Inventory (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Inventory, finished goods, trial and evaluation, gross	$ 1,500	$ 1,400
Raw materials	21,808	20,789
Finished goods	25,114	18,056
Total inventory	$ 46,922	$ 38,845