SELECTED QUARTERLY INFORMATION (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Quarterly Financial Information Disclosure [Abstract]
Net revenues	$ 66,730	$ 75,063	$ 80,184	$ 76,762	$ 72,986	$ 75,452	$ 79,858	$ 71,507
Gross Profit	31,554	35,043	37,626	36,423	36,125	39,005	41,489	35,922	140,646		152,541		108,068
Net income	$ 6,326	$ 7,512	$ 10,599	$ 9,854	$ 8,929	$ 12,634	$ 15,587	$ 12,314	$ 34,291		$ 49,464		$ 23,269
Earnings per share
Basic (per share)	$ 0.23	$ 0.26	$ 0.37	$ 0.34	$ 0.32	$ 0.45	$ 0.56	$ 0.45	$ 1.2		$ 1.78		$ 0.86
Diluted (per share)	$ 0.22	$ 0.25	$ 0.35	$ 0.33	$ 0.30	$ 0.43	$ 0.53	$ 0.42	$ 1.14	[1]	$ 1.67	[1]	$ 0.82	[1]
Shares used in per share calculation
Basic (in shares)	28,077	28,799	28,938	28,628	28,134	27,894	27,844	27,470	28,609		27,837		26,920
Diluted (in shares)	29,171	29,879	30,346	30,187	29,844	29,283	29,535	29,358	29,964	[1]	29,556	[1]	28,297	[1]

[1] The Company includes the shares underlying performance-based awards in the calculation of diluted earnings per share when they become contingently issuable per ASC 260-10, Earnings per Share and excludes such shares when they are not contingently issuable. The Company has excluded all performance-based awards underlying the 2011 awards in the 2011 calculation as those shares were not contingently issuable as of the end of the period, and has included all performance-based awards underlying the 2010 and 2009 awards in the 2010 and 2009 calculation, respectively, as those shares were contingently issuable upon the satisfaction of the annual targets consisting of net revenue and non-GAAP operating earnings as of the end of the period.