Commitments and Contingencies (Schedule of Annual Minimum Operating Lease Payments) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Operating Lease, Liability	$ 3,837	$ 4,200	$ 0
Remainder of 2019	321
Operating Leases, Future Minimum Payments, Due in Two Years	1,320
Lessee, Operating Lease, Liability, Payments, Due Year Three	1,096
2021	819
Lessee, Operating Lease, Liability, Payments, Due Year Five	622
Total future lease payments	$ 4,178