Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities
Net loss	$ (36,838,000)	$ (28,034,000)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation expense	37,000	34,000
Amortization expense - right-of-use leased assets - operating	431,000	404,000
Accretion on short-term investments	(244,000)	124,000
Stock-based compensation	2,838,000	2,366,000
Non-cash interest expense	884,000	554,000
Fair value adjustment to derivative liability	(1,335,000)
Changes in operating assets and liabilities
Inventory	(1,230,000)
Prepaid expenses and other assets	(887,000)	(234,000)
Accounts payable, accrued expenses and other liabilities	1,767,000	(2,365,000)
Net cash flows used in operating activities	(34,577,000)	(27,151,000)
Cash flows from investing activities
Purchases of property and equipment	(21,000)	(9,000)
Maturities of short-term investments	21,700,000	41,150,000
Purchases of short-term investments	(67,538,000)	(9,011,000)
Net cash flows provided by (used in) investing activities	(45,859,000)	32,130,000
Cash flows from financing activities
Proceeds from common stock offering, net of underwriter discounts and offering costs	46,645,000
Proceeds from at-the-market offering, net	1,120,000
Proceeds from the exercise of stock options	44,000	9,000
Proceeds from employee stock purchase plan	173,000	42,000
Proceeds from term loan	47,301,000
Principal payments on term loan	(17,500,000)	(2,500,000)
Payment Of Term Loan Final Fee	(500,000)
Settlement of restricted stock units for tax withholding obligations	(54,000)	(81,000)
Net cash flows (used in) provided by financing activities	77,229,000	(2,530,000)
Net increase (decrease) in cash	(3,207,000)	2,449,000
Cash, cash equivalents and restricted cash, beginning of year	74,450,000	72,001,000
Cash, cash equivalents and restricted cash, end of year	71,243,000	74,450,000
Supplemental cash flow information
Interest paid	2,555,000	2,043,000
Taxes paid	190,000	$ 206,000
Supplemental disclosure of non-cash activities
Transfer of issuance costs from other noncurrent assets to equity	$ 6,000