CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities:
Net loss	$ (76,404)	$ (88,222)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,900	1,847
Non-cash interest expense	157	223
Stock-based compensation expense	7,382	8,424
Loss on disposal of property and equipment	3	1
Changes in operating assets and liabilities:
Prepaid and other assets	688	344
Operating lease right-of-use asset	460	391
Accounts payable	(2,063)	485
Accrued expenses and other liabilities	175	1,585
Operating lease liability	(918)	(801)
Net cash used in operating activities	(68,620)	(75,723)
Cash flows from investing activities:
Purchases of property and equipment	(486)	(1,867)
Net cash used in investing activities	(486)	(1,867)
Cash flows from financing activities:
Repayments of debt principal	(6,667)
Payments of finance lease	(85)	(85)
Proceeds from issuance of common stock under employee stock purchase plan	194
Proceeds from exercise of stock options	8	16
Net cash used in financing activities	(6,550)	(69)
Decrease in cash, cash equivalents and restricted cash	(75,656)	(77,659)
Cash, cash equivalents and restricted cash, beginning of period	121,947	199,606
Cash, cash equivalents and restricted cash, end of period	46,291	121,947
Supplemental cash flow disclosure:
Cash paid for interest	573	555
Supplemental disclosure of non-cash activities:
Capital expenditures included in accounts payable or accrued expenses		19
Reconciliation to amounts within the consolidated balance sheets:
Cash and cash equivalents	44,704	120,385
Restricted cash	1,587	1,562
Cash, cash equivalents and restricted cash, end of period	$ 46,291	$ 121,947