v3.25.1
Long-term Debt - Financing Agreement and Credit Facility - Additional Information (Detail) - USD ($)
 1 Months Ended 3 Months Ended
May 13, 2024
May 31, 2024
Mar. 31, 2025
SYFOVRE [Member]      
Debt Instrument [Line Items]      
Minimum required sales to draw additional loan under credit facility $ 180,000,000    
Sixth Street Financing Agreement [Member]      
Debt Instrument [Line Items]      
Proceeds from initial draw amount under credit facility 358,200,000    
Proceeds from net of isuance cost 16,800,000    
Proceeds from credit facility 326,500,000 $ 326,500,000  
Senior Secured Credit Facility [Member] | Asset-Based Financing Arrangement [Member]      
Debt Instrument [Line Items]      
Available additional draw amount upon satisfaction of cash requirements 100,000,000    
Senior Secured Credit Facility [Member] | Sixth Street Financing Agreement [Member]      
Debt Instrument [Line Items]      
Maximum borrowing capacity 475,000,000    
Available initial draw amount under credit facility 375,000,000    
Available additional draw amount upon satisfaction of cash requirements 100,000,000    
Minimum cash requirements to draw additional loan under credit facility 50,000,000    
Minimum required sales to draw additional loan under credit facility 100,000,000    
Excercise option draw amount under credit facility $ 100,000,000    
Credit facility maturity date May 13, 2030    
Debt instrument, covenant description     The Sixth Street Financing Agreement contains customary covenants, including, without limitation, a financial covenant to maintain liquidity of at least $50.0 million if the Company’s market capitalization is below $3.0 billion, and negative covenants that, subject to certain exceptions, restrict indebtedness, liens, investments (including acquisitions), fundamental changes, asset sales and licensing transactions, dividends, modifications to material agreements, payment of subordinated indebtedness, and other matters customarily restricted in such agreements. Among other permissions, the Company is permitted, on terms and conditions set forth on the Sixth Street Financing Agreement, to enter into a separate asset-based financing arrangement with a third party in an amount of up to $100.0 million, which amount is increased to $200.0 million upon certain sales or market capitalization thresholds, and to have outstanding convertible unsecured notes in an amount equal to the greater of $400.0 million and 10% of the Company’s market capitalization, but not to exceed $600.0 million. The Company is subject to restrictions on sales and licensing transactions with respect to its core intellectual property, defined to include SYFOVRE, EMPAVELI, and other pegcetacoplan product assets, subject to certain exceptions, including certain transactions related to areas outside the United States and Europe.
Minimum required financial covenant if capitalization below three billion $ 50,000,000    
Market capitalization threshold percentage for credit facility 10.00%    
Senior Secured Credit Facility [Member] | Sixth Street Financing Agreement [Member] | Asset-Based Financing Arrangement [Member]      
Debt Instrument [Line Items]      
Revised Additional Available Draw Amount Upon Satisfaction of Sales or Market capitalization $ 200,000,000    
Minimum required convertible unsecured notes for additional loan amount 400,000,000    
Market capitalization threshold for credit facility $ 600,000,000    
Senior Secured Credit Facility [Member] | Sixth Street Financing Agreement [Member] | SOFR [Member]      
Debt Instrument [Line Items]      
Variable interest rate percentage on base rate 1.00%    
Credit Facility [Member] | Sixth Street Financing Agreement [Member]      
Debt Instrument [Line Items]      
Debt instrument effective interest rate 5.75%    
Credit Facility [Member] | Maximum [Member] | Sixth Street Financing Agreement [Member]      
Debt Instrument [Line Items]      
Percentage of prepayment premium 3.00%