U.S. Government Contracts and Grants - Additional Information (Detail) - USD ($)			1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 01, 2021	Jul. 31, 2016	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues				$ 137,623	$ 721,636	$ 975,139	$ 2,934,330
BARDA Contract [Member]
Duration of contract	3 years	5 years
Amount used to fund clinical development		$ 133,700,000
BARDA Contract [Member] | Minimum [Member]
Additional funding for development and manufacturing activities	$ 1,100,000
BARDA Contract [Member] | Maximum [Member]
Additional funding for development and manufacturing activities	$ 34,400,000
Collaborative Arrangement [Member]
Revenues			$ 4,700,000
Grant [Member] | BARDA Contract [Member]
Revenues				$ 100,000	$ 500,000	300,000	$ 2,100,000
Grant [Member] | Collaborative Arrangement [Member]
Revenues						$ 500,000
Investment Performance [Member] | BARDA Contract [Member]
Revenues		$ 27,800,000