Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Cash flows from operating activities:
Net loss	$ (43,205)	$ (46,507)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	521	508
Stock-based compensation	6,519	8,283
Amortization of premiums and discounts on marketable securities	(2,902)	(3,532)
Amortization of debt discount and issuance costs and other non-cash interest	129	118
Impairment loss of right-of-use asset	1,549	0	$ 2,700
Changes in operating assets and liabilities
Prepaid expenses and other current assets	2,143	2,246
Other assets	(927)	(5,888)
Accounts payable, accrued and other current liabilities	(3,106)	2,453
Operating lease asset and liabilities	(614)	(141)
Net cash used in operating activities	(39,893)	(42,460)
Cash flows from investing activities:
Purchases of property and equipment	0	(1,673)
Purchases of marketable securities	(52,126)	(95,233)
Maturities of marketable securities	84,750	126,500
Net cash provided by investing activities	32,624	29,594
Cash flows from financing activities:
Proceeds from issuance of common stock under employee stock incentive plans	56	536
Net cash provided by financing activities	56	536
Effect of exchange rate changes on cash and cash equivalents	(4)	(17)
Net decrease in cash and cash equivalents	(7,217)	(12,347)
Cash and cash equivalents at the beginning of period	35,493	40,456	40,456
Cash and cash equivalents at the end of period	28,276	28,109	$ 35,493
Supplemental disclosures of noncash investing and financing information:
Purchases of property and equipment in accounts payable	0	117
Par value of common stock upon cashless exercise of prefunded warrants	0	4
Supplemental disclosures
Cash paid for interest	$ 672	$ 637