Condensed Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jul. 02, 2011	Jun. 30, 2012	Jul. 02, 2011
Revenues	$ 135,670	$ 126,197	$ 261,372	$ 245,833
Cost of revenues	52,868	49,985	103,474	97,463
Gross margin	82,802	76,212	157,898	148,370
Operating expenses:
Research and development	34,245	34,173	67,175	69,533
Selling, general and administrative	32,178	26,055	57,580	57,914
Operating expenses	66,423	60,228	124,755	127,447
Operating income	16,379	15,984	33,143	20,923
Other income (expense):
Interest income	363	473	860	1,044
Interest expense	(32)	(5)	(65)	(10)
Other income (expense), net	1,079	164	968	373
Income before income taxes	17,789	16,616	34,906	22,330
Provision (benefit) for income taxes	(2,720)	3,244	77	10,918
Net income	$ 20,509	$ 13,372	$ 34,829	$ 11,412
Earnings per share:
Basic (in dollars per share)	$ 0.48	$ 0.30	$ 0.82	$ 0.26
Diluted (in dollars per share)	$ 0.47	$ 0.29	$ 0.80	$ 0.25
Weighted-average common shares outstanding:
Basic (in shares)	42,655	44,602	42,556	44,435
Diluted (in shares)	43,423	45,951	43,637	45,998