Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023		Mar. 31, 2022
Cash flows from operating activities
Net Loss	$ (12,254)		$ (21,641)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock based compensation	1,481		9,240
Depreciation and amortization	17		38
Impairment loss on operating lease	66		0
Loss on disposal of fixed assets	73		0
Equity investment in Lighthouse, Inc.	(70)		0
Non-cash intangible impairment charge	5,900		0
Amortization of (discount) premium on available for sale investments	(139)		135
Change in deferred tax liabilities	(248)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	1,413		42
Right of use assets and lease liabilities	(45)		0
Other assets	0		165
Accounts payable	1,081		(1,180)
Accrued expenses and other current liabilities	(844)		(2,890)
Net cash used in operating activities	(3,569)		(16,091)
Cash flow from investing activities:
Purchase of investments	(7,691)		(8,957)
Proceeds from maturities of investments	13,277		22,375
Proceeds from disposal of fixed assets	90		0
Purchase of property and equipment	(136)		(5)
Net cash provided by investing activities	5,540		13,413
Cash flows from financing activities:
Payments of finance leases	(6)		0
Proceeds from issuance of common stock on exercise of stock options	56		14
Proceeds from issuance of common stock in connection with open market sales agreement, net of issuance costs	0		608
Net cash provided by financing activities	50		622
Effect of exchange rate changes on cash	114		(104)
Net increase (decrease) in cash and cash equivalents	2,135		(2,160)
Cash and cash equivalents at beginning of period	44,579	[1]	69,724
Cash and cash equivalents at end of period	46,714		67,564
Supplemental disclosures of non-cash information:
Right-of-use asset and financing lease liability reduction as a result of lease modification	(70)		0
Right-of-use asset and operating lease liability reduction as a result of lease modification	$ 0		$ (640)

[1] The balance sheet as of December 31, 2022 is derived from the audited financial statements as of that date.