Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (25,504)	$ (30,094)
Adjustments to reconcile net loss to net cash used in operating activities
Stock-based compensation	2,292	4,621
Impairment charge on investment in equity securities	1,710	2,990
Depreciation	17	23
Loss on disposal of assets	7	0
Changes in operating assets and liabilities:
Prepaid materials	(611)	2,544
Prepaid expenses and other current assets	997	1,004
Other assets	331	(1,697)
Accounts payable	(127)	(2,159)
Accrued expenses	(54)	(86)
Payroll liabilities	208	129
Other current liabilities	(296)	1,784
Net cash used in operating activities	(21,030)	(20,941)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchase of property and equipment	(19)	(14)
Net cash used in investing activities	(19)	(14)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from exercise of warrants	3,673	0
Common stock repurchased	0	(1,475)
Net cash provided by (used in) financing activities	3,673	(1,475)
NET DECREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(17,376)	(22,430)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, BEGINNING BALANCE	88,570	111,000
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, ENDING BALANCE	71,194	88,570
RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH
Cash and cash equivalents	71,084	88,460
Restricted cash	110	110
Total cash, cash equivalents and restricted cash	71,194	88,570
Noncash Investing and Financing Items [Abstract]
Common stock issued upon cashless exercise of stock options	$ 273	$ 0