Segment Information - Net Sales to Customers by Geographic Area (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, Total	$ 34,796	$ 34,286	$ 66,212	$ 64,258
Unaffiliated Customers by Geographic Area [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, Total	34,796	34,286	66,212	64,258
United States [Member] | Unaffiliated Customers by Geographic Area [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, Total	24,197	25,813	46,634	48,063
United Kingdom [Member] | Unaffiliated Customers by Geographic Area [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, Total	4,531	3,324	8,323	6,433
Other International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, Total	13,690	10,933	25,357	20,627
Other International [Member] | Unaffiliated Customers by Geographic Area [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales, Total	$ 6,068	$ 5,149	$ 11,255	$ 9,762