INCOME TAXES - Valuation Allowance(Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Valuation Allowance [Line Items]
Valuation allowance	$ 11,436	$ 8,458
Colombia
Valuation Allowance [Line Items]
Valuation allowance	600	300
Mexico
Valuation Allowance [Line Items]
Valuation allowance	2,800	2,400
South Africa
Valuation Allowance [Line Items]
Valuation allowance	100	0
Sweden
Valuation Allowance [Line Items]
Valuation allowance	100	100
Switzerland
Valuation Allowance [Line Items]
Valuation allowance	0	100
Taiwan
Valuation Allowance [Line Items]
Valuation allowance	800	1,300
Ukraine
Valuation Allowance [Line Items]
Valuation allowance	100	100
United Kingdom
Valuation Allowance [Line Items]
Valuation allowance	100	0
United States
Valuation Allowance [Line Items]
Valuation allowance	6,800	4,100
Other Jurisdictions
Valuation Allowance [Line Items]
Valuation allowance	$ 0	$ 100