Intangible Assets - Additional Information (Detail) - IPR&D [Member] $ in Millions	3 Months Ended
Jun. 30, 2018 USD ($)
Acquired Intangible Assets [Line Items]
Abandonment loss in research and development operating expenses	$ 13.3
In-process research and development, production	$ 26.5

The amount of purchased research and development assets that are acquired in a business combination have no alternative future use and are therefore written off in the period of acquisition.

No definition available.

Name:	us-gaap_ResearchAndDevelopmentInProcess
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration