PROVISION FOR INCOME TAXES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net				$ (189)
U.S. and foreign components of income before income taxes [Abstract]
U.S. operations	$ (6,944)		$ (477)	(2,246)
Foreign operations	67,243		50,429	41,577
INCOME BEFORE INCOME TAXES	60,299		49,952	39,331
Current provision:
Federal	35,311		0	443
State	4		0	83
Foreign	1,483		1,638	5,407
Current provision	36,798		1,638	5,933
Deferred provision (benefit):
Federal	(3,640)		(175)	(1,791)
State	0		(27)	(57)
Foreign	(468)		(382)	(3,906)
Deferred provision (benefit)	(4,108)		(584)	(5,754)
Total	$ 32,690		$ 1,054	$ 179
Effective income tax rate reconciliation [Abstract]
Provision computed at Federal statutory rate	35.00%		35.00%	35.00%
Business tax credits	(5.70%)		(6.00%)	(6.80%)
Stock-based compensation	(5.00%)		2.20%	0.80%
Foreign income taxed at different rate	(37.30%)		(33.10%)	(33.20%)
IRS audit settlement	54.10%		0.00%	0.00%
U.S. Tax Act - deferred tax asset and liability adjustment	8.10%		0.00%	0.00%
Valuation allowance	2.20%		1.80%	2.60%
Other	2.80%		2.20%	2.10%
Total	54.20%		2.10%	0.50%
Components of deferred income tax asset [Abstract]
Other reserves and accruals	$ 979		$ 1,267
Tax credit carry-forwards	10,442		26,895
Stock compensation	4,064		5,760
Capital losses	163		10,585
Net operating loss	7,059		2,671
Deferred Tax Assets, Other	0		174
Valuation allowance	(18,421)		(27,489)
Deferred tax assets, net of valuation allowance	4,286		19,863
Depreciation	(1,965)		(2,322)
Unremitted earnings	0		(7,019)
Other	(95)		0
Deferred tax liabilities	(2,060)		(9,341)
Net deferred tax asset	2,226	[1]	10,522
Reconciliation of the Beginning and Ending Amount of Unrecognized Tax Benefits [Roll Forward]
Unrecognized Tax Benefits, Balance at beginning of period	15,393		13,560	$ 11,160
Gross Increase for Tax Positions of Current Year	1,699		1,856	3,063
Gross Decrease for Tax Positions of Prior Years	(409)		(23)	(663)
Unrecognized Tax Benefits, Balance at end of period	16,683		15,393	13,560
Unrecognized tax benefits [Abstract]
Unrecognized Tax Benefits, Balance at end of period	16,683		15,393	$ 13,560
Income tax benefit that would be recorded if unrecognized tax benefits are recognized	10,300
Income tax interest and penalties accrued	100		$ 100
U.S. Tax Cuts and Jobs Act [Abstract]
Provisional One-Time Transition Tax Related to Tax Cuts and Jobs Act	$ 35,300
Future Effective Federal Income Tax Rate Percent	21.00%
Provisional Net Adjustment of Deferred Tax Assets and Liabilities Related to Tax Cuts and Jobs Act	$ 4,900
Current Federal Tax Expense Related to Impact of Tax Cuts and Jobs Act	37,500
State and Local Jurisdiction [Member] | California Taxing Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	46,600
Research Tax Credit Carryforward [Member] | State and Local Jurisdiction [Member] | California Taxing Authority [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforward, amount	21,500
Research Tax Credit Carryforward [Member] | State and Local Jurisdiction [Member] | New Jersey Division of Taxation [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforward, amount	800
Research Tax Credit Carryforward [Member] | Foreign Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforward, amount	$ 2,400
Earliest Tax Year [Member] | State and Local Jurisdiction [Member] | California Taxing Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, Expiration Date	Jan. 01, 2032
Earliest Tax Year [Member] | Research Tax Credit Carryforward [Member] | State and Local Jurisdiction [Member] | New Jersey Division of Taxation [Member]
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards, Expiration Date	Jan. 01, 2026
Earliest Tax Year [Member] | Research Tax Credit Carryforward [Member] | Foreign Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforwards, Expiration Date	Jan. 01, 2030

[1] The reduction of deferred tax assets is primarily due to the utilization of tax attributes for transition tax related to the Tax Act as well as the reduction of the U.S. federal corporate tax rate from 35% to 21% beginning in 2018.