Description of Business, Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands		12 Months Ended
	Jun. 07, 2019	Dec. 31, 2019 USD ($) segment shares	Dec. 31, 2018 USD ($) shares
Description Of Business Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Accumulated deficit		$ 65,572	$ 31,384
Cash and cash equivalents		20,051	20,645
Preferred stock warrant liability		1,300	674
Deferred grant revenue		$ 3,640
Grants receivable			$ 100
Number of operating segments | segment		1
Weighted-average shares subject to repurchase | shares		56,000	164,000
Merger Agreement
Description Of Business Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Reverse stock split of common stock	7
Merger Agreement | Combined organization's
Description Of Business Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Common stock and preferred stock exchange ratio	0.073386
Ownership percentage of stockholders upon closing of merger	77.50%