Selected Quarterly Financial Data (unaudited) (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 94,651	$ 90,262	$ 79,643	$ 79,242	$ 82,077	$ 71,882	$ 58,756	$ 55,530	$ 343,798	$ 268,245	$ 197,892
Gross margin	63,016	49,765	45,637	48,670	49,770	46,565	37,299	36,902	207,088	170,536	128,647
Net income	$ (2,071)	$ 422	$ 2,276	$ 4,580	$ 6,341	$ 3,843	$ 3,650	$ 3,463	$ 5,207	$ 17,297	$ 19,933
Earnings per share
Basic (in dollars per share)	$ (0.04)	$ 0.01	$ 0.04	$ 0.09	$ 0.12	$ 0.07	$ 0.07	$ 0.06	$ 0.10	$ 0.33	$ 0.37
Diluted (in dollars per share)	$ (0.04)	$ 0.01	$ 0.04	$ 0.09	$ 0.12	$ 0.07	$ 0.07	$ 0.06	$ 0.10	$ 0.32	$ 0.36