Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Cash flow from operating activities
Net loss	$ (199,544)	$ (226,538)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	48,478	40,713
Depreciation and amortization	4,522	2,583
Noncash lease expense	6,049	1,701
Amortization of premiums on investments	2,012	2,804
Acquired in-process research and development	1,250
Effective interest on liability for sale of future royalties	1,437
Changes in operating assets and liabilities:
Receivable from collaboration partners ($718,014 and $326 from a related party)	715,809	178
Prepaid expenses and other current assets	(2,152)	(5,290)
Other long-term assets (($1,856) and $0 to a related party)	(1,636)	750
Accounts payable	(54)	(5,424)
Accrued research and development	13,240	19,163
Other accrued liabilities	(4,130)	5,082
Deferred revenue (($73,323) and ($23,133) to a related party)	(78,345)	(28,383)
Operating lease liabilities	(2,911)	(1,405)
Other long-term liabilities	3,714	(2)
Net cash provided by (used in) operating activities	507,739	(194,068)
Cash flow from investing activities
Purchases of short-term and long-term investments	(1,085,392)	(584,850)
Proceeds from maturities of short-term and long-term investments	490,860	572,140
Sales of short-term and long-term investments	143,091	7,500
Purchases of property and equipment	(5,620)	(17,572)
Purchases of in-process research and development	(5,500)
Collaboration reimbursements of in-process research and development from a related party	2,750
Net cash used in investing activities	(459,811)	(22,782)
Cash flow from financing activities
Proceeds from issuance of common stock ($0 and $220,235 from a related party)		220,235
Proceeds from sale of future royalties	5,000
Proceeds from issuance of common stock pursuant to equity award plans	16,805	5,440
Repurchase of unvested shares of stock		(6)
Net cash provided by financing activities	21,805	225,669
Net increase in cash, cash equivalents and restricted cash	69,733	8,819
Cash, cash equivalents and restricted cash at beginning of period	150,919	173,618
Cash, cash equivalents and restricted cash at end of period	220,652	182,437
Supplemental disclosure of cash flow information
Income taxes paid	2,743
Non-cash investing and financing activities:
Unpaid portion of property and equipment purchases included in accounts payable and accrued liabilities	1,335	4,605
Unpaid portion of other assets included in accrued research and development		3,000
Vesting of early exercised stock options and restricted stock	$ 52	$ 529