Condensed Consolidated Income Statements (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Revenue:
Product and maintenance	$ 480,609	$ 451,407
Services	36,704	25,504
Total revenue	517,313	476,911
Costs and Expenses:
Cost of product and maintenance	41,730	43,717
Cost of services	21,479	18,075
Marketing and sales	109,148	103,347
Research and development	224,185	198,286
General and administrative	33,299	31,816
Amortization of acquired intangibles	3,630	3,856
Restructuring and other credits	(1,991)	(1,788)
Total costs and expenses	431,480	397,309
Income from operations	85,833	79,602
Interest expense	(6,975)	(6,479)
Other income (expense), net	(689)	1,059
Income before provision for income taxes	78,169	74,182
Provision for income taxes	5,284	5,923
Net income	$ 72,885	$ 68,259
Net income per share - basic (in usd per share)	$ 0.27	$ 0.25
Net income per share - diluted (in usd per share)	$ 0.26	$ 0.25
Weighted average common shares outstanding - basic (in shares)	273,773	270,173
Weighted average common shares outstanding - diluted (in shares)	281,651	277,736