Summary of Significant Accounting Policies - Components of Equipment, Molds, Furniture, and Fixtures (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Abstract]
Furniture, fixtures and office equipment	$ 2,258	$ 2,234
Production molds and equipment	15,322	10,582
Molds and tooling in process	4,023	10,150
Less accumulated depreciation	5,445	5,099
Equipment, molds, furniture and fixtures, Total	$ 16,158	$ 17,867