Funding Arrangement - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended		9 Months Ended
	Apr. 30, 2021	Jul. 31, 2019	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Aug. 04, 2021	Dec. 31, 2020	Jul. 31, 2020
Funding Arrangement [Line Items]
Grant income			$ 299,000	$ 787,000	$ 677,000	$ 2,152,000
Cost Reimbursement Sub-Award Agreement
Funding Arrangement [Line Items]
Funding period of award to develop universal vaccine to prevent infections caused by Group A Strep bacteria		4 years
Potential funding amount of award to develop vaccine to prevent shingella infections	$ 500,000
Grant income			300,000	$ 800,000	700,000	$ 2,200,000
Cost Reimbursement Sub-Award Agreement | Maximum
Funding Arrangement [Line Items]
Initial funding committed by award		$ 1,600,000
Total funding committed by award, available upon achievement of development milestones		$ 15,100,000
Potential funding period of award to develop vaccine to prevent shingella infections	5 years
CARB-X Agreement
Funding Arrangement [Line Items]
Additional funding committed by award							$ 3,200,000
Grant receivable on unreimbursed, eligible costs incurred			$ 700,000		$ 700,000			$ 300,000
CARB-X Agreement | Maximum
Funding Arrangement [Line Items]
Initial funding committed by award									$ 2,700,000
Additional funding committed by award							3,200,000
Potential funding committed by award							$ 29,700,000
CARB-X Agreement | Minimum
Funding Arrangement [Line Items]
Initial funding committed by award									$ 1,600,000