Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Operating activities
Net loss	$ (116,806)	$ (225,358)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	13,397	8,916
Stock-based compensation	33,984	59,341
Accretion and amortization of premiums and discounts on investments, net	(8,492)	989
Amortization of collaboration contract assets	7,196	1,546
Deferred revenue	(41,116)	(959)
Changes in fair value of stock price appreciation milestones liability	(3,160)	(15,131)
Grant income from CIRM award	(4,000)	0
Changes in operating assets and liabilities:
Accounts receivable	36,942	(1,547)
Prepaid expenses and other assets	14,512	(10,924)
Accounts payable and accrued expenses	(27,047)	10,865
Right-of-use assets and lease liabilities, net	(1,036)	(557)
Net cash used in operating activities	(95,626)	(172,819)
Investing activities
Purchases of property and equipment	(5,972)	(28,889)
Purchases of investments	(308,844)	(297,694)
Maturities of investments	382,128	440,222
Net cash provided by investing activities	67,312	113,639
Financing activities
Issuance of common stock from equity incentive plans, net of issuance costs	265	7,690
Net cash provided by financing activities	265	7,690
Net change in cash, cash equivalents and restricted cash	(28,049)	(51,490)
Cash, cash equivalents and restricted cash at beginning of the period	76,560	148,810
Cash, cash equivalents and restricted cash at end of the period	48,511	97,320
Supplemental schedule of noncash investing and financing activities
Purchases of property and equipment in accounts payable	168	1,988
Right-of use assets obtained in exchange for lease obligations	$ 62	$ 682