Consolidated Statements Of Income (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended
	Oct. 01, 2011	Oct. 02, 2010	Oct. 01, 2011	Oct. 02, 2010
Consolidated Statements Of Income [Abstract]
Net sales	$ 125,598	$ 125,187	$ 384,141	$ 346,937
Cost of sales	69,815	71,452	210,810	200,471
Gross profit	55,783	53,735	173,331	146,466
Selling, general and administrative expenses	30,417	28,030	93,629	83,247
Research and development expense	11,152	9,894	31,785	28,755
Operating income	14,214	15,811	47,917	34,464
Foreign currency translation gain (loss) from sale and dissolution of subsidiaries		(554)	7,198	(554)
Interest and other expense, net	(2,348)	(2,414)	(6,377)	(6,256)
Income before income taxes	11,866	12,843	48,738	27,654
Income tax provision	1,364	239	3,555	1,717
Net income	$ 10,502	$ 12,604	$ 45,183	$ 25,937
Net income per share:
Basic	$ 0.28	$ 0.34	$ 1.21	$ 0.71
Diluted	$ 0.27	$ 0.34	$ 1.17	$ 0.69
Shares used in per share calculations:
Basic	37,543	36,722	37,342	36,594
Diluted	38,571	37,579	38,732	37,529