Commitments and Contingencies - Future Minimum Annual Lease Payments (Details) $ in Thousands	Sep. 30, 2018 USD ($)
Commitments And Contingencies Disclosure [Abstract]
Operating leases Remainder of 2018	$ 411
Operating leases 2019	1,665
Operating leases 2020	1,688
Operating leases 2021	1,009
Total Operating leases	4,773
Capital leases Remainder of 2018	9
Capital leases 2019	37
Capital leases 2020	37
Capital leases 2021	37
Capital leases 2022 and thereafter	37
Total Capital leases	157
Less: amount representing interest	(22)
Present value of minimum lease payments	135
Current portion of capital leases	(7)
Capital leases, less current portion	$ 128