Condensed Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2013	Jun. 30, 2012	Jun. 29, 2013	Jun. 30, 2012
Condensed Consolidated Statements of Income
Revenues	$ 141,543	$ 135,670	$ 286,918	$ 261,372
Cost of revenues	52,770	52,868	110,773	103,474
Gross margin	88,773	82,802	176,145	157,898
Operating expenses:
Research and development	37,387	34,245	74,969	67,175
Selling, general and administrative	32,357	32,178	61,510	57,580
Operating expenses	69,744	66,423	136,479	124,755
Operating income	19,029	16,379	39,666	33,143
Other income (expense):
Interest income	152	363	487	860
Interest expense	(831)	(32)	(1,673)	(65)
Other income (expense), net	114	1,079	62	968
Income before income taxes	18,464	17,789	38,542	34,906
Provision (benefit) for income taxes	5,852	(2,720)	5,896	77
Net income	$ 12,612	$ 20,509	$ 32,646	$ 34,829
Earnings per share:
Basic (in dollars per share)	$ 0.30	$ 0.48	$ 0.77	$ 0.82
Diluted (in dollars per share)	$ 0.29	$ 0.47	$ 0.76	$ 0.80
Weighted-average common shares outstanding:
Basic (in shares)	42,552	42,655	42,370	42,556
Diluted (in shares)	43,269	43,423	43,191	43,637