Income Taxes - Additional Information (Detail) - USD ($)		12 Months Ended
	Aug. 16, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Line Items]
Current tax expense		$ 0
Research and development expense		356,235,000	$ 326,163,000	$ 283,166,000
Deferred tax expense		0
Inflation reduction of corporate alternative minimum tax	15.00%
Inflation reduction of excise tax on stock repurchases	1.00%
Federal operating loss carryforwards		$ 1,800,000,000
Federal net operating loss carryforwards, limitation percentage		80.00%
Federal orphan drug tax credit carry forwards		$ 40,100,000
Tax credit carry forwards expiration period		2034
Change in amount of deferred tax assets		$ 141,900,000
Valuation allowance		735,194,000	593,286,000
Valuation allowance, increase (decrease), amount		141,900,000	122,700,000	94,500,000
Accrued interest or penalties related to uncertain tax positions		0	0
Uncertain tax positions		0	$ 0	$ 0
Begin to Expire 2033 [Member]
Income Tax Disclosure [Line Items]
Federal operating loss carryforwards		$ 30,400,000
Federal net operating loss carryforwards expiration year		2033
State operating loss carryforwards		$ 991,200,000
State net operating loss carryforwards expiration year		2033
Domestic Tax Authority [Member]
Income Tax Disclosure [Line Items]
Research and development tax credits carryforwards		$ 81,400,000
Research and development tax credits carryforwards expiration year		2031
State and Local Jurisdiction [Member]
Income Tax Disclosure [Line Items]
Research and development tax credits carryforwards		$ 15,300,000
Research and development tax credits carryforwards expiration year		2032