Condensed Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 30, 2013	Mar. 31, 2012
Condensed Consolidated Statements of Income
Revenues	$ 145,375	$ 125,702
Cost of revenues	58,003	50,606
Gross margin	87,372	75,096
Operating expenses:
Research and development	37,582	32,930
Selling, general and administrative	29,153	25,402
Operating expenses	66,735	58,332
Operating income	20,637	16,764
Other income (expense):
Interest income	335	497
Interest expense	(842)	(33)
Other income (expense), net	(52)	(111)
Income before income taxes	20,078	17,117
Provision for income taxes	44	2,797
Net income	$ 20,034	$ 14,320
Earnings per share:
Basic (in dollars per share)	$ 0.47	$ 0.34
Diluted (in dollars per share)	$ 0.46	$ 0.33
Weighted-average common shares outstanding:
Basic (in shares)	42,186	42,458
Diluted (in shares)	43,110	43,850