Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2020
Cash flows from operating activities
Net loss	$ (31)	$ (41,693)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	0	3
Change in fair value of preferred stock tranche liability	0	17,030
Research and development license expense	0	6,000
Stock-based compensation	0	1,341
Changes in operating assets and liabilities:
Prepaid expenses	0	(604)
Accounts payable	0	5,403
Accrued expenses	31	1,579
Due to related party	0	60
Net cash used in operating activities	0	(10,881)
Cash flows from investing activities
Purchase of research and development license	0	(3,000)
Purchase of property and equipment	0	(31)
Net cash used in investing activities	0	(3,031)
Cash flows from financing activities
Proceeds from issuance of common stock in initial public offering, net of underwriting discounts and commission and other offering costs	0	167,162
Proceeds from notes payable to related party	0	1,673
Repayment of notes payable to related party	0	(1,673)
Net cash provided by financing activities	0	292,546
Net increase in cash and cash equivalents	0	278,634
Cash at the beginning of the period	0
Cash at the end of the period	0	278,634
Supplemental disclosure of cash flow information:
Cash paid for interest	0	28
Supplemental disclosure of noncash investing and financing activities:
Reclassification of preferred stock tranche liability upon share issuance	0	18,080
Allocation of preferred stock tranche liability	0	1,050
Conversion of Series A and Series B convertible preferred stock to common stock	0	142,240
Purchase of research and development license not yet paid	0	3,000
Series A Convertible Preferred Stock
Cash flows from financing activities
Proceeds from issuances of convertible preferred stock, net of issuance costs	0	29,569
Supplemental disclosure of noncash investing and financing activities:
Issuance costs for issuances of stock not yet paid	0	174
Series B Convertible Preferred Stock
Cash flows from financing activities
Proceeds from issuances of convertible preferred stock, net of issuance costs	0	95,815
Common Stock
Supplemental disclosure of noncash investing and financing activities:
Issuance costs for issuances of stock not yet paid	$ 0	$ 1,273