Condensed Consolidated Statements of Operations (unaudited) - USD ($) shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Revenues:
Total revenues	$ 29,000,000	$ 27,000,000	$ 54,000,000	$ 45,000,000
Operating expenses:
Research and development (Net of recoveries of $34, $36, $67 and $66 from a related party)	84,000,000	70,000,000	165,000,000	131,000,000
General and administrative	28,000,000	26,000,000	58,000,000	50,000,000
Total operating expenses	112,000,000	96,000,000	223,000,000	181,000,000
Loss from operations	(83,000,000)	(69,000,000)	(169,000,000)	(136,000,000)
Non-operating income (expense):
Interest and other income, net	9,000,000	3,000,000	18,000,000	3,000,000
Effective interest on liability for sale of future royalties		(1,000,000)	(1,000,000)	(1,000,000)
Total non-operating income, net	9,000,000	2,000,000	17,000,000	2,000,000
Loss before income taxes	(74,000,000)	(67,000,000)	(152,000,000)	(134,000,000)
Income tax expense	(1,000,000)	0	(3,000,000)	(1,000,000)
Net loss	$ (75,000,000)	$ (67,000,000)	$ (155,000,000)	$ (135,000,000)
Net loss per share, basic	$ (1.04)	$ (0.93)	$ (2.13)	$ (1.88)
Net loss per share, diluted	$ (1.04)	$ (0.93)	$ (2.13)	$ (1.88)
Shares used to compute net income loss per share, basic	73.2	71.8	73.1	71.5
Shares used to compute net income loss per share, diluted	73.2	71.8	73.1	71.5
License and Development Services Revenue
Revenues:
Total revenues	$ 19,000,000	$ 17,000,000	$ 36,000,000	$ 25,000,000
Other Collaboration Revenue
Revenues:
Total revenues	$ 10,000,000	$ 10,000,000	$ 18,000,000	$ 20,000,000