Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Net sales:
Product	$ 955,613	$ 807,386	$ 623,736
Software maintenance	81,667	65,834	52,858
GSA accrual	(13,107)	0	0
Total net sales	1,024,173	873,220	676,594
Cost of sales:
Product	235,839	195,096	164,700
Software maintenance	5,125	4,987	5,184
Total cost of sales	240,964	200,083	169,884
Gross profit	783,209	673,137	506,710
Operating expenses:
Sales and marketing	388,768	319,606	269,267
Research and development	199,071	158,149	132,974
General and administrative	82,658	67,069	57,938
Total operating expenses	670,497	544,824	460,179
Operating income	112,712	128,313	46,531
Other income (expense):
Interest income	1,319	1,391	1,629
Net foreign exchange gain (loss)	(2,755)	(2,585)	734
Other income (loss), net	(142)	993	1,351
Income before income taxes	111,134	128,112	50,245
Provision for income taxes	17,062	18,996	33,160
Net income	$ 94,072	$ 109,116	$ 17,085
Basic earnings per share	$ 0.79	$ 0.93	$ 0.15
Weighted average shares outstanding - basic	119,836	116,973	116,280
Diluted earnings per share	$ 0.78	$ 0.92	$ 0.15
Weighted average shares outstanding - diluted	121,220	118,572	117,039
Dividends declared per share	$ 0.40	$ 0.35	$ 0.32