CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Operating activities
Net loss	$ (90,619)	$ (79,727)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	26,309	20,565
Lease impairment charge	4,925	0
Depreciation and amortization	3,399	1,779
Premiums and discounts on available-for-sale marketable securities	(7,093)	(2,743)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(2,076)	(3,994)
Accounts receivable	15,000	0
Contract asset	2,059	(1,585)
Other long term assets	227	0
Accounts payable	106	(513)
Accrued expenses and other current liabilities	(7,591)	(6,252)
Deferred revenue	(32,203)	(18,537)
Operating lease right-of-use assets	1,244	2,055
Operating lease liabilities	4,149	9,554
Other assets and liabilities	(363)	174
Net cash used in operating activities	(82,527)	(79,224)
Investing activities
Purchase of property and equipment, net	(12,091)	(14,777)
Purchases of investments	(526,860)	(114,477)
Maturities of investments	223,986	189,677
Net cash (used in) provided by investing activities	(314,965)	60,423
Financing activities
Proceeds from issuance of common stock and accompanying pre-funded warrants from public offering, net of underwriting discounts and issuance costs	301,373	0
Proceeds from issuance of common stock through At-The Market Sales Agreement, net of issuance costs	48,740	0
Proceeds from stock option exercises	4,562	2,163
Proceeds from employee stock purchase plan	1,135	962
Payments on finance leases	(642)	(661)
Net cash provided by financing activities	355,168	2,464
Net decrease in cash, cash equivalents and restricted cash	(42,324)	(16,337)
Cash, cash equivalents and restricted cash at beginning of period	115,777	74,524
Cash, cash equivalents and restricted cash at end of period	73,453	58,187
Supplemental disclosure of cash flow activities
Right-of-use assets obtained in exchange for new operating lease liabilities	0	48,833
Cash paid for interest	90	78
Supplemental disclosure of noncash investing and financing activities
Property and equipment purchases included in accounts payable and accrued expenses	853	1,061
Cash and cash equivalents	67,612	52,386
Restricted cash	5,841	5,801
Total cash, cash equivalents, and restricted cash	$ 73,453	$ 58,187