Government Contracts - Additional Information (Detail)		1 Months Ended		3 Months Ended		9 Months Ended
	Jul. 01, 2019 USD ($)	May 31, 2021 USD ($) Option	Jul. 31, 2018 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) Option	Sep. 30, 2022 USD ($)	Jan. 19, 2022 USD ($)	Jan. 31, 2020 USD ($)	May 31, 2019 USD ($)
Government Contracts [Line Items]
Grant revenue				$ 25,473,000	$ 2,006,000	$ 30,259,000	$ 6,068,000
BARDA and DTRA [Member]
Government Contracts [Line Items]
Maximum potential funding from government contract				69,700,000		69,700,000
Potential grant amount exercised				12,700,000		12,700,000
Grant [Member] | DoD, CDMRP and JWMRP [Member]
Government Contracts [Line Items]
Grant revenue				0	100,000	0	1,000,000
SPR206 [Member] | DoD, CDMRP and JWMRP [Member]
Government Contracts [Line Items]
Award received for clinical development	$ 5,900,000
Non-dilutive funding period	4 years
BARDA [Member]
Government Contracts [Line Items]
Potential contract amount awarded			$ 44,200,000					$ 59,700,000
Potential amount additional funding awarded								12,900,000
Overall potential award increased								$ 46,900,000
Award received for clinical development					12,900,000		12,900,000
BARDA [Member] | Base Period Contracts [Member]
Government Contracts [Line Items]
Potential amount initial funding awarded			$ 15,700,000
Potential amount additional funding awarded										$ 2,500,000
Overall potential award increased										46,800,000
Contract term			3 years
BARDA [Member] | Base Period Contracts [Member] | Maximum [Member]
Government Contracts [Line Items]
Potential amount initial funding awarded										18,200,000
BARDA [Member] | Base Period Contracts [Member] | Minimum [Member]
Government Contracts [Line Items]
Potential amount initial funding awarded										$ 15,700,000
BARDA [Member] | Grant [Member]
Government Contracts [Line Items]
Grant revenue				1,600,000	500,000	3,100,000	1,900,000
BARDA [Member] | First Option [Member]
Government Contracts [Line Items]
Potential amount additional funding awarded									$ 15,900,000
Potential amount increase in committed funding									$ 34,000,000
BARDA [Member] | Second Option [member]
Government Contracts [Line Items]
Potential grant amount awarded				12,700,000		12,700,000
DTRA [Member] | Maximum [Member]
Government Contracts [Line Items]
Potential amount additional funding awarded				10,000,000		10,000,000
Niaid [Member] | SPR206 [Member]
Government Contracts [Line Items]
Contract term		5 years
Potential amount increase in committed funding				2,200,000		2,200,000
Grant revenue				500,000	$ 300,000	2,300,000	$ 1,000,000
Award received for clinical development		$ 23,500,000
Number of option period for funding from government contract | Option		6
Niaid [Member] | First Option [Member] | SPR206 [Member]
Government Contracts [Line Items]
Potential amount increase in committed funding				4,000,000		$ 4,000,000
Number of option period for funding from government contract | Option						1
Niaid [Member] | Third Option [Member] | SPR206 [Member]
Government Contracts [Line Items]
Potential amount increase in committed funding				$ 800,000		$ 800,000
Number of option period for funding from government contract | Option						3