CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities
Net loss	$ (11,924)	$ (17,326)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	179	174
Amortization (accretion) on marketable securities	0	(143)
Non-cash interest expense	29	24
Non-cash lease expense	140	131
Non-cash (income) expense from collaborative arrangements, net	913	1,008
Stock-based compensation expense	1,761	2,689
Other	9	352
Changes in assets and liabilities:
Prepaid expenses and other current assets	(117)	(60)
Accounts payable and accrued expenses	(1,446)	(4,964)
Lease obligations	(139)	(125)
Net cash used in operating activities	(10,595)	(18,240)
Cash flows from investing activities
Purchases of marketable securities	0	(3,947)
Proceeds from the maturities of marketable securities	0	9,000
Purchases of property and equipment	(2,352)	(1,612)
Net cash (used in) provided by investing activities	(2,352)	3,441
Cash flows from financing activities
Proceeds (payments) from issuance of common stock, net	(145)	5,731
Payment of equity issuance costs	0	(173)
Proceeds from issuance of debt	0	(62)
Net cash (used in) provided by financing activities	(145)	5,496
Effect of changes in exchange rate on cash and cash equivalents	5	(1)
Net (decrease) in cash and cash equivalents	(13,087)	(9,304)
Cash and cash equivalents at beginning of period	39,462	77,563
Cash and cash equivalents at end of period	26,375	68,259
Supplemental disclosure of non-cash investing and financing transactions:
Purchases of property and equipment	$ 371	$ 1,119