Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Income Statement [Abstract]
Revenue	$ 180,298		$ 163,901		$ 351,657		$ 323,957
Cost of revenue	82,315	[1]	74,109	[1]	159,814	[1]	146,498	[1]
Gross Profit	97,983		89,792		191,843		177,459
Operating expenses:
Research and development	32,092	[1]	30,227	[1]	63,159	[1]	61,126	[1]
Sales and marketing	34,512	[1]	32,234	[1]	67,248	[1]	63,151	[1]
General and administrative	13,343	[1]	11,154	[1]	27,041	[1]	24,056	[1]
Restructuring and other (Note 11)	1,235		1,167		3,137		2,250
Amortization of identified intangibles	4,946		4,631		9,873		8,815
Total operating expenses	86,128		79,413		170,458		159,398
Income from operations	11,855		10,379		21,385		18,061
Interest and other expense, net	(422)		(1,325)		(3,346)		(755)
Income before income taxes	11,433		9,054		18,039		17,306
Provision for income taxes	(2,009)		(2,049)		(253)		(4,067)
Net income	$ 9,424		$ 7,005		$ 17,786		$ 13,239
Net income per basic common share	$ 0.20		$ 0.15		$ 0.38		$ 0.29
Net income per diluted common share	$ 0.20		$ 0.15		$ 0.37		$ 0.28
Shares used in basic per-share calculation	46,427		46,460		46,376		46,247
Shares used in diluted per-share calculation	48,254		47,814		48,149		47,599

[1] Includes stock-based compensation expense as follows: