Condensed Consolidated Statements of Operations (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
Net sales:
Products	$ 53,525	$ 48,653	$ 98,628	$ 91,453
Services	5,337	4,971	9,409	9,425
Licenses	250	325	650	450
Total net sales	59,112	53,949	108,687	101,328
Cost of sales:
Cost of products sold	23,930	22,019	41,981	42,078
Cost of services	3,142	4,446	6,267	8,057
Total cost of sales	27,072	26,465	48,248	50,135
Gross profit	32,040	27,484	60,439	51,193
Operating expenses:
Research, development, and engineering	7,772	5,759	14,535	11,483
Selling, general, and administrative	11,088	10,998	21,469	20,817
Operating income	13,180	10,727	24,435	18,893
Interest expense	(2)	(5)	(5)	(11)
Interest and other income, net	(46)	106	82	113
Income before income tax	13,132	10,828	24,512	18,995
Provision for income taxes	1,961	1,100	3,141	1,400
Net income	$ 11,171	$ 9,728	$ 21,371	$ 17,595
Net income per share - basic (in dollars per share)	$ 0.42	$ 0.38	$ 0.81	$ 0.69
Number of shares used in per share computations - basic (in shares)	26,530	25,731	26,387	25,488
Net income per share - diluted (in dollars per share)	$ 0.41	$ 0.36	$ 0.78	$ 0.66
Number of shares used in per share computations - diluted (in shares)	27,387	26,888	27,247	26,561