Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net loss	$ (12,760,000)	$ (24,522,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	2,491,000	4,410,000
Non-cash interest expense	4,741,000	1,417,000
Amortization of debt issuance costs and debt discount	2,305,000	1,656,000
Depreciation and amortization expense	273,000	304,000
Fair value adjustment related to derivative and warrant liability	184,000	(1,998,000)
Change in estimated deferred offering costs		116,000
Loss on sublease and disposal of property and equipment	251,000
Consulting fees paid in common stock	202,000
Change in assets and liabilities:
Accounts and other receivables	(714,000)	(1,725,000)
Prepaid expenses and other assets	160,000	544,000
Operating lease right-of-use assets	128,000	(1,537,000)
Accounts payable and accrued expenses	931,000	(3,789,000)
Operating lease liabilities	(271,000)	2,185,000
Other liabilities	140,000	(798,000)
Net cash used in operating activities	(1,939,000)	(23,737,000)
Cash flows from investing activities:
Purchases of property and equipment	(33,000)	(26,000)
Maturities of marketable securities		3,260,000
Net cash (used in) provided by investing activities	(33,000)	3,234,000
Cash flows from financing activities:
Proceeds from equity line of credit	2,303,000	5,446,000
Proceeds from Payment Protection Program loan	781,000
Payment of offering costs	(84,000)
Repayment of principal on finance lease liabilities	(227,000)	(207,000)
Payment of debt issuance costs	(34,000)	(300,000)
Net cash provided by financing activities	2,739,000	4,939,000
Net increase (decrease) in cash, cash equivalents and restricted cash	767,000	(15,564,000)
Cash, cash equivalents and restricted cash, beginning of year	3,555,000	19,119,000
Cash, cash equivalents and restricted cash, end of year	4,322,000	3,555,000
Supplemental cash flow information:
Cash paid for interest	78,000	5,362,000
Commitment shares issued in connection with equity line of credit included in deferred offering costs	121,000	300,000
Deferred offering costs included in accounts payable and accrued expenses	817,000
Cash paid in lieu of fractional shares in connection with 16-for-1 reverse stock split included in accounts payable and accrued expenses	23,000
Property and equipment financed under a lease agreement	17,000
Property and equipment included in accounts payable and accrued expenses	4,000	4,000
The 2021 Notes Converted to Preferred Stock [Member]
Supplemental cash flow information:
Notes principal converted		1,537,000
The 2021 Notes Converted to Common Stock [Member]
Supplemental cash flow information:
Notes principal converted		1,463,000
The 2019 Notes Converted to Common Stock [Member]
Supplemental cash flow information:
Notes principal converted	$ 15,863,000	$ 1,200,000