Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (6,229)	$ (8,011)	$ (22,340)	$ (19,469)
Adjustments to reconcile net loss to net cash used in operating activities
Compensation cost for stock options granted			4,102	5,243
Impairment charge on investment in equity securities	(0)	(0)	2,990	(0)
Depreciation and amortization			9	6
Disposal of assets			0	3
Changes in operating assets and liabilities:
Prepaid expenses			559	(2,619)
Research and development rebate receivable			715	462
Other current assets			719	992
Other assets			0	(597)
Accounts payable			(2,247)	(64)
Accrued expenses			202	(87)
Payroll liabilities			(81)	(113)
Other current liabilities			2	6
Net cash used in operating activities			(15,370)	(16,237)
CASH FLOWS FROM INVESTING ACTIVITIES
Deposit on investment in equity securities			0	(2,700)
Purchase of furniture and equipment			(14)	(19)
Net cash used in investing activities			(14)	(2,719)
CASH FLOWS FROM FINANCING ACTIVITIES
Common stock repurchased			(1,475)	0
Net cash used in financing activities			(1,475)	0
Effect of exchange rate change on cash			0	(54)
NET DECREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH			(16,859)	(19,010)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, BEGINNING BALANCE			111,000	136,487
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, ENDING BALANCE	94,141	117,477	94,141	117,477
SUPPLEMENTAL DISCLOSURES
Cash and cash equivalents	94,031	117,367	94,031	117,367
Restricted cash	110	110	110	110
Total cash, cash equivalents and restricted cash shown in the Condensed Consolidated Balance Sheets	$ 94,141	$ 117,477	$ 94,141	$ 117,477