Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating activities
Net loss	$ (17,059)	$ (17,275)
Reconciliation of net loss to net cash used in operating activities:
Stock-based compensation	1,464	627
Non-cash interest expense	165	0
Accretion of premium and interest on marketable securities	(153)	13
Depreciation expense	10	4
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	901	960
Accounts payable	(2,320)	(4,765)
Accrued expenses	161	6,412
Net cash used in operating activities	(16,831)	(14,024)
Investing activities
Purchase of marketable securities	0	(79,271)
Proceeds from sales and maturities of marketable securities	26,600	0
Net cash provided by (used in) investing activities	26,600	(79,271)
Financing activities
Proceeds from issuance of common stock upon stock option exercises	228	19
Common stock repurchase	(12)	0
Net cash provided by financing activities	216	19
Increase (decrease) in cash and cash equivalents	9,985	(93,276)
Cash and cash equivalents, beginning of year	45,917	146,284
Cash and cash equivalents, end of year	55,902	53,008
Supplemental disclosure of cash flow information
Interest paid	532	$ 0
Supplemental disclosure of non-cash financing activities
Fair value of warrants issued with debt	$ 400