INCOME TAXES (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010
Components of income (loss) before income taxes [Abstract]
United States	$ 60,485,000	$ 57,258,000	$ 20,069,000
Foreign	(1,158,000)	(18,250,000)	(5,201,000)
INCOME BEFORE INCOME TAXES	59,327,000	39,008,000	14,868,000
Current income tax benefit (expense):
Federal	0	226,000	(225,000)
State	(2,000)	0	0
Foreign	(8,363,000)	(6,600,000)	(4,994,000)
Current income tax benefit (expense)	(8,365,000)	(6,374,000)	(5,219,000)
Deferred income tax (expense) benefit:
Federal	(9,652,000)	(16,811,000)	0
State	575,000	(1,192,000)	0
Foreign	(31,000)	69,000	11,000
Deferred income tax expense, gross	(9,108,000)	(17,934,000)	11,000
Adjustments to the beginning-of-year valuation allowance	0	59,352,000	0
Income tax benefit (expense)	(17,473,000)	35,044,000	(5,208,000)
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%	34.00%
State income taxes, net of federal benefit	(0.40%)	(1.30%)	(2.30%)
State apportionment change	0.00%	0.30%	23.80%
U.S. federal rate change	0.00%	(3.60%)	0.00%
Effect of foreign operations	0.70%	10.90%	7.10%
Subpart F income	(4.50%)	15.60%	0.00%
Nondeductible employee compensation	0.50%	2.30%	4.20%
Research tax credits	(2.50%)	(3.40%)	0.00%
Change in valuation allowance	(0.40%)	(146.40%)	(29.30%)
Other	1.00%	0.80%	(2.50%)
Effective tax rate	29.40%	(89.80%)	35.00%
Tax Deduction	41,663,000
Tax Benefit, Loss carrforwards	10,247,000
Tax Benefit, Tax credit carryforward	37,388,000
Windfalls included in net operating loss carryforwards	72,300,000	68,600,000
Windfalls included in net operating loss carryforwards, tax benefit	25,800,000
Deferred tax asset:
Net operating loss carry forwards	2,425,000	6,280,000
Capitalized technology license	2,146,000	2,519,000
Capitalized research expenditures	12,227,000	14,012,000
Accruals and reserves	3,021,000	2,172,000
Retirement plan	3,761,000	3,315,000
Deferred revenue	541,000	1,393,000
Deferred Tax Assets, Tax Credit Carryforwards	19,395,000	26,965,000
Stock-based compensation	2,060,000	1,389,000
Other	1,589,000	1,329,000
Deferred Tax Assets, Gross	47,165,000	59,374,000
Valuation allowance	(12,372,000)	(12,598,000)
Deferred tax assets	34,793,000	46,776,000
Deferred tax liability:
Subpart F income	(3,400,000)	(6,070,000)
Deferred tax liabilities	(3,400,000)	(6,070,000)
Deferred Tax Assets, Net	31,393,000	40,706,000
Period of exemption on withholding tax on royalty payments				5 years
Withholding tax rate for royalty payments	16.50%
Deferred income tax expense	9,108,000	(41,418,000)	(11,000)
Decrease in valuation allowance	(200,000)	(57,100,000)	(4,400,000)
Federal [Member]
Reconciliation of the statutory U.S. federal tax rate to the effective tax rate [Abstract]
Tax Deduction	22,348,000
Tax Benefit, Loss carrforwards	7,822,000
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 Benefit, Tax credit carryforward	12,416,000
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, 2034
State [Member] | Research tax credit [Member]
Reconciliation of the statutory U.S. federal tax rate to the effective tax rate [Abstract]
Tax Benefit, Tax credit carryforward	2,896,000
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, 2029
Foreign [Member]
Reconciliation of the statutory U.S. federal tax rate to the effective tax rate [Abstract]
Tax Deduction	19,315,000
Tax Benefit, Loss carrforwards	2,425,000
Tax Benefit, Tax credit carryforward	22,076,000
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, 2024
South Korea [Member]
Current income tax benefit (expense):
Foreign	(8,300,000)	(6,600,000)	(4,900,000)
UDC Ireland [Member]
Deferred tax liability:
Deferred income tax expense	$ 3,400,000	$ 6,100,000