Goodwill and Other Intangible Assets - Schedule of Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 11,675	$ 12,130
Accumulated Amortization	(5,717)	(5,589)
Intangible Assets, Net	5,958	6,541
Proprietary adjuvant technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	8,043	8,357
Accumulated Amortization	(2,379)	(2,263)
Intangible Assets, Net	5,664	6,094
Collaboration agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,632	3,773
Accumulated Amortization	(3,338)	(3,326)
Intangible Assets, Net	$ 294	$ 447