STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities:
Net loss	$ (35,140)	$ (37,730)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	2,315	2,759
Property and equipment and right-of-use assets impairment	4,803	0
Amortization of financing costs	1,339	981
Stock-based compensation	2,800	3,528
Decrease in the carrying amount of right-of-use assets	286	486
Gain on lease modification and termination	(298)	(133)
Loss on sale of equipment, net	7	7
(Increase) decrease in:
Receivables	3	1,107
Prepaid expenses and other current assets	(1,399)	867
Deposits	42	0
Other non-current assets	500	131
Increase (decrease) in:
Accounts payable	(773)	(25)
Accrued expenses	(3,989)	(668)
Lease liabilities	(610)	(570)
Other non-current liabilities	(28)	28
Net cash used in operating activities	(30,142)	(29,232)
Cash flows from investing activities:
Purchases of property and equipment	(197)	(216)
Proceeds from the disposal of property and equipment	1,543	23
Net cash provided by (used in) investing activities	1,346	(193)
Cash flows from financing activities:
Proceeds from the issuance of common stock	92	14,724
Proceeds from the exercise of stock options	0	21
Repurchase of common stock	0	(45)
Repayment of long-term debt	(18,105)	(8,333)
Debt extinguishment costs	(125)	0
Net cash provided by (used in) financing activities	(18,138)	6,367
Net decrease in cash, cash equivalents and restricted cash	(46,934)	(23,058)
Cash, cash equivalents and restricted cash, beginning of period	52,996	76,054
Cash and cash equivalents, end of period	6,062	52,996
Supplementary disclosure of cash flow information:
Cash paid for interest	2,063	2,171
Reduction in right-of-use assets for modification and termination	1,839	1,790
Amounts included in accrued expenses and accounts payable related to property and equipment	$ 0	$ 91