Revenue Data by Customer Type (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018 USD ($) distribution_channel	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) distribution_channel	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Revenue, Major Customer [Line Items]
Number of primary distribution channels | distribution_channel	2								2
Net sales	$ 92,586	$ 86,959	$ 95,417	$ 84,149	$ 87,857	$ 84,000	$ 80,487	$ 68,795	$ 359,111	$ 321,139	$ 221,712
Direct Customers
Revenue, Major Customer [Line Items]
Net sales									343,464	286,742	176,485
Distributors
Revenue, Major Customer [Line Items]
Net sales									15,647	27,431	33,501
Other
Revenue, Major Customer [Line Items]
Net sales									$ 0	$ 6,966	$ 11,726