SIGNIFICANT CUSTOMERS AND GEOGRAPHIC NET REVENUES Geographic Net Revevnues (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of Revenues by Geography [Line Items]
Revenues	$ 114,457	$ 114,159	$ 102,865	$ 89,188	$ 93,307	$ 110,085	$ 109,482	$ 103,081	$ 420,669	$ 415,955	$ 431,755
United States of America
Schedule of Revenues by Geography [Line Items]
Revenues									10,662	15,315	16,647
Hong Kong/China
Schedule of Revenues by Geography [Line Items]
Revenues									237,341	218,752	227,335
Taiwan
Schedule of Revenues by Geography [Line Items]
Revenues									36,297	43,081	50,307
Korea
Schedule of Revenues by Geography [Line Items]
Revenues									30,395	33,877	38,012
Western Europe (excluding Germany)
Schedule of Revenues by Geography [Line Items]
Revenues									36,025	49,834	48,230
Japan
Schedule of Revenues by Geography [Line Items]
Revenues									15,496	19,897	20,769
Germany
Schedule of Revenues by Geography [Line Items]
Revenues									20,197	14,403	11,558
Other
Schedule of Revenues by Geography [Line Items]
Revenues									$ 34,256	$ 20,796	$ 18,897