Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Cash flows from operating activities:
Net loss	$ (209,445)	$ (177,297)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	23,543	20,517
Depreciation and amortization expense	338	299
Amortization of debt issuance costs and discount	491	0
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(2,582)	(2,799)
Accounts payable	(2,818)	9,401
Accrued expense	24,550	13,279
Accrued interest, net of interest received on maturity of investments	(419)	734
Net cash used in operating activities	(166,342)	(135,866)
Cash flows from investing activities:
Purchases of marketable securities	(130,693)	(339,371)
Sales and maturities of marketable securities	271,180	318,769
Purchases of property and equipment, net of disposals	(188)	(96)
Net cash provided by (used in) investing activities	140,299	(20,698)
Cash flows from financing activities:
Proceeds from issuances of stock, excluding related parties, net of transaction costs	0	151,249
Proceeds from the exercise of common stock options	0	485
Proceeds from issuance of loan payable	50,000	0
Payment of debt issuance costs	(886)	0
Net cash provided by financing activities	49,114	151,734
Net increase (decrease) in cash and cash equivalents	23,071	(4,830)
Cash and cash equivalents at beginning of period	36,269	54,004
Cash and cash equivalents at end of period	59,340	49,174
Supplemental disclosure of cash flow information:
Obtaining a right-of-use asset in exchange for a lease liability	$ 583	$ 376