Condensed Consolidated Balance Sheets (Unaudited) - USD ($)	Jun. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 172,802,000	$ 93,075,000
Short-term marketable securities	235,610,000	219,275,000
Prepaid expenses and other current assets	9,593,000	8,326,000
Total current assets	418,005,000	320,676,000
Long-term marketable securities	51,836,000	9,642,000
Property and equipment, net	17,990,000	22,327,000
Operating lease assets	33,546,000	37,861,000
Restricted cash	408,000	408,000
Other assets	3,959,000	4,383,000
Total assets	525,744,000	395,297,000
Current liabilities:
Accounts payable	2,142,000	2,000,000
Accrued expenses and other current liabilities	18,465,000	20,186,000
Operating lease liabilities	4,286,000	3,970,000
Total current liabilities	24,893,000	26,156,000
Operating lease liabilities, net of current portion	49,682,000	51,889,000
Other liabilities	82,000	566,000
Total liabilities	74,657,000	78,611,000
Commitments and contingencies (Note 11)
Stockholders' equity:
Preferred stock, $0.0001 par value; 80,000,000 shares authorized at June 30, 2024 and December 31, 2023; no shares issued and outstanding at June 30, 2024 and December 31, 2023
Common stock, $0.0001 par value; 800,000,000 shares authorized at June 30, 2024 and December 31, 2023; 273,163,958 and 151,462,103 shares issued at June 30, 2024 and December 31, 2023, respectively; 273,039,997 and 151,090,227 shares outstanding at June 30, 2024 and December 31, 2023, respectively	27,000	15,000
Additional paid-in capital	1,155,487,000	922,607,000
Accumulated other comprehensive (loss) income	(196,000)	77,000
Accumulated deficit	(704,231,000)	(606,013,000)
Total stockholders' equity	451,087,000	316,686,000
Total liabilities and stockholders' equity	$ 525,744,000	$ 395,297,000