Segment Information - Net Sales by Campaign Target 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]
Total Revenues	$ 34,796	$ 34,286	$ 66,212	$ 64,258
Customers by Campaign Target Area [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenues	34,796	34,286	66,212	64,258
North America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenues	21,106	23,353	40,855	43,631
North America [Member] | Customers by Campaign Target Area [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenues	21,106	23,353	40,855	43,631
International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenues	13,690	10,933	25,357	20,627
International [Member] | Customers by Campaign Target Area [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenues	$ 13,690	$ 10,933	$ 25,357	$ 20,627