Goodwill and Other Intangible Assets (Schedule of Identifiable Intangible Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 13,004	$ 13,189
Accumulated Amortization	(5,429)	(5,316)
Intangible Assets, Net	7,575	7,873
Collaboration agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	4,045	4,103
Accumulated Amortization	(3,339)	(3,310)
Intangible Assets, Net	706	793
Proprietary adjuvant technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	8,959	9,086
Accumulated Amortization	(2,090)	(2,006)
Intangible Assets, Net	$ 6,869	$ 7,080