v3.26.1
Income Taxes - Narrative (Details) - USD ($)
$ in Thousands
12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Income Taxes [Line Items]      
Effective income tax rate reconciliation, percent (50.40%) (7.10%) 0.50%
Valuation allowance $ 897,209 $ 701,219  
Valuation allowance increase (decrease) 196,000    
Interest and penalties related to unrecognized tax benefits 0 $ 0 $ 0
Switzerland      
Income Taxes [Line Items]      
Net operating losses 1,512,900    
United States      
Income Taxes [Line Items]      
Net operating losses $ 890,700    
Annual net operating loss utilization limitation percentage 80.00%    
Federal research tax credit carryforwards $ 66,000    
United Kingdom      
Income Taxes [Line Items]      
Net operating losses 613,400    
States in U.S and Canada      
Income Taxes [Line Items]      
Federal research tax credit carryforwards $ 10,800