XML 75 R59.htm IDEA: XBRL DOCUMENT v3.8.0.1
COMMITMENTS AND CONTINGENCIES (Details)
$ in Thousands
 12 Months Ended 36 Months Ended
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Apr. 30, 2020
USD ($)
Dec. 31, 2014
USD ($)
Loss Contingencies [Line Items]          
Restructuring Reserve $ 6,444 $ 10,111 $ 7,180   $ 2,343
Operating Leases, Income Statement, Sublease Revenue 700 600 600    
Rent expense under operating leases, net of operating subleases 11,800 14,100 14,000    
Future minimum lease commitments under non-cancelable leases [Abstract]          
2018 13,942        
2019 11,740        
2020 6,836        
2021 2,927        
2022 2,281        
Thereafter 2,559        
Total $ 40,285        
Purchase Commitments [Abstract]          
Maximum Purchase Commitment Period (in Years) 1 year        
Aggregate total of non-cancelable purchase commitments $ 24,400        
Product warranty accrual [Roll Forward]          
Accrual balance at beginning of year 2,518 2,234 2,792    
Accruals for product warranties 2,572 2,822 3,025    
Cost of warranty claims (2,545) (2,538) (3,583)    
Accrual balance at end of period 2,545 $ 2,518 $ 2,234    
Facilities-Related [Member]          
Loss Contingencies [Line Items]          
Restructuring Reserve 2,500        
Standby Letters of Credit [Member] | Office Space - Burlington, Massachusetts [Member]          
Loss Contingencies [Line Items]          
Letters of Credit Outstanding, Amount 1,300        
Loss Contingency, Range Of Possible Loss, Portion Not Accrued, Minimum $ 1,200        
Number of five-year renewal options on corporate office space in Burlington, Massachusetts 2        
Minimum exposure $ 1,200        
Standby Letters of Credit [Member] | Office Space - Other Facilities [Member]          
Loss Contingencies [Line Items]          
Letters of Credit Outstanding, Amount 1,100        
Standby Letters of Credit [Member] | Other Operating Obligations [Member]          
Loss Contingencies [Line Items]          
Letters of Credit Outstanding, Amount 1,100        
Operating Leases on Vacated Facilities [Member]          
Loss Contingencies [Line Items]          
Effect on Future Cash Flows, Amount 9,100        
Aggregate obligation of vacated facilies $ 9,100        
Scenario, Forecast [Member]          
Loss Contingencies [Line Items]          
Long-term Purchase Commitment, Period       3 years  
Long-term Purchase Commitment, Amount       $ 12,800