Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Net sales	$ 459,955	$ 453,042	$ 433,823
Cost of sales	100,607	96,628	93,037
Gross profit	359,348	356,414	340,786
Sales and marketing	223,676	205,527	198,370
General and administrative	85,607	83,251	71,905
Research and development	34,637	33,218	29,700
Acquisition-related amortization and remeasurement	34,212	4,324
Operating income (loss)	(18,784)	30,094	40,811
Interest expense, net	(122)	(828)	(416)
Other expense, net	(8,143)	(6,381)	(4,004)
Income (loss) before income taxes	(27,049)	22,885	36,391
Income tax expense	(1,413)	(9,074)	(29,100)
Net income (loss) from continuing operations	(28,462)	13,811	7,291
Discontinued operations (Note 12)
Loss from discontinued operations			(1,759)
Income tax benefit			691
Net loss from discontinued operations			(1,068)
Net income (loss)	$ (28,462)	$ 13,811	$ 6,223
Net income (loss) per common share—basic
Net income (loss) from continuing operations	$ (1.51)	$ 0.73	$ 0.40
Net loss from discontinued operations			(0.06)
Net income (loss) per common share—basic	(1.51)	0.73	0.34
Net income (loss) per common share—diluted
Net income (loss) from continuing operations	(1.51)	0.72	0.39
Net loss from discontinued operations			(0.05)
Net income (loss) per common share—diluted	$ (1.51)	$ 0.72	$ 0.34
Weighted average number of common shares:
Basic	18,903,289	18,494,002	18,117,405
Diluted	18,903,289	18,911,610	18,498,745
Other comprehensive income (loss), before tax
Unrealized gain (loss) on debt security	$ (2,593)	$ 1,770	$ 3,830
Reclassification adjustment for amortization of historical unrealized gains on debt security	(1,034)
Reclassification adjustment for loss on debt security in net income	(5,193)		5,585
Currency translation adjustment	(653)	(1,823)	4,552
Other comprehensive income (loss), before tax	(9,473)	(53)	13,967
Income tax benefit (expense) related to items of other comprehensive income (loss)	2,201	(438)	(3,600)
Other comprehensive income (loss), net of tax	(7,272)	(491)	10,367
Comprehensive income (loss)	$ (35,734)	$ 13,320	$ 16,590