Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating activities:
Net loss	$ (245,595)	$ (221,863)	$ (169,069)
Adjustments to reconcile net loss to net cash used in operating activities:
Accretion of discount on convertible notes	0	0	753
Depreciation and amortization of property and equipment	4,944	3,932	3,240
Amortization of finance lease right of use asset	2,154	2,334	2,133
Impairment of acquired intangible asset	574	0	0
Write down of property and equipment	311	236	261
Stock-based compensation	39,406	31,009	29,237
Accretion of discount and amortization of premium on investments, net	(10,168)	134	2,887
Expense in connection with warrant issuance	0	0	12,781
Changes in operating assets and liabilities:
Prepaid expenses and other assets	2,694	(3,593)	1,307
Accounts payable and accrued expenses	10,147	9,674	(4,827)
Operating lease liability and right of use asset, net	137	(120)	(11)
Finance lease liability	139	172	201
Other liabilities	341	(57)	(56)
Net cash used in operating activities	(194,916)	(178,142)	(121,163)
Investing activities:
Purchases of investments	(390,920)	(376,327)	(245,875)
Proceeds from maturities of investments	309,326	272,894	272,443
Cash proceeds from acquisition of business, net of cash paid	0	42,726	0
Payments made to acquire right of use asset	(36)	(261)	(95)
Purchases of property and equipment	(16,436)	(8,358)	(7,620)
Net cash (used in) provided by investing activities	(98,066)	(69,326)	18,853
Financing activities:
Issuance of common stock, pursuant to exercise of stock options	2,231	631	11,327
Treasury stock repurchase	0	(47)	0
Issuance of common stock, pursuant to sale of treasury stock	56	0	0
Issuance of common stock, pursuant to exercise of warrants	7	0	0
Net cash provided by financing activities	208,401	155,288	37,681
Net change in cash, cash equivalents and restricted cash	(84,581)	(92,180)	(64,629)
Cash, cash equivalents and restricted cash at beginning of period	141,857	234,037	298,666
Cash, cash equivalents and restricted cash at end of period	57,276	141,857	234,037
Supplemental disclosure of non-cash financing and investing activities:
Accrued purchases of property and equipment, ending balance	1,077	2,095	728
Operating lease liabilities	2,929	0	0
Unrealized gain (loss) on investments	676	(196)	(119)
Conversion of convertible notes into common stock	0	0	40,694
Issuance of common stock related to acquisition	0	70,724	0
Reclassification of construction in process from finance right of use asset	0	261	98
Supplemental cash flow information:
Cash paid for interest	0	0	148
Public Offering
Financing activities:
Issuance of common stock, net of issuance costs	188,885	108,138	26,354
At-the-Market Offering Program
Financing activities:
Issuance of common stock, net of issuance costs	$ 17,222	$ 46,566	$ 0