CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Income Statement [Abstract]
NET REVENUES		$ 85,326	$ 82,557
COST OF REVENUES		42,379	40,265
GROSS PROFIT		42,947	42,292
OPERATING EXPENSES:
Research and development		14,779	14,941
Sales and marketing		11,406	12,113
General and administrative		7,850	8,281
Total operating expenses		34,035	35,335
INCOME FROM OPERATIONS		8,912	6,957
OTHER INCOME (EXPENSE)		261	(223)
INCOME BEFORE INCOME TAXES		9,173	6,734
PROVISION FOR INCOME TAXES		330	391
NET INCOME		$ 8,843	$ 6,343
EARNINGS PER SHARE:
Basic (in dollars per share)		$ 0.31	$ 0.22
Diluted (in dollars per share)	[1]	$ 0.30	$ 0.21
SHARES USED IN PER SHARE CALCULATION:
Basic (in shares)		28,679	29,309
Diluted (in shares)		29,244	30,058

[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.