Subsequent Events - Additional Information (Detail) - Subsequent Events [Member] - Lease Agreements [Member] $ in Millions	May 03, 2018 USD ($)	Apr. 27, 2018 USD ($) ft²
Myonexus Therapeutics, Inc. [Member]
Subsequent Event [Line Items]
Up-front payment	$ 60.0
Development milestone payments	$ 45.0
Seventh Amendment [Member]
Subsequent Event [Line Items]
Extended original term of lease		Sep. 30, 2025
Total rental space | ft²		63,698
Incremental rent expense		$ 54.4