Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities
Net loss	$ (204,212)	$ (170,060)	$ (88,045)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	927	855	1,010
Net amortization of premiums and discounts on marketable securities	(1,462)	0	(86)
Stock-based compensation	21,522	18,409	7,172
Other non-cash items	763	723	148
Changes in operating assets and liabilities:
Accounts receivable	(30,000)	0	0
Prepaid expenses and other current assets	3,863	(2,734)	(1,950)
Other assets	0	(718)	(700)
Accounts payable	947	483	942
Accrued expenses	13,594	12,570	7,280
Operating lease right-of-use assets	2,777	1,829	1,642
Operating lease liabilities	(2,539)	(1,827)	(1,281)
Deferred revenue	143,709	(43)	(828)
Other liabilities	748	525	0
Net cash used in operating activities	(49,363)	(139,988)	(74,696)
Cash flows from investing activities
Maturities of marketable securities	97,000	0	37,500
Purchase of marketable securities	(247,519)	0	0
Purchase of property and equipment	(2,197)	(648)	(473)
Net cash used in investing activities	(152,716)	(648)	37,027
Cash flows from financing activities
Proceeds from exercise of stock options	1,331	1,837	3,138
Proceeds from purchases of common stock under ESPP	1,065	640	561
Payment of employee tax obligations related to vesting of restricted stock units	0	(259)	0
Proceeds from issuance of debt, net of issuance costs	0	24,042	(197)
Repayment of debt	0	(5,486)	0
Payments under finance lease obligations	(272)	(215)	(116)
Net cash provided by financing activities	153,017	63,646	230,412
Increase (decrease) in cash, cash equivalents and restricted cash	(49,062)	(76,990)	192,743
Cash, cash equivalents and restricted cash, beginning of period	178,425	255,415	62,672
Cash, cash equivalents and restricted cash, end of period	129,363	178,425	255,415
Supplemental disclosures of non-cash activities:
Purchases of property and equipment in accounts payable and accrued expenses	753	0	102
Debt financing costs in accrued expenses	150	0	0
Common stock issuance costs in accounts payable and accrued expenses	131	0	0
Cash paid for interest	2,463	429	234
Right-of-use assets obtained in exchange for operating lease liabilities	298	3,783	9,980
Right-of-use assets obtained in exchange for financing lease liabilities	0	609	0
Public Stock Offering
Cash flows from financing activities
Net proceeds from issuance of common stock	0	0	163,990
At Market Equity Offering Program
Cash flows from financing activities
Net proceeds from issuance of common stock	$ 150,893	$ 43,087	$ 63,036