Goodwill, In-Process Research and Development and Intellectual Property - Summary of Estimated Future Amortization Expense of Intangible Assets (Detail) - Intellectual Property [Member] - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
2019	$ 10,540
2020	10,538
2021	10,538
2022	7,915
2023	42
Thereafter	143
Total	$ 39,716	$ 52,638

Goodwill, In-Process Research and Development and Intellectual Property - Summary of Estimated Future Amortization Expense of Intangible Assets (Detail) - Intellectual Property [Member] - USD ($)
$ in Thousands

Dec. 31, 2018

Dec. 31, 2017

Finite-Lived Intangible Assets [Line Items]

$ 10,540

10,538

10,538

7,915

143

$ 39,716

$ 52,638