Annual report pursuant to Section 13 and 15(d)

Restructuring Charges - Components of Restructuring Liabilities (Details)

v3.8.0.1
Restructuring Charges - Components of Restructuring Liabilities (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Restructuring Cost And Reserve [Line Items]      
Balance at period start $ 3,594 $ 459  
Restructuring charges 3,447 4,566 $ 3,699
Non-cash charges   (817)  
Cash payments (6,911) (614)  
Balance at period end 130 3,594 459
Employee Severance and Other Benefits [Member]      
Restructuring Cost And Reserve [Line Items]      
Balance at period start 3,594 343  
Restructuring charges 3,447 3,720  
Cash payments (6,911) (469)  
Balance at period end $ 130 3,594 343
Contract Termination Costs [Member]      
Restructuring Cost And Reserve [Line Items]      
Balance at period start   116  
Restructuring charges   29  
Cash payments   (145)  
Balance at period end     $ 116
Stock-based Compensation [Member]      
Restructuring Cost And Reserve [Line Items]      
Restructuring charges   619  
Non-cash charges   (619)  
Asset Impairment [Member]      
Restructuring Cost And Reserve [Line Items]      
Restructuring charges   198  
Non-cash charges   $ (198)