Work Force Reduction and CEO Transition - Additional Information (Details) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
|
Oct. 18, 2016
position
|
Dec. 31, 2017
USD ($)
|
Dec. 31, 2016
USD ($)
|
|
| Restructuring Reserve [Roll Forward] | |||
| Beginning balance | $ 2,014 | ||
| Severance and benefit related costs | 468 | ||
| Payments | (1,500) | ||
| Adjustments | (46) | ||
| Ending balance | 936 | $ 2,014 | |
| Work Force Reduction | |||
| Restructuring Cost and Reserve [Line Items] | |||
| Number of positions eliminated | position | 62 | ||
| Restructuring Reserve [Roll Forward] | |||
| Severance and benefit related costs | 1,500 | ||
| CEO Transition | |||
| Restructuring Reserve [Roll Forward] | |||
| Severance and benefit related costs | $ 500 | $ 1,200 | |