Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Net sales	$ 80,818	$ 70,690	$ 280,275	$ 226,624
Cost of sales	41,601	34,481	132,852	105,870
Gross profit	39,217	36,209	147,423	120,754
Operating expenses:
Selling and marketing	21,394	21,742	81,284	70,193
General and administrative	6,177	5,505	21,611	15,376
Research and development	3,435	2,573	10,444	7,259
Total operating expenses	31,006	29,820	113,339	92,828
Operating income	8,211	6,389	34,084	27,926
Other income (expense):
Interest income	60	61	182	164
Interest expense	(489)	(6)	(1,469)	(17)
Other, net	211	(15)	(49)	(412)
Total other income (expense), net	(218)	40	(1,336)	(265)
Income from continuing operations before income taxes	7,993	6,429	32,748	27,661
Income tax expense	148	2,556	9,621	10,710
Income from continuing operations	7,845	3,873	23,127	16,951
Discontinued operations:
Loss from discontinued operations before income taxes	(308)	(159)	(612)	(472)
Income tax benefit from discontinued operations	(57)	(14)	(53)	(405)
Loss from discontinued operations	(251)	(145)	(559)	(67)
Net income	$ 7,594	$ 3,728	$ 22,568	$ 16,884
Earnings Per Share, Basic [Abstract]
Basic income per share from continuing operations (in dollars per share)	$ 0.25	$ 0.12	$ 0.74	$ 0.54
Basic loss per share from discontinued operation (in dollars per share)	(0.01)	0.00	(0.02)	0.00
Basic net income per share (in dollars per share)	0.24	0.12	0.73	0.54
Earnings Per Share, Diluted [Abstract]
Diluted income per share from continuing operations (in dollars per share)	0.25	0.12	0.74	0.53
Diluted loss per share from discontinued operation (in dollars per share)	(0.01)	0.00	(0.02)	0.00
Diluted net income per share (in dollars per share)	$ 0.24	$ 0.12	$ 0.72	$ 0.53
Shares used in per share calculations:
Basic (in shares)	31,118	31,272	31,069	31,386
Diluted (in shares)	31,385	31,527	31,340	31,702