Condensed Consolidated Statements of Income (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
Condensed Consolidated Statements of Income
Revenues	$ 154,918	$ 141,543	$ 300,609	$ 286,918
Cost of revenues	56,255	52,770	114,841	110,773
Gross margin	98,663	88,773	185,768	176,145
Operating expenses:
Research and development	41,844	37,387	84,329	74,969
Selling, general and administrative	36,017	32,357	70,628	61,510
Operating expenses	77,861	69,744	154,957	136,479
Operating income	20,802	19,029	30,811	39,666
Other income (expense):
Interest income	200	152	502	487
Interest expense	(780)	(831)	(1,578)	(1,673)
Other income (expense), net	(6)	114	61	62
Income before income taxes	20,216	18,464	29,796	38,542
Provision for income taxes	5,937	5,852	7,407	5,896
Net income	$ 14,279	$ 12,612	$ 22,389	$ 32,646
Earnings per share:
Basic (in dollars per share)	$ 0.33	$ 0.30	$ 0.52	$ 0.77
Diluted (in dollars per share)	$ 0.32	$ 0.29	$ 0.51	$ 0.76
Weighted-average common shares outstanding:
Basic (in shares)	43,462	42,552	43,271	42,370
Diluted (in shares)	44,218	43,269	44,137	43,191