Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating activities
Net loss	$ (11,188)	$ (15,323)
Reconciliation of net loss to net cash used in operating activities:
Stock-based compensation expense	1,220	1,209
Net gain on warrants inherited in acquisition of Quellis		1,542
Right-of-use asset - operating lease	142
Other non-cash items	(26)	(79)
Changes in assets and liabilities:
Prepaid expenses and other assets	(864)	163
Lease liability - operating lease	(145)	(15)
Accounts payable	140	(627)
Accrued expenses	(2,532)	571
Net cash used in operating activities	(13,253)	(12,559)
Investing activities
Purchases of short-term investments	(95,923)	(81,702)
Sales and maturities of short-term investments	290,920	54,603
Purchases of property and equipment	(5)
Net cash provided by (used in) investing activities	194,992	(27,099)
Financing activities
Proceeds from exercise of stock options	37
Net cash provided by financing activities	37
Net increase (decrease) in cash, cash equivalents and restricted cash	181,776	(39,658)
Cash, cash equivalents and restricted cash, beginning of period	20,688	86,629
Cash, cash equivalents and restricted cash, end of period	202,464	$ 46,971
Supplemental disclosure of non-cash transactions:
Conversion of Series X Preferred Stock into common stock	$ 1,074