INCOME TAXES - Valuation Allowance(Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Valuation Allowance [Line Items]
Valuation allowance	$ 12,375	$ 12,793
AUSTRALIA
Valuation Allowance [Line Items]
Valuation allowance	200	300
CHINA
Valuation Allowance [Line Items]
Valuation allowance	300	300
China
Valuation Allowance [Line Items]
Valuation allowance	600	600
Hong Kong
Valuation Allowance [Line Items]
Valuation allowance	0	100
Mexico
Valuation Allowance [Line Items]
Valuation allowance	3,300	3,100
Norway
Valuation Allowance [Line Items]
Valuation allowance	100	100
Norway
Valuation Allowance [Line Items]
Valuation allowance	200	200
Sweden
Valuation Allowance [Line Items]
Valuation allowance	0	100
Switzerland(3)
Valuation Allowance [Line Items]
Valuation allowance	500	0
Taiwan
Valuation Allowance [Line Items]
Valuation allowance	1,000	900
Taiwan
Valuation Allowance [Line Items]
Valuation allowance	100	100
United States - Federal
Valuation Allowance [Line Items]
Valuation allowance	100	100
United Kingdom
Valuation Allowance [Line Items]
Valuation allowance	6,000	6,900
United States
Valuation Allowance [Line Items]
Valuation allowance	$ 0	$ 0