CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 248,600	$ 193,018
Marketable securities	741,318	372,670
Prepaid expenses and other current assets	8,740	12,329
Total current assets	998,658	578,017
Marketable securities	39,863	52,269
Property and equipment, net	28,323	28,449
Operating lease assets	22,204	23,251
Restricted cash	1,867	4,200
Other long-term assets	2,797	2,733
Total assets	1,093,712	688,919
Current liabilities:
Accounts payable	14,971	11,298
Accrued expenses and other current liabilities	42,264	28,803
Operating lease liabilities, current portion	2,785	2,437
Total current liabilities	60,020	42,538
Operating lease liabilities, net of current portion	31,948	34,110
Financing liability, related party (Notes 5 and 7)	31,687	16,770
2027 convertible senior notes, net (Note 6)	335,006
Financing liability (Notes 5 and 7)	31,687	16,770
Other long-term liabilities	2	2
Total liabilities	490,350	110,190
Commitments and contingencies (Notes 13 and 14)
Stockholders’ equity:
Preferred stock, $0.0001 par value: 10,000,000 shares authorized; no shares issued and outstanding as of September 30, 2022 and December 31, 2021
Common stock, $0.0001 par value: 500,000,000 shares authorized; 156,243,808 and 147,719,523 shares issued and outstanding as of September 30, 2022 and December 31, 2021, respectively	16	15
Additional paid-in capital	1,473,099	1,195,944
Accumulated other comprehensive income (loss)	5,194	(986)
Accumulated deficit	(874,947)	(616,244)
Total stockholders’ equity	603,362	578,729
Total liabilities and stockholders’ equity	$ 1,093,712	$ 688,919