Property and Equipment - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Gross property and equipment	$ 26,270	$ 19,711
Less accumulated depreciation	(13,892)	(11,699)
Property and equipment, net	12,378	8,012
Computers and Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross property and equipment	3,204	2,801
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross property and equipment	12,223	10,331
Building and Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Gross property and equipment	$ 10,843	$ 6,579