Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities:
Net loss	$ (11,694)	$ (13,356)
Adjustments to reconcile net loss to cash used in operating activities:
Unrealized gain on equity investment	(4,397)	(360)
Change in accrued interest and accretion of discount on marketable securities	(921)	(729)
Stock-based compensation expense	1,968	1,917
Depreciation and amortization expense	136	145
Non-cash operating lease expense	266	253
Change in lease liability	(303)	289
Change in operating assets and liabilities:
Prepaid expenses and other current assets	853	258
Security deposit	0	12
Accounts payable	(107)	(121)
Accrued expenses	(2,486)	(419)
Net cash used in operating activities	(16,686)	(12,112)
Cash flows from investing activities:
Purchase of marketable securities	(9,793)	(9,758)
Sales/maturities of marketable securities	30,000	40,000
Purchases of property and equipment	(19)	(14)
Net cash provided by investing activities	20,188	30,229
Cash flows from financing activities:
Proceeds from exercise of options and purchases from employee stock purchase plan	228	67
Net cash provided by financing activities	228	67
Net increase in cash, cash equivalents and restricted cash	3,731	18,184
Cash, cash equivalents and restricted cash, at beginning of period	28,972	46,799
Cash, cash equivalents and restricted cash, at end of period	$ 32,703	$ 64,982