INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
U.S. federal income tax rate
U.S. federal income tax rate (as a percent)									35.00%
Difference in income tax provision from amount computed by applying U.S. federal income tax rate to loss before income taxes
U.S. federal income tax provision (benefit) at statutory rate									$ 1,091	$ 4,622	$ 5,720
Adjustment to reserves in prior years									0	0	4,418
Fines and penalties									(26)	(112)	2,387
Research and development credit									0	336	242
Lobbying expenses									243	266	209
Stock based compensation expense									(32)	(43)	(176)
Other									(1,193)	(2,050)	(6,069)
State income tax expense, net of federal benefit									(20)	385	(4,828)
Change in valuation allowance									1,832	1,000	(69,937)
Total provision (benefit) for income taxes	$ (1,879)	$ (15)	$ 1,849	$ 1,940	$ 968	$ 413	$ 433	$ 2,590	1,895	4,404	(68,034)
Deferred tax assets:
Net operating loss carryforwards	47,793				50,952				47,793	50,952
Research and development tax credits	8,574				7,382				8,574	7,382
AMT and other tax credits	1,034				850				1,034	850
Accrued expenses	12,605				10,924				12,605	10,924
Reserves and other	3,227				3,119				3,227	3,119
Gross deferred tax assets	73,233				73,227				73,233	73,227
Valuation allowance	(3,071)				(1,000)				(3,071)	(1,000)
Total deferred tax assets	70,162				72,227				70,162	72,227
Deferred tax liabilities:
Fixed assets	(4,569)				(5,786)				(4,569)	(5,786)
Prepaid expenses	(1,397)				(1,275)				(1,397)	(1,275)
Total deferred tax liabilities	(5,966)				(7,061)				(5,966)	(7,061)
Total deferred tax assets, net	64,196				65,166				$ 64,196	65,166
Assessment of deferred tax asset, term									3 years
Interest and penalties accrued on tax contingencies	236				$ 184				$ 236	184
Income tax holiday									23	$ 15	$ 3
Indefinitely reinvested foreign earnings	366								366
Operating Loss Carryforwards, Deductions and Credits
Deferred tax assets:
Valuation allowance	(1,500)								(1,500)
Unrealized Capital Losses
Deferred tax assets:
Valuation allowance	(1,600)								(1,600)
Stock option deductions
Difference in income tax provision from amount computed by applying U.S. federal income tax rate to loss before income taxes
Total provision (benefit) for income taxes									9,400
Deferred tax liabilities:
Net operating loss carryforwards	24,500								24,500
Internal Revenue Service (IRS)
Deferred tax assets:
Research and development tax credits	9,200								9,200
Deferred tax liabilities:
Net operating loss carryforwards	149,300								149,300
State and local jurisdictions
Deferred tax assets:
Research and development tax credits	4,700								4,700
Deferred tax liabilities:
Net operating loss carryforwards	139,400								139,400
International operations | 5 Year Carryforward
Deferred tax liabilities:
Net operating loss carryforwards	630								630
International operations | Indefinite Life
Deferred tax liabilities:
Net operating loss carryforwards	$ 528								$ 528