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	$ (7,837)	$ (7,162)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	194	165
Share-based compensation	1,267	1,574
Amortization of premium and discount on marketable securities	(593)	0
ROU asset amortization	287	270
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(250)	(1,313)
Accounts payable	(2,257)	(611)
Accrued expenses	(2,747)	(595)
Operating lease liability	(293)	(270)
Net cash used in operating activities	(12,229)	(7,942)
Cash flows from investing activities:
Purchases of property and equipment	0	(194)
Purchases of marketable securities	(54,919)	0
Proceeds from sale or maturities of marketable securities	59,188	0
Proceeds from sale of equipment	0	1
Net cash provided by (used in) investing activities	4,269	(193)
Cash flows from financing activities:
Proceeds from exercise of stock options	41	0
Net cash provided by financing activities	41	0
Net change in cash and cash equivalents	(7,919)	(8,135)
Cash and cash equivalents at beginning of period	34,946	144,514
Cash and cash equivalents at end of period	27,027	136,379
Supplemental disclosure of cash flow information
Unrealized gain on marketable securities	(156)	0
Acquisition of equipment included in accrued expenses	$ 0	$ 57