Quarterly report pursuant to Section 13 or 15(d)

Restructuring Charges - Components of Accrued Restructuring Costs (Details)

v3.8.0.1
Restructuring Charges - Components of Accrued Restructuring Costs (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Dec. 31, 2017
Restructuring Cost And Reserve [Line Items]      
Balance at period start $ 130    
Restructuring charges   $ 2,020  
Balance at period end     $ 130
Employee Severance and Other Benefits [Member]      
Restructuring Cost And Reserve [Line Items]      
Balance at period start 130 $ 3,594 3,594
Restructuring charges     3,447
Cash payments $ (130)   (6,911)
Balance at period end     $ 130