The Merger - Consolidated statement of operations (Details) - USD ($)		3 Months Ended		6 Months Ended
	May 09, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Business Acquisition [Line Items]
General and administrative expenses		$ 2,082,000	$ 557,000	$ 3,462,000	$ 1,196,000
Net loss		(4,199,000)	(3,167,000)	(7,938,000)	(12,830,000)
AmpliPhi Biosciences Corporation [Member]
Business Acquisition [Line Items]
Incurred and expensed costs	$ 1,100,000	500,000		1,100,000
Research and development expenses		749,000
General and administrative expenses		730,000
Net loss		(1,475,000)
Business Acquisition, Pro Forma Information [Abstract]
Net loss		$ (5,976,000)	$ (5,885,000)	$ (13,413,000)	$ (18,354,000)