Contingent Consideration - Additional Information (Detail) - USD ($)	Jul. 12, 2019	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Estimated future contingent consideration		$ 6,950,000	$ 5,390,000	$ 25,070,000	$ 2,750,000
Spitfire Pharma, Inc. [Member]
Business Acquisition [Line Items]
Agreement date	Jul. 08, 2019
Unregistered shares of common stock	1,887,250
Up-front consideration	$ 5,000,000.0
Spitfire Pharma, Inc. [Member] | Investigational New Drug Application Milestone [Member]
Business Acquisition [Line Items]
Estimated future contingent consideration	$ 5,000,000.0
Estimated future contingent consideration term	60 days
Number of consecutive trading days	20 days
Consideration amount	$ 2.95
Spitfire Pharma, Inc. [Member] | Investigational New Drug Application and Regulatory Milestones [Member]
Business Acquisition [Line Items]
Estimated future contingent consideration	$ 3,000,000.0
Estimated future contingent consideration term	60 days
Number of consecutive trading days	20 days
Consideration amount	$ 3.54
Spitfire Pharma, Inc. [Member] | Sales Milestones [Member]
Business Acquisition [Line Items]
Estimated future contingent consideration	$ 80,000,000.0
License agreement term	10 years
Spitfire Pharma, Inc. [Member] | Regulatory Milestones [Member]
Business Acquisition [Line Items]
Upfront consideration release at 3 months	50.00%
Upfront consideration release at 9 months	50.00%
Spitfire Pharma, Inc. [Member] | Common Stock [Member] | Maximum [Member]
Business Acquisition [Line Items]
Estimated future contingent consideration	$ 88,000,000.0