Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Revenue	$ 136,022	$ 120,010	$ 112,963
Cost of sales	65,708	65,286	63,012
Gross profit	70,314	54,724	49,951
Operating expenses:
Research and development	13,821	10,961	11,017
Selling, general and administrative	43,209	36,430	31,377
Total operating expenses	57,030	47,391	42,394
Income from operations	13,284	7,333	7,557
Other income (expense):
Interest income, net	29	44	52
Other, net	(649)	(296)	(801)
Total other income (expense), net	(620)	(252)	(749)
Income before income taxes	12,664	7,081	6,808
Income tax expense (benefit)	2,734	(6,337)	709
Net income	$ 9,930	$ 13,418	$ 6,099
Basic net income per share	$ 0.61	$ 0.91	$ 0.43
Diluted net income per share	$ 0.59	$ 0.89	$ 0.42
Shares used in per share calculations:
Basic	16,323	14,792	14,182
Diluted	16,828	15,150	14,390