CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Income Statement [Abstract]
Net revenues	$ 560,041	[1]	$ 479,741	[1]	$ 387,126	[1]
Cost of revenues	143,653		118,458		83,709
Gross profit	416,388		361,283		303,417
Operating expenses:
Sales and marketing	152,041		142,174		114,013
General and administrative	95,840		89,152		64,790
Research and development	42,869		37,154		25,997
Impairment of goodwill	36,591		0		0
Litigation settlement costs	0		0		4,549
Insurance Recoveries	0		0		(8,666)
Amortization of acquired intangible assets	3,455		2,443		0
Total operating expenses	330,796		270,923		200,683
Income from operations	85,592		90,360		102,734
Interest income	757		552		555
Other Nonoperating Income (Expense)	(2,053)		(971)		(1,286)
Net income before provision for income taxes	84,296		89,941		102,003
Provision for income taxes	25,605		23,225		27,750
Net income	$ 58,691		$ 66,716		$ 74,253
Net income per share:
Basic (usd per share)	$ 0.73		$ 0.86		$ 0.98
Diluted (usd per share)	$ 0.71		$ 0.83		$ 0.95
Shares used in computing net income per share:
Basic (shares)	80,529		77,988		75,825
Diluted (shares)	83,040		80,294		78,080

[1] Revenues are attributed to countries based on location of where revenue is recognized.