Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (96,573)	$ (88,974)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	15,381	19,203
Depreciation	27	33
Non-cash lease expense	174	162
Net amortization of premiums and discounts on short-term investments	(5,908)	182
Amortization of debt issuance costs and discount	328	110
Fair value change in warrant liability	118	29
Write-off of deferred offering costs	337
Unrealized foreign exchange gain and loss	(26)	(12)
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(17,793)	2,657
Accounts payable	3,584	(708)
Accrued expenses and other current liabilities	3,782	460
Operating lease liability	(171)	(151)
Net cash used in operating activities	(96,740)	(67,009)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchase of short-term and long-term marketable securities	(374,909)
Proceeds from maturities of short-term marketable securities	138,500	37,620
Net cash (used in) provided by investing activities	(236,409)	37,620
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the exercise of stock options	2,817	2,229
Proceeds from the issuance of common stock pursuant to employee stock purchase plan purchases	313	178
Proceeds from the issuance of common in a follow-on public offering		216,200
Proceeds from the issuance of common stock pursuant to the ATM offering	124,212
Proceeds from the issuance of common stock pursuant to registered direct offering	211,217
Proceeds from the issuance of common stock pursuant to private offering		25,000
Proceeds from loan payable	15,000	10,000
Payment of debt and equity issuance costs	(745)	(698)
Net cash provided by financing activities	352,814	252,909
Net increase in cash, cash equivalents and restricted cash	19,665	223,520
Cash, cash equivalents and restricted cash at the beginning of the period	249,881	150,591
Cash, cash equivalents and restricted cash at the end of the period	269,546	374,111
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid for interest	1,715	189
NON-CASH INVESTING AND FINANCING INFORMATION:
Change in net unrealizable (loss) gain on marketable securities	$ (543)	27
Warrant liability costs reclassified to additional paid-in equity on vested warrants issued	330
Debt and equity issuance costs included in accounts payable and accrued expenses and other current liabilities		371
Deferred offering costs reclassified to additional paid-in equity	$ 364	$ 150
Stock options exercises included in other current assets	$ 67