Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024	Dec. 31, 2023
Cash flows from operating activities:
Net loss			$ (15,984)	$ (70,583)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation			1,739	3,286
Depreciation expense	$ 200	$ 200	255	281
Impairment of property and equipment	0	1,883	0	1,883	$ 1,900	$ 1,600
Write-off of deferred financing costs				140
Impairment of right-of-use assets	0	22,836	0	22,836	22,800
Gain on sale of property and equipment			(8)
Net amortization of premium on short-term investments				(1,608)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets			1,169	131
Operating lease right-of-use assets			1,566	227
Other assets				1,111
Accounts payable			(499)	1,818
Accrued expenses and other current liabilities			(541)	(2,502)
Restructuring liability			(861)	3,127
Operating lease liabilities			(1,902)	(1,453)
Deferred revenue			(366)	(1,130)
Net cash used in operating activities			(15,432)	(42,436)
Cash flows from investing activities:
Purchases of property and equipment			(20)	(2,345)
Proceeds from the sale of property and equipment			18
Purchases of short-term investments				(35,141)
Maturity of short-term investments				81,519
Net cash (used in) provided by investing activities			(2)	44,033
Cash flows from financing activities:
Proceeds from sale of common stock, warrants and pre-funded warrants			4,999	8,819
Payment of deferred offering costs			(358)	(267)
Proceeds from exercise of stock options				3
Net cash provided by financing activities			4,641	8,555
Net decrease in cash, cash equivalents and restricted cash			(10,793)	10,152
Cash, cash equivalents and restricted cash, beginning of period			42,570	23,745	23,745
Cash, cash equivalents and restricted cash, end of period	$ 31,777	$ 33,897	31,777	33,897	$ 42,570	$ 23,745
Supplemental disclosure of non-cash financing and investing activities:
Issuance costs in accrued expenses			$ 368
Property and equipment purchases included in accounts payable				64
Right of Use Asset in Exchange for Lease Liability				13,667
Prepaid expenses for right-of-use asset included in operating lease liabilities				440
Deferred offering costs included in accounts payable and accrued expenses				$ 23