Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net loss	$ (4,232,000)	$ (3,589,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	134,000	48,000
Depreciation expense	8,000	8,000
Changes in assets and liabilities:
Prepaid expenses and other current assets	18,000	35,000
Operating lease right-of-use asset	219,000	226,000
Accounts payable	432,000	(46,000)
Accrued expenses and other current liabilities	(381,000)	527,000
Operating lease liability	(215,000)	(214,000)
Net cash used in operating activities	(4,017,000)	(3,005,000)
Cash flows from investing activities:
Purchases of property and equipment	(8,000)	(52,000)
Net cash used in investing activities	(8,000)	(52,000)
Cash flows from financing activities:
Payment of offering costs	(773,000)
Net cash provided by financing activities	29,464,000
Net increase (decrease) in cash and cash equivalents	25,439,000	(3,057,000)
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	35,576,000	21,160,000
Supplemental disclosure of non-cash financing and investing activities:
Property and equipment purchases included in accounts payable	49,000
Accretion of redeemable convertible preferred stock to redemption value	85,000	77,000
Right-of-use asset obtained in exchange of operating lease obligation		$ 4,045,000
Deferred offering costs included in accounts payable and accrued expense	702,000
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	(155,000)
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	$ 51,000