v3.8.0.1
SIGNIFICANT ACCOUNTING POLICIES - Revenue Recognition (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Sales Revenue, Net | Customer One | Customer Concentration Risk      
Concentration Risk [Line Items]      
Concentration risk percentage 10.10% 10.70% 10.40%
Sales Revenue, Net | Customer Two | Customer Concentration Risk      
Concentration Risk [Line Items]      
Concentration risk percentage 10.10% 10.10%  
International      
Concentration Risk [Line Items]      
Deferred revenue $ 1,654 $ 1,660  
Inventories, net $ 1,047 $ 924