Goodwill, In-Process Research and Development and Intellectual Property - Summary of Gross Intellectual Property, Accumulated Amortization, and Net Intellectual Property (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Developed Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 66,413	$ 66,413
Accumulated Amortization	(25,273)	(19,724)
Foreign currency translation impact	4,382	5,529
Net Carrying Amount	45,522	52,218
Technology and Patents Purchased [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	400	400
Accumulated Amortization	(51)	(30)
Foreign currency translation impact	38	50
Net Carrying Amount	387	420
Intellectual Property [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	66,813	66,813
Accumulated Amortization	(25,324)	(19,754)
Foreign currency translation impact	4,420	5,579
Net Carrying Amount	$ 45,909	$ 52,638