Goodwill and Other Intangible Assets (Schedule of Identifiable Intangible Assets) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 12,141	$ 13,189
Accumulated Amortization	(5,244)	(5,316)
Intangible Assets, Net	6,897	7,873
Collaboration agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,777	4,103
Accumulated Amortization	(3,188)	(3,310)
Intangible Assets, Net	589	793
Proprietary adjuvant technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	8,364	9,086
Accumulated Amortization	(2,056)	(2,006)
Intangible Assets, Net	$ 6,308	$ 7,080