Funding Arrangement - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended		9 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Funding Arrangement [Line Items]
Grant income			$ 787,000	$ 54,000	$ 2,152,000	$ 54,000
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
Percentage of reimbursable expenses		50.00%
Grant income			800,000	$ 100,000	2,200,000	$ 100,000
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
CARB-X Agreement
Funding Arrangement [Line Items]
Funding period of award to develop universal vaccine to prevent infections caused by Group A Strep bacteria	4 years
Grant receivable on unreimbursed, eligible costs incurred			$ 800,000		$ 800,000		$ 200,000
CARB-X Agreement | Maximum
Funding Arrangement [Line Items]
Percentage of reimbursable expenses	90.00%
Initial funding committed by award	$ 2,700,000
Total funding committed by award, available upon achievement of development milestones	$ 15,100,000
CARB-X Agreement | Minimum
Funding Arrangement [Line Items]
Percentage of reimbursable expenses	50.00%
Initial funding committed by award	$ 1,600,000