Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating activities:
Net loss	$ (163,918)	$ (107,641)	$ (73,812)
Reconciliation of net loss to net cash used in operating activities:
Stock-based compensation	28,268	17,352	10,427
Depreciation and amortization	983	922	948
Noncash lease expense	406	340	278
Accretion of purchase discounts and amortization of premiums on investment securities, net	34	422	(227)
Noncash license revenues		(1,078)
Loss on equity method investment	1,010	0	0
Change in fair value of derivative asset	(600)	0	0
Other, net		(1)	(17)
Increase (decrease) in cash resulting from changes in:
Prepaid expenses and other assets	215	(4,361)	(1,623)
Accounts payable and accrued expenses, compensation and related expenses	10,994	6,293	2,723
Deferred revenue	8,341
Operating lease liability	(938)	(836)	(724)
Net cash used in operating activities	(115,205)	(88,588)	(62,027)
Investing activities:
Purchases of investment securities	(329,817)	(125,404)	(135,592)
Maturities of investment securities	157,493	69,357	135,995
Purchases of property and equipment	(1,656)	(436)	(186)
Net cash (used in) provided by investing activities	(173,980)	(56,483)	217
Financing activities:
Proceeds from issuance of common stock, net of $13.0 million (2021) and $7.5 million (2020) transaction costs	117,242	249,542	114,283
Proceeds from exercise of stock options	4,721	3,137	288
Net cash provided by financing activities	121,963	252,679	114,571
Net change in cash, cash equivalents and restricted cash	(167,222)	107,608	52,761
Cash, cash equivalents and restricted cash - beginning of period	201,195	93,587	40,826
Cash, cash equivalents and restricted cash - end of period	33,973	201,195	93,587
Components of cash, cash equivalents and restricted cash:
Cash and cash equivalents	32,672	200,695	93,087
Restricted cash	1,301	500	500
Cash, cash equivalents and restricted cash - end of period	33,973	201,195	93,587
Non-cash financing activity:
Investment in Radionetics	0	1,010
Derivative asset		68
Stock issued under Stock Purchase Plan	1,618	1,021	691
Amounts accrued for purchases of property and equipment		130	6
Change in unvested stock liability	$ 2	$ 21	$ 26