Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (a)
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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Liquidity (Narrative) (Details) - USD ($)	12 Months Ended
Liquidity (Narrative) (Details) - USD ($)	Dec. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash and cash equivalents	$ 9,663,000	$ 8,690,000	$ 13,393,000
AmpliPhi Biosciences Corporation [Member]
Cash and cash equivalents	$ 8,157,000			$ 5,132,000	$ 5,711,000
Liquidity, management evaluation	Considering the Company's current cash resources, management believes the Company's existing resources, without considering any effect of the pending merger with C3J and related financing, will be sufficient to fund the Company's planned operations into mid-2019.
C3J [Member]
Cash and cash equivalents	$ 9,663,000			$ 11,376,000