Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Cash flows from operating activities:
Net loss	$ (7,352)	$ (4,001)	$ (15,418)	$ (11,563)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation			618	1,210
Depreciation and amortization expense			5	8
Change in fair value of warrant derivative liability	288	(2,523)	(286)	(886)
Changes in operating assets and liabilities:
Accounts receivable, interest and other receivables			0	(4)
Prepaid expenses and other assets			662	(437)
Accounts payable			(14)	309
Accrued liabilities and other			10	(1,604)
Net cash used in operating activities			(14,423)	(12,967)
Cash flows from investing activities:
Purchases of property and equipment			(4)	(14)
Net cash used in investing activities			(4)	(14)
Effect of exchange rate changes on cash			0	(5)
Net change in cash, cash equivalents, and restricted cash			(14,427)	(12,986)
Cash, cash equivalents and restricted cash at beginning of period			21,837	47,657
Cash, cash equivalents and restricted cash at end of period	$ 7,410	$ 34,671	$ 7,410	$ 34,671