Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Operating activities:
Net loss	$ (8,482)	$ (9,207)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization (accretion)	(30)	1,363
Right-of-use asset accretion	0	(67)
Stock-based compensation	893	1,932
Gain on sale of fixed assets	(219)	0
Prepaid rent	1,112	0
Realized investment losses	0	(53)
Other non-cash transactions	21	(110)
Changes in operating assets and liabilities	(1,771)	(18,285)
Net cash used in operating activities	(8,476)	(24,427)
Investing activities:
Purchases of property and equipment	0	(115)
Proceeds from maturity of investments	9,000	18,895
Proceeds on sale of fixed assets	2,176	0
Purchases of investments	0	(8,243)
Net cash provided by investing activities	11,176	10,537
Financing activities:
Proceeds from employee stock purchase plan	0	52
Proceeds from issuance of common stock resulting from ATM sales, net of $0.7 million in transaction costs, respectively	0	19,729
Net cash provided by financing activities	0	19,781
Effect of exchange rate change on cash and cash equivalents	(365)	412
Net increase in cash and cash equivalents	2,335	6,303
Cash and cash equivalents at beginning of period	17,396	38,635
Cash and cash equivalents at end of period	19,731	44,938
Supplemental cash flow disclosures:
Net unrealized gain (loss) on investments	(1)	72
Property and equipment included in accounts payable	$ 0	$ 74