INCOME TAXES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2010
Components of income (loss) before income taxes [Abstract]
United States	$ 54,338	$ 60,485	$ 57,258
Foreign	(21,279)	(1,158)	(18,250)
INCOME BEFORE INCOME TAXES	33,059	59,327	39,008
Current income tax benefit (expense):
Federal	(1,018)	0	226
State	(2)	(2)	0
Foreign	(10,224)	(8,363)	(6,600)
Current income tax benefit (expense)	(11,244)	(8,365)	(6,374)
Deferred income tax (expense) benefit:
Federal	(7,145)	(9,652)	(16,811)
State	51	575	(1,192)
Foreign	(43)	(31)	69
Deferred income tax expense, gross	(7,137)	(9,108)	(17,934)
Adjustments to the beginning-of-year valuation allowance	0	0	59,352
Income tax benefit (expense)	$ (18,381)	$ (17,473)	$ 35,044
Reconciliation of the statutory U.S. federal tax rate to the effective tax rate [Abstract]
Statutory U.S. federal income tax rate	35.00%	35.00%	35.00%
State income taxes, net of federal benefit	(0.10%)	(0.40%)	(1.30%)
State apportionment change	0.00%	0.00%	0.30%
U.S. federal rate change	0.00%	0.00%	(3.60%)
Effect of foreign operations	15.20%	0.70%	10.90%
Subpart F income	0.00%	(4.50%)	15.60%
Nondeductible employee compensation	2.50%	0.50%	2.30%
Research tax credits	(4.40%)	(2.50%)	(3.40%)
Change in valuation allowance	8.40%	(0.40%)	(146.40%)
Other	(1.00%)	1.00%	0.80%
Effective tax rate	55.60%	29.40%	(89.80%)
Tax Deduction	$ 29,729
Tax Benefit, Loss carrforwards	3,716
Tax credit carryforward	38,273
Windfalls included in net operating loss carryforwards	84,900	$ 72,300
Windfalls included in net operating loss carryforwards, tax benefit	30,300
Deferred tax asset:
Net operating loss carry forwards	3,716	2,425
Capitalized technology license	3,922	2,146
Capitalized research expenditures	10,206	12,227
Accruals and reserves	6,675	3,021
Retirement plan	8,062	3,761
Deferred revenue	731	541
Tax credit carryforward	7,973	19,395
Stock-based compensation	2,012	2,060
Other	1,857	1,589
Deferred Tax Assets, Gross	45,154	47,165
Valuation allowance	(14,483)	(12,372)
Deferred tax assets	30,671	34,793
Deferred tax liability:
Subpart F income	(3,400)	(3,400)
Deferred tax liabilities	(3,400)	(3,400)
Deferred Tax Assets, Net	$ 27,271	31,393
Period of exemption on withholding tax on royalty payments				5 years
Withholding tax rate for royalty payments	16.50%
Deferred income tax expense	$ 7,137	9,108	$ (41,418)
Change in valuation allowance	(2,100)	(226)	(57,100)
Federal [Member]
Reconciliation of the statutory U.S. federal tax rate to the effective tax rate [Abstract]
Tax Deduction	0
Tax Benefit, Loss carrforwards	$ 0
Federal [Member] | Minimum [Member]
Deferred tax liability:
Loss carry forwards, expiration date	Dec. 31, 2028
Federal [Member] | Maximum [Member]
Deferred tax liability:
Loss carry forwards, expiration date	Dec. 31, 2031
Federal [Member] | Research tax credit [Member]
Reconciliation of the statutory U.S. federal tax rate to the effective tax rate [Abstract]
Tax credit carryforward	$ 11,061
Federal [Member] | Research tax credit [Member] | Minimum [Member]
Deferred tax liability:
Tax credit carryforwards, expiration date	Dec. 31, 2020
Federal [Member] | Research tax credit [Member] | Maximum [Member]
Deferred tax liability:
Tax credit carryforwards, expiration date	Dec. 31, 2035
State [Member] | Research tax credit [Member]
Reconciliation of the statutory U.S. federal tax rate to the effective tax rate [Abstract]
Tax credit carryforward	$ 2,299
State [Member] | Research tax credit [Member] | Minimum [Member]
Deferred tax liability:
Tax credit carryforwards, expiration date	Dec. 31, 2022
State [Member] | Research tax credit [Member] | Maximum [Member]
Deferred tax liability:
Tax credit carryforwards, expiration date	Dec. 31, 2030
Foreign [Member]
Reconciliation of the statutory U.S. federal tax rate to the effective tax rate [Abstract]
Tax Deduction	$ 29,729
Tax Benefit, Loss carrforwards	3,716
Tax credit carryforward	$ 24,913
Foreign [Member] | Minimum [Member]
Deferred tax liability:
Tax credit carryforwards, expiration date	Dec. 31, 2020
Foreign [Member] | Maximum [Member]
Deferred tax liability:
Tax credit carryforwards, expiration date	Dec. 31, 2025
South Korea [Member]
Current income tax benefit (expense):
Foreign	$ (9,900)	(8,300)	$ (6,600)
UDC Ireland [Member]
Deferred tax liability:
Deferred income tax expense	$ 3,400	$ 3,400