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 | ||