Goodwill and Other Intangible Assets (Schedule of Identifiable Intangible Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 12,130	$ 13,189
Accumulated Amortization	(5,589)	(5,316)
Intangible Assets, Net	6,541	7,873
Collaboration agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,773	4,103
Accumulated Amortization	(3,326)	(3,310)
Intangible Assets, Net	447	793
Proprietary adjuvant technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	8,357	9,086
Accumulated Amortization	(2,263)	(2,006)
Intangible Assets, Net	$ 6,094	$ 7,080