Commitments and Contingencies - Future Minimum Rental Commitments (Details) $ in Thousands	Jun. 30, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Remaining 2019	$ 84
2020	30
Total cash payments remaining	114
Short-Term Lease
Lessee, Lease, Description [Line Items]
Remaining 2019	40
2020	0
Total cash payments remaining	40
ROU Lease
Lessee, Lease, Description [Line Items]
Remaining 2019	44
2020	30
Total cash payments remaining	$ 74