Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Net sales:
Product	$ 289,817	$ 278,530	$ 561,328	$ 537,963
Software maintenance	28,792	27,575	57,386	55,319
Total net sales	318,609	306,105	618,714	593,282
Cost of sales:
Product	79,153	75,194	154,349	149,404
Software maintenance	3,307	2,314	4,635	4,250
Total cost of sales	82,460	77,508	158,984	153,654
Gross profit	236,149	228,597	459,730	439,628
Operating expenses:
Sales and marketing	124,414	116,361	241,674	229,568
Research and development	56,913	59,839	115,175	119,179
General and administrative	26,191	25,130	51,933	49,770
Total operating expenses	207,518	201,330	408,782	398,517
Operating income	28,631	27,267	50,948	41,111
Other income:
Interest income	509	258	852	511
Net foreign exchange gain (loss)	447	(1,285)	529	(711)
Other gain(loss), net	(235)	53	197	(2,353)
Income before income taxes	29,352	26,293	52,526	38,558
Provision for income taxes	4,197	6,493	9,223	9,460
Net income	$ 25,155	$ 19,800	$ 43,303	$ 29,098
Basic earnings per share	$ 0.19	$ 0.15	$ 0.33	$ 0.23
Weighted average shares outstanding - basic	130,197	128,282	129,820	127,938
Diluted earnings per share	$ 0.19	$ 0.15	$ 0.33	$ 0.23
Weighted average shares outstanding - diluted	131,117	128,746	130,619	128,429
Dividends declared per share	$ 0.21	$ 0.20	$ 0.42	$ 0.40