SIGNIFICANT CUSTOMERS AND GEOGRAPHIC NET REVENUES Geograpic Net Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue by Geography
Total net revenues	$ 109,482	$ 107,563	$ 212,563	$ 212,251
United States of America
Revenue by Geography
Total net revenues	3,729	4,474	7,596	8,303
Hong Kong/China
Revenue by Geography
Total net revenues	58,614	56,547	109,971	111,392
Taiwan
Revenue by Geography
Total net revenues	12,914	10,762	24,800	23,796
Korea
Revenue by Geography
Total net revenues	8,229	9,678	17,878	19,184
Western Europe (excluding Germany)
Revenue by Geography
Total net revenues	11,476	12,751	25,068	24,722
Japan
Revenue by Geography
Total net revenues	5,647	5,837	10,198	10,485
Germany
Revenue by Geography
Total net revenues	3,705	2,915	7,009	5,711
Other
Revenue by Geography
Total net revenues	$ 5,168	$ 4,599	$ 10,043	$ 8,658