Goodwill, In-Process Research and Development and Intellectual Property - Carrying Value of Company's IPR&D Assets and Change in Balance (Detail) - In-Process Research and Development [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Beginning balance		$ 15,920
Additions	$ 10,633
Foreign currency translation impact	114	1,993
Transfer to developed technology		$ (17,913)
Ending balance	$ 10,747