Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net sales:
Product	$ 268,979	$ 233,141	$ 508,314	$ 451,751
Software maintenance	21,931	20,143	43,729	39,383
GSA accrual	1,349		1,349
Total net sales	292,259	253,284	553,392	491,134
Cost of sales:
Product	69,787	54,803	129,578	105,761
Software maintenance	1,064	1,083	2,621	2,601
Total cost of sales	70,851	55,886	132,199	108,362
Gross profit	221,408	197,398	421,193	382,772
Operating expenses:
Sales and marketing	110,756	96,197	210,808	183,352
Research and development	54,286	47,027	108,301	89,895
General and administrative	21,502	21,232	42,876	40,071
Total operating expenses	186,544	164,456	361,985	313,318
Operating income	34,864	32,942	59,208	69,454
Other income:
Interest income	132	344	362	685
Net foreign exchange (loss)	(1,016)	(486)	(1,904)	(709)
Other income (expense), net	151	(571)	255	(125)
Income before income taxes	34,131	32,229	57,921	69,305
Provision for income taxes	7,690	5,681	12,838	12,296
Net income	$ 26,441	$ 26,548	$ 45,083	$ 57,009
Basic earnings per share	$ 0.22	$ 0.22	$ 0.37	$ 0.48
Weighted average shares outstanding - basic	121,801	119,736	121,360	119,218
Diluted earnings per share	$ 0.22	$ 0.22	$ 0.37	$ 0.47
Weighted average shares outstanding - diluted	122,759	121,161	122,376	120,810
Dividends declared per share	$ 0.14	$ 0.10	$ 0.28	$ 0.20