Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Apr. 01, 2017	Apr. 02, 2016
Net sales:
Products	$ 54,033	$ 42,258
Services	3,076	2,752
Licenses	300	200
Total net sales	57,409	45,210
Cost of sales:
Cost of products sold	27,659	24,179
Cost of services	3,267	2,864
Total cost of sales	30,926	27,043
Gross profit	26,483	18,167
Operating expenses:
Research, development, and engineering	8,884	8,235
Selling, general, and administrative	14,505	11,314
Operating income (loss)	3,094	(1,382)
Interest expense	(4)	(18)
Interest and other income, net	329	173
Income (loss) before income tax	3,419	(1,227)
Income tax provision (benefit)	451	(73)
Net income (loss)	$ 2,968	$ (1,154)
Net income per share - basic (in dollars per share)	$ 0.11	$ (0.04)
Number of shares used in per share computations - basic (in shares)	27,289	26,798
Net income per share - diluted (in dollars per share)	$ 0.11	$ (0.04)
Number of shares used in per share computations - diluted (in shares)	27,678	26,798