Company Organization and Nature of Business - Additional Information (Details) $ / shares in Units, $ in Thousands			1 Months Ended	3 Months Ended	9 Months Ended
	Jun. 15, 2020 shares	Jun. 05, 2020	Jun. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2020 $ / shares shares	Sep. 30, 2020 USD ($) shares	Jun. 17, 2020 shares	Dec. 31, 2019 shares
Schedule Of Organization Consolidation And Presentation Of Financial Statements [Line Items]
Reverse stock split		one-for-1.6870
Reverse stock split, conversion ratio		0.593
Net proceeds from initial public offering | $			$ 264,000
Underwriting discounts and commissions | $			20,100
Offering expenses | $			$ 3,400		$ 3,368
Redeemable convertible preferred stock, shares outstanding							20,390,095
Redeemable Convertible Preferred Stock
Schedule Of Organization Consolidation And Presentation Of Financial Statements [Line Items]
Conversion of preferred stock (in shares)			28,610,337
Redeemable convertible preferred stock, shares outstanding					0	0
Common Stock
Schedule Of Organization Consolidation And Presentation Of Financial Statements [Line Items]
Shares issued and sold				17,968,750
Conversion of preferred stock (in shares)	28,610,337			28,610,337
Initial Public Offering
Schedule Of Organization Consolidation And Presentation Of Financial Statements [Line Items]
Shares issued and sold			17,968,750
Underwriters’ option to purchase additional shares			2,343,750
Public offering price per share | $ / shares			$ 16.00	$ 16.00
Pneumococcal Conjugate Vaccine
Schedule Of Organization Consolidation And Presentation Of Financial Statements [Line Items]
Global target revenue | $					$ 7,000,000