Condensed Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 29, 2014	Mar. 30, 2013
Condensed Consolidated Statements of Income
Revenues	$ 145,691	$ 145,375
Cost of revenues	58,586	58,003
Gross margin	87,105	87,372
Operating expenses:
Research and development	42,485	37,582
Selling, general and administrative	34,611	29,153
Operating expenses	77,096	66,735
Operating income	10,009	20,637
Other income (expense):
Interest income	302	335
Interest expense	(798)	(842)
Other income (expense), net	67	(52)
Income before income taxes	9,580	20,078
Provision for income taxes	1,470	44
Net income	$ 8,110	$ 20,034
Earnings per share:
Basic (in dollars per share)	$ 0.19	$ 0.47
Diluted (in dollars per share)	$ 0.18	$ 0.46
Weighted-average common shares outstanding:
Basic (in shares)	43,081	42,186
Diluted (in shares)	44,056	43,110