Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenues:
Total revenues	$ 112	$ 383	$ 78
Operating expenses:
Research and development (Net of recoveries of $132, $25 and $3 from a related party)	288	257	159
General and administrative (Net of recoveries of $1, $ - and $ - from a related party)	104	72	43
Total operating expenses	392	329	202
Income (loss) from operations	(280)	54	(124)
Non-operating income (expense):
Interest and other income, net	16	1	1
Effective interest on liability for sale of future royalties	(2)
Total non-operating income, net	14	1	1
Income (loss) before income taxes	(266)	55	(123)
Income tax expense	(1)	(2)
Net income (loss)	$ (267)	$ 53	$ (123)
Net income (loss) per share, basic	$ (3.71)	$ 0.76	$ (2.24)
Net income (loss) per share, diluted	$ (3.71)	$ 0.71	$ (2.24)
Shares used to compute net income (loss) per share, basic	72.0	69.3	54.8
Shares used to compute net income (loss) per share, diluted	72.0	74.0	54.8
License and Development Services Revenue
Revenues:
Total revenues	$ 74	$ 345	$ 55
Other Collaboration Revenue
Revenues:
Total revenues	$ 38	$ 38	$ 23