Subsequent Events - Additional Information (Detail) - USD ($) $ in Millions		9 Months Ended
	Oct. 26, 2015	Sep. 30, 2015
Subsequent Event [Line Items]
Potential milestone payment receivable upon regulatory approval		$ 50
Deferred revenue recognized during the period		$ 6
Subsequent Event [Member]
Subsequent Event [Line Items]
Potential milestone payment receivable upon regulatory approval	$ 50