Income Taxes - Additional Information (Details)	12 Months Ended
	Dec. 31, 2021 USD ($) Ownership Audit	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Income Taxes Disclosure [Line Items]
Percentage of stock owned resulting in an ownership change	50.00%
Aggregate period	3 years
Number of ownership changes | Ownership	0
Valuation allowance	$ 236,478,000	$ 594,752,000	$ 502,209,000
(Decrease) Increase for the current period	(358,274,000)	92,543,000
Accrued interest and penalties related to uncertain tax positions	0	0
Unrecognized tax benefits	$ 24,220,000	21,131,000	$ 17,460,000
Number of federal, state or foreign audits in process | Audit	0
Prepaid Expenses and Other Current Assets
Income Taxes Disclosure [Line Items]
Income tax receivable	$ 2,900,000	$ 0
Federal Orphan Drug Tax Credit
Income Taxes Disclosure [Line Items]
Research and development tax credit	119,600,000
Federal
Income Taxes Disclosure [Line Items]
Net operating loss carryforwards	22,100,000
Federal | Research Tax Credit Carryforward
Income Taxes Disclosure [Line Items]
Research and development tax credit	13,500,000
State and Local Jurisdiction
Income Taxes Disclosure [Line Items]
Net operating loss carryforwards	420,000,000
State and Local Jurisdiction | Research Tax Credit Carryforward
Income Taxes Disclosure [Line Items]
Research and development tax credit	24,000,000
Foreign Income Tax
Income Taxes Disclosure [Line Items]
Net operating loss carryforwards	$ 65,200,000