Fair Value Measurements - Additional Information (Detail) $ in Millions	Jun. 30, 2019 USD ($)
Fair Value Disclosures [Abstract]
Fair value of convertible notes	$ 249.6

Fair value portion of borrowing which can be exchanged for a specified number of another security at the option of the issuer or the holder, for example, but not limited to, the entity's common stock.

No definition available.

Name:	us-gaap_ConvertibleDebtFairValueDisclosures
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant