License Revenue - Additional Information (Detail1) - January 2018 Amendment Agreement [Member] - USD ($) $ in Millions	1 Months Ended	6 Months Ended
	May 31, 2018	Jun. 30, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2018-01-01
License Revenue [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period		1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: (nil)
License Revenue [Line Items]
Sales-based milestone payment exclude transaction price		$ 80.0
Payments due from related party		$ 30.0
Consideration payment due period one		2019-01
Consideration payment due period two		2020-01
Share-based Milestone [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: (nil)
License Revenue [Line Items]
Increase in transaction price of license	$ 40.0