CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net loss	$ (100,666)	$ (38,700)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	1,983	587
Net amortization of premiums and accretion of discounts on marketable securities	194	0
Amortization of operating lease right-of-use asset	80	0
Depreciation expense	4	0
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	3,212	(1,178)
Other non-current assets	3,060	0
Accounts payable	12,899	3,164
Accrued expenses	20,260	12,386
Operating lease liabilities	(69)	0
Other non-current liabilities	(6)	0
Net cash used in operating activities	(59,049)	(23,741)
Cash flows from investing activities:
Maturities of marketable securities	49,000	0
Net cash provided by investing activities	49,000	0
Cash flows from financing activities:
Proceeds from exercises of stock options	47	0
Payments for repurchases of unvested restricted common stock	(2)	0
Net cash provided by financing activities	45	0
Net decrease in cash and cash equivalents	(10,004)	(23,741)
Cash and cash equivalents at beginning of period	542,224	114,988
Cash and cash equivalents at end of period	532,220	91,247
Supplemental disclosure of non-cash investing and financing activities:
Operating lease right-of-use asset recognized upon adoption of ASC 842	1,728	0
Deferred offering and issuance costs included in accrued expenses	$ 0	$ 55