Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net loss	$ (35,258)	$ (8,931)
Adjustment to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	3,643	64
Change in fair value of derivative liabilities	6,393	15
Depreciation expense	47	44
Loss on disposal of property and equipment	38	0
Changes in current assets and liabilities:
Prepaid expenses and other current assets	(1,024)	12
Other non-current assets	(51)	(3)
Accounts payable	1,454	264
Amounts due to related party	(1,707)	(213)
Accrued expenses and other current liabilities	1,791	294
Net cash used in operating activities	(24,674)	(8,454)
Cash flows from investing activities:
Purchases of equipment	(21)	(76)
Net cash used in investing activities	(21)	(76)
Cash flows from financing activities:
Proceeds from issuance of convertible preferred stock, net	129,499	52,312
Payment of deferred offering costs	(1,743)	0
Net cash provided by financing activities	127,756	52,312
Net increase (decrease) in cash and cash equivalents	103,061	43,782
Cash, cash equivalents and restricted cash, beginning of year	51,660	7,878
Cash, cash equivalents and restricted cash, end of year	154,721	51,660
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents
Cash, cash equivalents and restricted cash, end of year	154,721	7,878
Supplemental disclosure of non-cash investing and financing activities:
Deferred offering and stock issuance costs included in accounts payable and accrued expenses and other current liabilities	656	0
Purchases of equipment included in accounts payable and accrued expenses	94	0
Series B
Supplemental disclosure of non-cash investing and financing activities:
Issuance of series B convertible preferred stock tranche right	0	4,000
Exercise of series B convertible preferred stock tranche right	$ 6,393	$ 0