Condensed Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Condensed Consolidated Statements of Income
Revenues	$ 158,144	$ 146,933	$ 458,753	$ 433,851
Cost of revenues	62,033	58,772	176,874	169,545
Gross margin	96,111	88,161	281,879	264,306
Operating expenses:
Research and development	42,517	40,662	126,846	115,631
Selling, general and administrative	43,990	37,009	114,618	98,519
Operating expenses	86,507	77,671	241,464	214,150
Operating income	9,604	10,490	40,415	50,156
Other income (expense):
Interest income	231	129	733	616
Interest expense	(768)	(813)	(2,346)	(2,486)
Other income (expense), net	42	(23)	103	39
Income before income taxes	9,109	9,783	38,905	48,325
Provision for income taxes	3,501	3,252	10,908	9,148
Net income	$ 5,608	$ 6,531	$ 27,997	$ 39,177
Earnings per share:
Basic (in dollars per share)	$ 0.13	$ 0.15	$ 0.65	$ 0.92
Diluted (in dollars per share)	$ 0.13	$ 0.15	$ 0.64	$ 0.90
Weighted-average common shares outstanding:
Basic (in shares)	43,112	42,684	43,218	42,477
Diluted (in shares)	43,815	43,922	44,030	43,437