SIGNIFICANT CUSTOMERS AND GEOGRAPHIC NET REVENUES Geograpic Net Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue by Geography
Total net revenues	$ 103,081	$ 104,688
United States of America
Revenue by Geography
Total net revenues	3,867	3,829
Hong Kong/China
Revenue by Geography
Total net revenues	51,357	54,845
Taiwan
Revenue by Geography
Total net revenues	11,886	13,034
Korea
Revenue by Geography
Total net revenues	9,649	9,506
Western Europe (excluding Germany)
Revenue by Geography
Total net revenues	13,592	11,971
Japan
Revenue by Geography
Total net revenues	4,551	4,648
Germany
Revenue by Geography
Total net revenues	3,304	2,796
Other
Revenue by Geography
Total net revenues	$ 4,875	$ 4,059