Inventory - Inventory Valued at Lower of Cost (First-in, First-out) or Market, Net of Inventory Obsolescence Reserve (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Raw materials	$ 79	$ 311
Finished goods	65,219	53,569
Inventory, net	$ 65,298	$ 53,880