CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
NET REVENUES		$ 89,188	$ 103,081
COST OF REVENUES		43,714	49,537
GROSS PROFIT		45,474	53,544
OPERATING EXPENSES:
Research and development		17,946	17,481
Sales and marketing		13,017	13,088
General and administrative		8,390	9,014
Total operating expenses		39,353	39,583
INCOME FROM OPERATIONS		6,121	13,961
OTHER INCOME		1,152	836
INCOME BEFORE INCOME TAXES		7,273	14,797
PROVISION FOR INCOME TAXES		40	597
NET INCOME		$ 7,233	$ 14,200
EARNINGS PER SHARE:
Basic (in dollars per share)		$ 0.25	$ 0.48
Diluted (in dollars per share)	[1]	$ 0.25	$ 0.46
SHARES USED IN PER SHARE CALCULATION:
Basic (in shares)		28,951	29,799
Diluted (in shares)		29,446	30,552

[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 2019 and 2018 calculations as the shares were not contingently issuable as of the end of the reporting periods.