Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net loss	$ (8,772,000)	$ (7,790,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	753,000	92,000
Depreciation expense	21,000	14,000
Changes in assets and liabilities:
Prepaid expenses and other current assets	(2,400,000)	200,000
Operating lease right-of-use assets	440,000	436,000
Accounts payable	138,000	839,000
Accrued expenses and other current liabilities	(1,237,000)	618,000
Operating lease liabilities	(438,000)	(418,000)
Net cash used in operating activities	(11,495,000)	(6,009,000)
Cash flows from investing activities:
Purchases of property and equipment	(85,000)	(121,000)
Net cash used in investing activities	(85,000)	(121,000)
Cash flows from financing activities:
Payment of offering costs	(1,708,000)
Proceeds from initial public offering, net of underwriting discount	59,892,000
Proceeds from exercise of stock options		87,000
Net cash provided by financing activities	88,371,000	87,000
Net increase (decrease) in cash and cash equivalents	76,791,000	(6,043,000)
Cash and cash equivalents and restricted cash, beginning of period	10,137,000	24,217,000
Cash and cash equivalents and restricted cash, end of period	86,928,000	18,174,000
Supplemental disclosure of non-cash financing and investing activities:
Property and equipment purchases included in accounts payable	30,000
Conversion of redeemable convertible preferred stock	160,227,000
Accretion of redeemable convertible preferred stock to redemption value	115,000	155,000
Right-of-use asset obtained in exchange of operating lease obligation	13,000	4,045,000
Deferred offering costs included in accounts payable and accrued expense	630,000	$ 7,000
Series C
Cash flows from financing activities:
Proceeds from the sale of Series C redeemable convertible preferred stock	30,392,000
Payment of offering costs	(205,000)
Supplemental disclosure of non-cash financing and investing activities:
Allocation of Series C redeemable convertible preferred stock to common stock warrant	740,000
Series C redeemable convertible preferred stock issuance costs included in accounts payable and accrued expense	$ 1,000