SIGNIFICANT CUSTOMERS AND GEOGRAPHIC NET REVENUES Geograpic Net Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue by Geography
Total net revenues	$ 110,085	$ 111,255	$ 322,648	$ 323,506
United States of America
Revenue by Geography
Total net revenues	4,460	4,775	12,056	13,078
Hong Kong/China
Revenue by Geography
Total net revenues	59,178	59,328	169,149	170,720
Taiwan
Revenue by Geography
Total net revenues	11,210	12,424	36,010	36,220
Korea
Revenue by Geography
Total net revenues	8,087	9,343	25,965	28,527
Western Europe (excluding Germany)
Revenue by Geography
Total net revenues	12,842	12,963	37,910	37,685
Japan
Revenue by Geography
Total net revenues	5,040	4,853	15,238	15,338
Germany
Revenue by Geography
Total net revenues	3,873	2,817	10,882	8,528
Other
Revenue by Geography
Total net revenues	$ 5,395	$ 4,752	$ 15,438	$ 13,410