CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Cash flows from operating activities:
Net loss	$ (82,037)	$ (64,763)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	6,148	4,092
Depreciation and amortization expense	357	389
Non-cash lease expense	1,173	1,104
Accretion of debt discount	681	653
Change in fair value of warrant liability	(743)	0
Other	(46)	255
Changes in operating assets and liabilities:
Prepaid expenses, other current assets and research and development incentive receivable	459	158
Accounts payable	426	(481)
Accrued expenses and other long-term liabilities	5,651	1,305
Lease liabilities	(834)	(721)
Net cash used in operating activities	(68,765)	(58,009)
Cash flows from investing activities:
Payments to Acquire Marketable Securities	(11,025)	0
Sales and maturities of marketable securities	1,000	0
Acquisition of property and equipment	(25)	(69)
Net cash used in investing activities	(10,050)	(69)
Cash flows from financing activities:
Proceeds from Issuance of Common Stock	8,615	70
Employee taxes paid related to net share settlement of vested restricted stock units	0	(12)
Fees paid to amendment loan and security agreement and issuance costs related to the sale of warrants	(631)	(3,300)
Repayments of Secured Debt	(2,064)	(795)
Proceeds from borrowings under loan and security agreement	22,500	0
Proceeds from sale of common stock, warrants and pre-funded warrants, net of issuance costs	59,999	60,623
Net cash provided by financing activities	88,419	56,586
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(28)	(468)
Net increase (decrease) in cash, cash equivalents and restricted cash	9,576	(1,960)
Cash, cash equivalents and restricted cash at beginning of period	123,028	83,108
Cash, cash equivalents and restricted cash at end of period	132,604	81,148
Supplemental Cash Flow Elements [Abstract]
Debt Issuance Costs Incurred During Noncash or Partial Noncash Transaction	$ 0	$ 22