Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Net sales	$ 102,738	$ 98,679
Cost of sales	22,581	22,137
Gross profit	80,157	76,542
Sales and marketing	48,532	44,822
General and administrative	18,282	17,005
Research and development	7,424	7,640
Operating income	5,919	7,075
Interest income (expense), net	45	(38)
Other income (expense), net	(4,348)	1,833
Income before income taxes	1,616	8,870
Income tax expense	(3,924)	(4,294)
Net income (loss) from continuing operations	(2,308)	4,576
Discontinued operations (Note 6)
Loss from discontinued operations	(527)	(990)
Income tax benefit	181	254
Net loss from discontinued operations	(346)	(736)
Net income (loss)	$ (2,654)	$ 3,840
Net income (loss) per common share—basic
Net income (loss) from continuing operations	$ (0.13)	$ 0.25
Net loss from discontinued operations	(0.02)	(0.04)
Net income (loss) per common share—basic	(0.15)	0.21
Net income (loss) per common share—diluted
Net income (loss) from continuing operations	(0.13)	0.24
Net loss from discontinued operations	(0.02)	(0.04)
Net income (loss) per common share—diluted	$ (0.15)	$ 0.20
Weighted average number of common shares:
Basic	17,979,675	18,477,881
Diluted	17,979,675	18,758,751
Other comprehensive income, before tax
Unrealized gain on derivative instrument		$ 48
Unrealized loss on debt securities	$ (3,220)	(824)
Reclassification adjustment for loss on debt securities in net income	5,585
Currency translation adjustment	234	1,221
Other comprehensive income before tax	2,599	445
Income tax related to items of other comprehensive loss	(900)	275
Other comprehensive income, net of tax	1,699	720
Comprehensive income (loss)	$ (955)	$ 4,560