Fair Value Measurements - Narrative (Details) $ in Thousands |
Sep. 30, 2017
USD ($)
ft²
|
Dec. 31, 2016
USD ($)
|
Apr. 14, 2016
ft²
|
|---|---|---|---|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | |||
| Restructuring accrual | $ | $ 3,818 | $ 356 | |
| Massachusetts | |||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | |||
| Area of real estate property | ft² | 108,743 | ||
| Massachusetts | Property Subject to Operating Lease | |||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | |||
| Area of real estate property | ft² | 25,812 | 10,362 | |
| Restructuring accrual | $ | $ 3,527 |