Commitments and Contingencies - Operating Leases (Details) $ in Thousands |
12 Months Ended | |
|---|---|---|
|
Dec. 31, 2017
USD ($)
item
|
Dec. 31, 2016
USD ($)
|
|
| Commitments and Contingencies Disclosure [Abstract] | ||
| Tenant improvement allowance | $ 1,300 | |
| Operating lease abatement period | 1 year | |
| Operating leases, future minimum payments due | ||
| 2018 | $ 1,796 | |
| 2019 | 1,718 | |
| 2020 | 1,473 | |
| 2021 | 1,024 | |
| 2022 | 952 | |
| Thereafter | 1,990 | |
| Total future minimum rental payments | 8,953 | |
| Rent expense under operating leases | 1,500 | $ 1,500 |
| Accrued lease impairment charges | 300 | |
| Subleasing payments received | $ 500 | |
| Sublease Agreements, number of facilities | item | 2 | |
| Future Minimum Sublease Rentals, Fiscal Year Maturity [Abstract] | ||
| 2018 | $ 342 | |
| 2019 | 328 | |
| 2020 | 335 | |
| 2021 | 28 | |
| Subleases, Future Receipts, Total | $ 1,033 | |