CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOW - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities:
Net loss	$ (32,808)	$ (29,361)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	775	726
Amortization and premium of marketable securities, net	(3,313)	(1,256)
Loss on sale or disposal of assets	8
Stock-based compensation expense	7,202	4,340
Changes in operating assets and liabilities:
Accounts and other receivables	(43)	(967)
Prepaid and other current assets	(6,209)	2,722
Accounts payable and accrued expenses	(4,781)	(3,448)
Other liabilities	(1,469)	(1,325)
Net cash used in operating activities	(40,638)	(28,569)
Cash flows from investing activities:
Sales and maturities of marketable securities	77,311	127,000
Purchases of marketable securities	(392,178)	(73,846)
Acquisition of property and equipment	(344)	(585)
Net cash (used in ) provided by investing activities	(315,211)	52,569
Cash flows from financing activities:
Net proceeds from stock issuances	432,298
Proceeds from issuance of stock from employee benefit plans	3,814	694
Net cash provided by financing activities	436,112	694
Net increase in cash and cash equivalents	80,263	24,694
Cash and cash equivalents at beginning of period	34,814	29,429
Cash and cash equivalents at end of period	115,077	54,123
Non-cash investing activities
Accrued construction in progress	$ 105	$ 134