Quarterly Financial Data - Condensed Consolidated Statement of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 121,494	$ 113,499	$ 115,850	$ 109,112	$ 121,078	$ 111,708	$ 111,547	$ 108,709	$ 459,955	$ 453,042	$ 433,823
Cost of sales	26,191	24,896	25,812	23,708	25,626	24,020	22,835	24,147	100,607	96,628	93,037
Gross profit	95,303	88,603	90,038	85,404	95,452	87,688	88,712	84,562	359,348	356,414	340,786
Operating expense	91,208	107,485	89,587	89,852	83,050	83,781	82,797	76,692	378,132	326,320
Operating income (loss)	4,095	(18,882)	451	(4,448)	12,402	3,907	5,915	7,870	(18,784)	30,094	40,811
Net income (loss) from continuing operations	11,686	(40,498)	(547)	897	8,871	(1,211)	925	5,226	(28,462)	13,811	7,291
Net income (loss)	$ 11,686	$ (40,498)	$ (547)	$ 897	$ 8,871	$ (1,211)	$ 925	$ 5,226	$ (28,462)	$ 13,811	$ 6,223
Net income (loss) per common share — basic:
Net income (loss) from continuing operations	$ 0.61	$ (2.14)	$ (0.03)	$ 0.05	$ 0.47	$ (0.07)	$ 0.05	$ 0.28	$ (1.51)	$ 0.73	$ 0.40
Net income (loss)	0.61	(2.14)	(0.03)	0.05	0.47	(0.07)	0.05	0.28	(1.51)	0.73	0.34
Net income (loss) per common share — diluted:
Net income (loss) from continuing operations	0.60	(2.14)	(0.03)	0.05	0.46	(0.07)	0.05	0.27	(1.51)	0.72	0.39
Net income (loss)	$ 0.60	$ (2.14)	$ (0.03)	$ 0.05	$ 0.46	$ (0.07)	$ 0.05	$ 0.27	$ (1.51)	$ 0.72	$ 0.34