Condensed Consolidated Income Statements (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016
Revenue:
Product and maintenance	$ 451,229	$ 415,370	$ 1,346,483	$ 1,247,077
Services	34,169	30,850	94,827	100,026
Total revenue	485,398	446,220	1,441,310	1,347,103
Costs and Expenses:
Cost of product and maintenance	34,825	38,740	117,371	125,881
Cost of services	19,657	17,867	59,735	54,563
Marketing and sales	104,263	96,793	311,507	297,103
Research and development	206,568	191,547	600,755	553,824
General and administrative	36,302	30,441	100,892	95,129
Amortization of acquired intangibles	3,453	3,889	11,145	14,206
Restructuring and other charges (credits)	(55)	101	(2,772)	14,613
Total costs and expenses	405,013	379,378	1,198,633	1,155,319
Income from operations	80,385	66,842	242,677	191,784
Interest expense	(6,225)	(6,053)	(18,952)	(17,306)
Other income, net	12,387	2,836	14,370	10,441
Income before provision (benefit) for income taxes	86,547	63,625	238,095	184,919
Provision (benefit) for income taxes	5,390	(1,087)	19,552	20,310
Net income	$ 81,157	$ 64,712	$ 218,543	$ 164,609
Net income per share - basic (in usd per share)	$ 0.30	$ 0.23	$ 0.80	$ 0.57
Net income per share - diluted (in usd per share)	$ 0.29	$ 0.23	$ 0.78	$ 0.56
Weighted average common shares outstanding - basic (in shares)	273,156	280,622	271,739	288,476
Weighted average common shares outstanding - diluted (in shares)	281,400	287,473	279,554	295,369