Intangible Assets - Summary of Components of Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Finite Lived Intangible Assets [Line Items]
Total intangible assets	$ 11,574	$ 14,355
Patents [Member]
Finite Lived Intangible Assets [Line Items]
Total intangible assets	5,773	7,660
In-Licensed Rights [Member]
Finite Lived Intangible Assets [Line Items]
Total intangible assets	5,626	6,491
Software Licenses [Member]
Finite Lived Intangible Assets [Line Items]
Total intangible assets	$ 175	$ 204