Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities:
Net loss	$ (72,928)	$ (56,353)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	12,757	7,856
Depreciation and amortization expense	2,420	2,194
Amortization (accretion) of premium (discount) on marketable securities, net	(240)	412
Loss on sale of property and equipment	28	0
Loss on impairment of leasehold improvements	5,037	0
Changes in operating assets and liabilities:
Tenant receivable	(1,778)	0
Prepaid expenses and other current assets	(3,097)	(2,140)
Operating lease right-of-use assets	2,185	1,421
Other noncurrent assets	(3,466)	(30)
Accounts payable	(936)	322
Accrued expenses and other current liabilities	(2,179)	(171)
Operating lease liability	3,229	(1,975)
Net cash used in operating activities	(58,968)	(48,464)
Cash flows from investing activities:
Purchases of property and equipment	(7,468)	(2,183)
Purchases of marketable securities	(154,037)	0
Maturities of marketable securities	0	165,900
Net cash (used in) provided by investing activities	(161,505)	163,717
Cash flows from financing activities:
Proceeds from public offering of common stock, net of underwriting discounts and commissions	0	211,876
Payment of offering costs	(50)	(550)
Proceeds from issuance of common stock from public ATM offering, net of commissions and offering costs	2,726	0
Proceeds from exercise of stock options and other types of equity, net	917	2,604
Net cash provided by financing activities	3,593	213,930
Net increase in cash, cash equivalents and restricted cash	(216,880)	329,183
Cash, cash equivalents and restricted cash at beginning of period	380,837	64,940
Cash, cash equivalents and restricted cash at end of period	163,957	394,123
Supplemental disclosure of noncash investing and financing information:
Purchases of property and equipment included in accounts payable and accrued expenses	544	333
Unrealized Loss on Marketable Securities	(339)	(5)
Offering costs included in accounts payable and accrued expenses	$ 0	$ 118