Bristol-Meyers Squibb License Agreement - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended
	Apr. 20, 2016	Mar. 31, 2022	Dec. 31, 2020	Dec. 31, 2021
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate fair value of shares issued		$ 41		$ 35
Common Stock [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Sale of common stock		5,841,786
BMS Transaction [Member] | Licensing Agreements [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment	$ 2,000
BMS Transaction [Member] | Common Stock [Member] | BMS Purchase Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Sale of common stock	157,587
Aggregate fair value of shares issued	$ 3,200
BMS Transaction [Member] | Development and Regulatory Milestones [Member] | Licensing Agreements [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payment obligations	61,000
BMS Transaction [Member] | Commercial Sales [Member] | Maximum [Member] | Licensing Agreements [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payment obligations	$ 128,000
BMS Transaction [Member] | Development Phase 2 [Member] | Licensing Agreements [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payment obligations			$ 3,000
BMS Transaction [Member] | Development Phase 3 [Member] | Licensing Agreements [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payment obligations		$ 5,000