Condensed Consolidated Income Statements (Unaudited) (USD $)
In Thousands, except Per Share data, unless otherwise specified
 3 Months Ended 6 Months Ended
Jun. 28, 2014
Jun. 29, 2013
Jun. 28, 2014
Jun. 29, 2013
Revenue:        
Product and maintenance $ 354,468 $ 337,983 $ 711,818 $ 666,254
Services 24,320 24,498 45,520 50,493
Total revenue 378,788 362,481 757,338 716,747
Costs and Expenses:        
Cost of product and maintenance 37,707 28,095 79,904 57,942
Cost of services 16,706 15,148 31,608 33,492
Marketing and sales 98,611 95,277 196,934 185,679
Research and development 152,672 136,395 299,138 260,479
General and administrative 32,042 34,441 60,786 64,251
Amortization of acquired intangibles 5,579 5,327 10,789 9,118
Restructuring and other charges (credits) (26) 2,656 370 2,508
Total costs and expenses 343,291 317,339 679,529 613,469
Income from operations 35,497 45,142 77,809 103,278
Interest expense (7,369) (9,528) (14,637) (18,790)
Other income, net 1,635 2,018 5,017 4,193
Income before provision for income taxes 29,763 37,632 68,189 88,681
Provision for income taxes 6,500 28,203 11,856 643
Net income $ 23,263 $ 9,429 $ 56,333 $ 88,038
Net income per share - basic (in usd per share) $ 0.08 $ 0.03 $ 0.20 $ 0.32
Net income per share - diluted (in usd per share) $ 0.08 $ 0.03 $ 0.19 $ 0.30
Weighted average common shares outstanding - basic (in shares) 283,344 277,146 282,480 276,018
Weighted average common shares outstanding - diluted (in shares) 305,755 294,443 303,395 293,274