CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
NET REVENUES		$ 97,169	$ 85,265	$ 182,495	$ 167,822
COST OF REVENUES		49,532	41,247	91,911	81,512
GROSS PROFIT		47,637	44,018	90,584	86,310
OPERATING EXPENSES:
Research and development		15,859	14,864	30,638	29,805
Sales and marketing		12,018	12,459	23,424	24,572
General and administrative		8,133	7,491	15,983	15,772
Total operating expenses		36,010	34,814	70,045	70,149
INCOME FROM OPERATIONS		11,627	9,204	20,539	16,161
OTHER INCOME (EXPENSE)		236	14	497	(209)
INCOME BEFORE INCOME TAXES		11,863	9,218	21,036	15,952
PROVISION FOR INCOME TAXES		598	628	928	1,019
NET INCOME		$ 11,265	$ 8,590	$ 20,108	$ 14,933
EARNINGS PER SHARE:
Basic (in dollars per share)		$ 0.39	$ 0.29	$ 0.70	$ 0.51
Diluted (in dollars per share)	[1]	$ 0.38	$ 0.29	$ 0.68	$ 0.50
SHARES USED IN PER SHARE CALCULATION:
Basic (in shares)		28,850	29,368	28,765	29,339
Diluted (in shares)		29,422	30,034	29,361	30,075

[1] The Company includes the shares underlying performance-based awards in the calculation of diluted earnings per share if the performance conditions have been satisfied as of the end of the reporting period and excludes such shares when the necessary conditions have not been met. The Company has excluded the shares underlying the outstanding performance-based awards in the 2016 and 2015 calculations as the shares were not contingently issuable as of the end of the reporting periods.