U.S. Government Contracts and Grants - Additional Information (Detail) - USD ($) $ in Thousands		1 Months Ended		3 Months Ended
	Jan. 01, 2021	Jun. 30, 2020	Jul. 31, 2016	Mar. 31, 2022	Mar. 31, 2021
Revenues				$ 32	$ 838
BARDA Contract [Member]
Duration of contract	3 years		5 years
Amount used to fund clinical development			$ 136,800
BARDA Contract [Member] | Minimum [Member]
Additional funding for development and manufacturing activities	$ 1,100
BARDA Contract [Member] | Maximum [Member]
Additional funding for development and manufacturing activities	$ 34,400
MTEC Collaborative Arrangement [Member]
Revenues		$ 4,700
Grant [Member] | BARDA Contract [Member]
Revenues					200
Grant [Member] | MTEC Collaborative Arrangement [Member]
Revenues				$ 0	$ 500
Investment Performance [Member] | BARDA Contract [Member]
Revenues			$ 30,900