Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net sales	$ 92,586	$ 86,959	$ 95,417	$ 84,149	$ 87,857	$ 84,000	$ 80,487	$ 68,795	$ 359,111	$ 321,139	$ 221,712
Gross profit	82,183	79,604	86,147	74,791	78,455	74,697	72,002	60,766	322,725	285,920	190,774
Income tax provision (expense) benefit	(27,497)	(650)	13	1,552	(9,537)	30,436	(980)	(280)	(26,582)	19,639	(155)
Net income (loss)	$ (36,224)	$ (178)	$ 1,804	$ 4,619	$ 4,276	$ 44,051	$ 10,402	$ 5,998	$ (29,979)	$ 64,727	$ 390
Net income (loss) per common share - basic (in dollars per share)	$ (0.34)	$ 0	$ 0.02	$ 0.04	$ 0.04	$ 0.41	$ 0.10	$ 0.06	$ (0.28)	$ 0.61	$ 0.00
Net income (loss) per common share - diluted (in dollars per share)	$ (0.34)	$ 0	$ 0.02	$ 0.04	$ 0.04	$ 0.37	$ 0.09	$ 0.05	$ (0.28)	$ 0.56	$ 0
Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net sales						$ 84,573	$ 76,412	$ 72,607			$ 245,015
Gross profit						74,974	67,781	63,864			212,608
Income tax provision (expense) benefit						4,384	1,005	(1,713)			(6,133)
Net income (loss)						$ 17,457	$ 8,069	$ 4,327			$ 11,974
Net income (loss) per common share - basic (in dollars per share)						$ 0.16	$ 0.08	$ 0.04			$ 0.11
Net income (loss) per common share - diluted (in dollars per share)						$ 0.15	$ 0.07	$ 0.04			$ 0.11