162	3,581
Construction-in-progress [Member]
Property, Plant and Equipment [Line Items]
Fixed assets, gross	$ 408	$ 44
Minimum [Member] | Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Useful Life (Years)	4 years
Minimum [Member] | Office Equipment and Furniture [Member]
Property, Plant and Equipment [Line Items]
Useful Life (Years)	3 years
Minimum [Member] | Machinery and Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Useful Life (Years)	3 years
Minimum [Member] | Software [Member]
Property, Plant and Equipment [Line Items]
Useful Life (Years)	1 year
Maximum [Member] | Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Useful Life (Years)	8 years
Maximum [Member] | Office Equipment and Furniture [Member]
Property, Plant and Equipment [Line Items]
Useful Life (Years)	15 years
Maximum [Member] | Machinery and Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Useful Life (Years)	15 years
Maximum [Member] | Software [Member]
Property, Plant and Equipment [Line Items]
Useful Life (Years)	5 years