Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Operating Activities:
Net loss	$ (155,140)	$ (124,822)
Adjustments to reconcile net loss to net cash used in operating activities:
Accretion of discount on convertible notes	0	752
Depreciation and amortization of property and equipment	2,883	2,188
Write down of property and equipment, net	177	0
Right of use asset	1,605	0
Stock-based compensation	21,316	22,200
Accretion of discount on investments, net	1,132	2,089
Expense in connection with warrant issuance	0	7,578
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(1,278)	1,016
Accounts payable and accrued expenses	7,189	(2,842)
Operating lease liabilities	(96)	17
Finance lease liability	134	1,644
Other liabilities	(43)	(42)
Net cash used in operating activities	(122,121)	(90,222)
Investing activities:
Purchases of investments	(177,460)	(226,484)
Proceeds from maturities of investments	222,074	234,146
Payments made to acquire right of use asset	0	(18)
Purchases of property and equipment	(5,355)	(5,655)
Net cash provided by investing activities	39,259	1,989
Financing activities:
Issuance of common stock, pursuant to exercise of stock options	308	10,191
Issuance of common stock, net of issuance costs	0	26,354
Issuance of common stock pursuant to the at-the-market offering program, net of issuance costs	46,540	0
Net cash provided by financing activities	46,848	36,545
Net change in cash, cash equivalents and restricted cash	(36,014)	(51,688)
Cash, cash equivalents and restricted cash at beginning of period	234,037	298,666
Cash, cash equivalents and restricted cash at end of period	198,023	246,978
Supplemental disclosure of non-cash financing and investing activities:
Accrued purchases of property and equipment	1,747	1,132
Unrealized loss on investments	(435)	(55)
Conversion of convertible notes into common stock	0	(40,693)
Reclassification of construction in process from finance right of use asset	0	39
Supplemental cash flow information:
Cash paid for interest	$ 0	$ 148