Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net loss	$ (9,074)	$ (11,830)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	46	57
Amortization of operating lease right-of-use assets	283	265
Warrant modification expense		666
Share-based compensation expense	215	268
Non-cash investment (income) expense, net		1
Changes in operating assets and liabilities:
Prepaid expenses	14	267
Other assets		(123)
Accounts payable	(461)	127
Operating lease liability	(294)	(144)
Accrued expenses and other liabilities	(263)	132
Net cash used in operating activities	(9,534)	(10,314)
Cash flows from investing activities:
Purchases of property and equipment	(41)	(12)
Net cash used in investing activities	(41)	(12)
Cash flows from financing activities:
Proceeds from issuance of stock under ESPP		1
Proceeds from exercise of warrants	343
Repayment of loan payable		(100)
Proceeds from issuance of common stock and warrants, net of commissions and issuance costs	22,119	367
Net cash provided by financing activities	22,462	268
Increase / (decrease) in cash and cash equivalents and restricted cash	12,887	(10,058)
Cash, cash equivalents and restricted cash at beginning of period	6,716	16,774
Cash, cash equivalents and restricted cash at end of period	19,603	6,716
Supplemental disclosure of cash flow information and non-cash investing and financing activities:
Fair value of warrants issued in connection with financing activities	$ 15,194	59
Cash paid for interest		1
Right-of-use assets and lease liability recorded upon adoption of ASC 842		$ 1,475