QUARTERLY RESULTS (UNAUDITED) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended					12 Months Ended			3 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013
Operating expenses [Abstract]
Net revenues	$ 128,196	$ 142,429	$ 124,644	$ 134,982	$ 147,103	$ 530,251	$ 563,412	$ 635,703
Cost of revenues	50,548	52,788	50,420	50,665	59,801	204,471	223,909
Amortization of intangible assets	0	0	0	50	158	50	1,468
Gross profit	77,648	89,641	74,224	84,267	87,144	325,780	339,503
Research and development	23,212	22,154	22,070	22,954	24,556	90,390	95,249
Marketing and selling	34,527	31,410	34,297	32,815	34,566	133,049	133,890
General and administrative	22,222	20,644	19,984	18,331	23,135	81,181	77,578
Amortization of intangible assets	375	373	398	480	667	1,626	2,648
Restructuring (recoveries) costs, net	0	0	(165)	0	2,491	(165)	5,370
Total operating expenses	80,336	74,581	76,584	74,580	85,415	306,081	314,735
Operating (loss) income	(2,688)	15,060	(2,360)	9,687	1,729	19,699	24,768
Other (expense) income, net	(1,620)	(455)	(357)	(351)	192	(1,138)	343
(Loss) income before income taxes	(4,308)	14,605	(2,717)	9,336	1,921	16,916	24,092	51,136
Provision for income taxes	761	365	622	440	792	2,188	2,939	4,049
Net (loss) income	(5,069)	14,240	(3,339)	8,896	1,129	14,728	21,153
(Loss) income per share – basic	$ (0.13)	$ 0.36	$ (0.09)	$ 0.23	$ 0.03	$ 0.38	$ 0.54
(Loss) income per share – diluted	$ (0.13)	$ 0.36	$ (0.09)	$ 0.23	$ 0.03
Weighted Average Number of Shares Outstanding, Basic (in shares)	39,234	39,133	39,119	39,099	39,080	39,147	39,044
Weighted Average Number of Shares Outstanding, Diluted (in shares)	39,966	39,201	39,119	39,122	39,111	39,267	39,070
As Restated [Member]
Operating expenses [Abstract]
Net revenues									138,893	141,345	136,071
Cost of revenues									56,055	54,294	52,291
Amortization of intangible assets									158	501	651
Gross profit									82,680	86,550	83,129
Research and development									23,239	23,847	23,607
Marketing and selling									31,512	33,903	33,909
General and administrative									22,715	16,131	15,597
Amortization of intangible assets									660	658	663
Restructuring (recoveries) costs, net									688	1,918	273
Total operating expenses									78,814	76,457	74,049
Operating (loss) income									3,866	10,093	9,080
Other (expense) income, net									(363)	(247)	(258)
(Loss) income before income taxes									3,503	9,846	8,822
Provision for income taxes									921	669	557
Net (loss) income									$ 2,582	$ 9,177	$ 8,265
(Loss) income per share – basic									$ 0.07	$ 0.24	$ 0.21
(Loss) income per share – diluted									$ 0.07	$ 0.23	$ 0.21
Weighted Average Number of Shares Outstanding, Basic (in shares)									39,075	39,040	38,977
Weighted Average Number of Shares Outstanding, Diluted (in shares)									39,076	39,069	39,034