Income Taxes - Tax Provision (Details) - USD ($) $ in Thousands |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Current | ||
| State | $ (6) | $ 25 |
| Foreign | 34 | 139 |
| Current tax expense | 28 | 164 |
| Deferred | ||
| Federal | (7) | |
| Foreign | 24 | (14) |
| Deferred tax expense | 24 | (21) |
| Total income tax expense | $ 52 | $ 143 |