Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($)	Total	Initial Public Offering	Common Stock	Common Stock Initial Public Offering	Additional Paid-in Capital	Additional Paid-in Capital Initial Public Offering	Accumulated Deficit	Accumulated Deficit Initial Public Offering	Convertible Preferred Stock
Beginning balance at Jan. 18, 2018	$ 0		$ 0		$ 0		$ 0
Beginning balance, shares at Jan. 18, 2018									0
Beginning balance at Jan. 18, 2018									$ 0
Beginning balance, shares at Jan. 18, 2018			0
Issuance of common stock	11,000		$ 1,000		10,000		0
Issuance of common stock, shares			611,226
Issuance of convertible preferred stock, net of issuance costs	0		$ 0		0		0		$ 22,973,000
Issuance of convertible preferred stock, net of issuance costs, shares			0						23,900,000
Conversion of convertible note into preferred stock	0		$ 0		0		0		$ 100,000
Conversion of convertible note into preferred stock, shares			0						100,000
Share-based compensation	108,000		$ 0		108,000		0
Net loss and comprehensive loss	(16,176,000)		0		0		(16,176,000)
Ending balance at Dec. 31, 2018	$ (16,057,000)		$ 1,000		118,000		(16,176,000)
Ending balance, shares at Dec. 31, 2018	24,000,000								24,000,000
Ending balance at Dec. 31, 2018	$ 23,073,000								$ 23,073,000
Ending balance, shares at Dec. 31, 2018			611,226
Issuance of common stock		$ 87,691,000		$ 6,000		$ 87,685,000		$ 0
Issuance of common stock, shares				6,100,390
Issuance of convertible preferred stock, net of issuance costs	0		$ 0		0		0		$ 26,673,000
Issuance of convertible preferred stock, net of issuance costs, shares									20,000,000
Conversion of convertible preferred stock into common stock upon completion of initial public offering	49,746,000		$ 7,000		49,739,000		0
Temporary Equity, Conversion of convertible preferred stock into common stock upon completion of initial public offering, shares									(44,000,000)
Temporary Equity, Conversion of convertible preferred stock into common stock upon completion of initial public offering									$ (49,746,000)
Conversion of convertible preferred stock into common stock upon completion of initial public offering, shares			7,077,366
Share-based compensation	389,000		$ 0		389,000		0
Capital contribution related to extinguishment of preferred stock liability	25,595,000		0		25,595,000		0		0
Net loss and comprehensive loss	(57,420,000)		0		0		(57,420,000)		$ 0
Ending balance at Dec. 31, 2019	$ 89,944,000		$ 14,000		$ 163,526,000		$ (73,596,000)
Ending balance, shares at Dec. 31, 2019	0								0
Ending balance at Dec. 31, 2019									$ 0
Ending balance, shares at Dec. 31, 2019			13,788,982