PROVISION FOR INCOME TAXES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Loss Carryforwards [Line Items]
Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net	$ 0	$ (189)	$ 815
U.S. and foreign components of income before income taxes [Abstract]
U.S. operations	(880)	(2,113)	(5,064)
Foreign operations	49,802	41,531	61,878
INCOME BEFORE INCOME TAXES	48,922	39,418	56,814
Current provision:
Federal	0	443	(1,234)
State	0	83	(137)
Foreign	1,638	5,407	3,094
Current provision	1,638	5,933	1,723
Deferred provision (benefit):
Federal	(197)	(1,699)	(3,279)
State	(27)	(57)	(284)
Foreign	(382)	(3,906)	(890)
Deferred provision (benefit)	(606)	(5,662)	(4,453)
Total	$ 1,032	$ 271	$ (2,730)
Effective income tax rate reconciliation [Abstract]
Provision computed at Federal statutory rate	35.00%	35.00%	35.00%
Business tax credits	(6.00%)	(6.80%)	(5.50%)
Stock-based compensation	2.20%	0.80%	(2.90%)
Foreign income taxed at different rate	(33.10%)	(33.10%)	(28.60%)
IRS audit settlement	0.00%	0.00%	(5.80%)
Valuation allowance	1.80%	2.60%	2.00%
Other	2.20%	2.20%	1.00%
Total	2.10%	0.70%	(4.80%)
Components of deferred income tax asset [Abstract]
Other reserves and accruals	$ 1,880	$ 1,573
Tax credit carry-forwards	26,895	22,826
Stock compensation	5,760	5,945
Capital losses	10,585	11,490
Net operating loss	2,671	3,677
Deferred Tax Assets, Other	174	0
Valuation allowance	(27,489)	(26,918)
Deferred tax assets, net of valuation allowance	20,476	18,593
Depreciation	(2,322)	(2,968)
Unremitted earnings	(7,019)	(4,626)
Other	0	(447)
Deferred tax liabilities	(9,341)	(8,041)
Net deferred tax asset	11,135	10,552
Reconciliation of the Beginning and Ending Amount of Unrecognized Tax Benefits [Roll Forward]
Unrecognized Tax Benefits, Balance at beginning of period	13,560	11,160	$ 12,694
Gross Increases for Tax Positions of Current Year	1,856	3,063	2,117
Gross Decrease for Tax Positions of Prior Years	(23)	(663)
Gross Increases for Tax Positions of Prior Years			710
Settlements	0	0	(4,361)
Lapse of Statute of Limitations	0	0	0
Unrecognized Tax Benefits, Balance at end of period	15,393	13,560	11,160
Unrecognized tax benefits [Abstract]
Undistributed earnings of the Company's foreign subsidiaries	265,000
Unrecognized Tax Benefits, Balance at end of period	15,393	13,560	11,160
Income tax benefit that would be recorded if unrecognized tax benefits are recognized	9,300
Income tax interest and penalties accrued	100	$ 100
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	31,300
State and Local Jurisdiction [Member] | California Taxing Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	45,500
Research Tax Credit Carryforward [Member] | Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforward, amount	14,900
Research Tax Credit Carryforward [Member] | State and Local Jurisdiction [Member] | California Taxing Authority [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforward, amount	18,700
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	700
Research Tax Credit Carryforward [Member] | Foreign Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforward, amount	$ 2,100
2007 through 2009 [Member] | Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Income tax liability (refund) adjustment from settlement with taxing authority			(3,300)
Reconciliation of the Beginning and Ending Amount of Unrecognized Tax Benefits [Roll Forward]
Settlements			(4,100)
2007 through 2009 [Member] | Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Income tax liability (refund) adjustment from settlement with taxing authority			(2,800)
2007 through 2009 [Member] | State and Local Jurisdiction [Member] | Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Income tax liability (refund) adjustment from settlement with taxing authority			$ (500)