Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Net sales	$ 335,764	$ 274,447	$ 218,803
Cost of sales	162,530	133,872	112,326
Gross profit	173,234	140,575	106,477
Operating expenses:
Selling and marketing	101,618	81,059	66,486
General and administrative	21,441	22,131	18,705
Research and development	9,904	7,231	5,562
Total operating expenses	132,963	110,421	90,753
Operating income	40,271	30,154	15,724
Other income (expense):
Interest income	218	63	14
Interest expense	(22)	(25)	(36)
Other, net	(445)	32	337
Total other income (expense), net	(249)	70	315
Income from continuing operations before income taxes	40,022	30,224	16,039
Income tax expense (benefit)	13,219	9,841	(32,085)
Income from continuing operations	26,803	20,383	48,124
Discontinued operations:
Loss from discontinued operations before income taxes	(601)	(1,134)	(559)
Income tax expense (benefit) of discontinued operations	(400)	454	(389)
Loss from discontinued operations	(201)	(1,588)	(170)
Net income	$ 26,602	$ 18,795	$ 47,954
Basic net income per share
Basic income per share from continuing operations (in dollars per share)	$ 0.86	$ 0.65	$ 1.55
Basic income (loss) per share from discontinued operations (in dollars per share)	(0.01)	(0.05)	(0.01)
Basic net income per share (in dollars per share)	0.85	0.60	1.54
Diluted net income per share
Diluted income per share from continuing operations (in dollars per share)	0.85	0.64	1.53
Diluted income (loss) per share from discontinued operations (in dollars per share)	(0.01)	(0.05)	(0.01)
Diluted net income per share (in dollars per share)	$ 0.84	$ 0.59	$ 1.52
Shares used in per share calculations:
Basic (in shares)	31,288	31,253	31,072
Diluted (in shares)	31,589	31,688	31,457