Research Grants And Agreements (Narrative) (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2017
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and development expense	$ 6,337,000	$ 3,960,000	$ 12,179,000	$ 7,136,000
Sponsored Research Agreement ("SRA") [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and development expense	300,000	100,000	500,000	$ 400,000
Remaining sponsorship	100,000		$ 100,000
ODURF [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Period of time for Sponsored Research Agreement ("SRA")			12 months
ODURF [Member] | Sponsored Research Agreement ("SRA") [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and development expense		$ 800,000
ODURF And Eastern Virginia Medical School [Member] | Sponsored Research Agreement ("SRA") [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and development expense					$ 300,000
Remaining sponsorship	$ 0		$ 0