Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (68,144)	$ (55,043)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	22,028	12,732
Depreciation and amortization	4,187	1,958
Change in fair value of success payment liabilities	(3,851)	9,967
Net amortization or accretion on marketable securities	475	483
Non-cash lease (income) expense	(214)	1,040
Loss on property equipment and disposals	84	0
Change in fair value of warrants	(28)	43
Changes in operating assets and liabilities:
Prepaid expenses, other current assets and other assets	(397)	(342)
Accounts payable	2,937	634
Accrued liabilities and other current liabilities	(6,393)	(4,695)
Deferred revenue	(558)	(2,437)
Operating lease liabilities, non-current	2,135	2,063
Other non-current liabilities	(113)	0
Net cash used in operating activities	(47,852)	(33,597)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of property and equipment	(9,733)	(19,190)
Purchases of marketable securities	(96,196)	(48,291)
Sales and maturities of marketable securities	79,807	204,158
Net cash (used in) provided by investing activities	(26,122)	136,677
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from exercise of stock options	2,555	884
Net cash provided by financing activities	2,555	884
Net (decrease) increase in cash, cash equivalents and restricted cash	(71,419)	103,964
Cash, cash equivalents and restricted cash at beginning of period	294,294	140,872
Cash, cash equivalents and restricted cash at end of period	222,875	244,836
Represented by:
Cash and cash equivalents	222,596	244,370
Restricted cash	279	466
Total	222,875	244,836
SUPPLEMENTAL CASH FLOW INFORMATION
Cash received for amounts related to tenant improvement allowances	2,042	2,063
Cash paid for amounts included in the measurement of lease liabilities	2,672	1,362
Non-cash investing and financing activities:
Purchases of property and equipment included in accounts payable and accrued liabilities	107	13,543
Remeasurement of operating lease right-of-use asset for lease modification	5	4,208
Deferred offering costs included in accounts payable and accrued liabilities	$ 0	$ 398