Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
Net sales	$ 78,529	$ 59,695	$ 199,457	$ 155,934
Cost of sales	36,667	29,039	91,251	71,389
Gross profit	41,862	30,656	108,206	84,545
Operating expenses:
Selling and marketing	24,711	20,052	59,890	48,451
General and administrative	7,203	4,293	15,434	9,871
Research and development	3,375	2,379	7,009	4,686
Total operating expenses	35,289	26,724	82,333	63,008
Operating income	6,573	3,932	25,873	21,537
Other income (expense):
Interest income	68	59	122	103
Interest expense	(514)	(6)	(980)	(11)
Other, net	(136)	(281)	(260)	(397)
Total other expense, net	(582)	(228)	(1,118)	(305)
Income from continuing operations before income taxes	5,991	3,704	24,755	21,232
Income tax expense	2,295	1,485	9,473	8,154
Income from continuing operations	3,696	2,219	15,282	13,078
Discontinued operations:
Loss from discontinued operations before income taxes	(180)	(160)	(304)	(313)
Income tax expense (benefit) from discontinued operations	(14)	(365)	4	(391)
Income (loss) from discontinued operations	(166)	205	(308)	78
Net income	$ 3,530	$ 2,424	$ 14,974	$ 13,156
Earnings Per Share, Basic [Abstract]
Basic income per share from continuing operations (in dollars per share)	$ 0.12	$ 0.07	$ 0.49	$ 0.42
Basic loss per share from discontinued operation (in dollars per share)	(0.01)	0.01	(0.01)	0.00
Basic net income per share (in dollars per share)	0.11	0.08	0.48	0.42
Earnings Per Share, Diluted [Abstract]
Diluted income per share from continuing operations (in dollars per share)	0.12	0.07	0.49	0.41
Diluted loss per share from discontinued operation (in dollars per share)	(0.01)	0.01	(0.01)	0.00
Diluted net income per share (in dollars per share)	$ 0.11	$ 0.08	$ 0.48	$ 0.41
Shares used in per share calculations:
Basic (in shares)	31,072	31,485	31,044	31,441
Diluted (in shares)	31,335	31,791	31,315	31,801