Available-for-Sale Debt Securities - Gross Unrealized Losses and Fair Value Available-for-Sale Debt Securities in Unrealized Loss Position (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	$ 298.2	$ 334.9
Less Than 12 Months, Unrealized Losses	(0.5)	(1.1)
12 Months or Longer, Fair Value	0.0	0.0
12 Months or Longer, Unrealized Loss	0.0	0.0
Total Fair Value	298.2	334.9
Total Unrealized Losses	$ (0.5)	(1.1)
Securities of government-sponsored entities
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value		123.8
Less Than 12 Months, Unrealized Losses		(0.6)
12 Months or Longer, Fair Value		0.0
12 Months or Longer, Unrealized Loss		0.0
Total Fair Value		123.8
Total Unrealized Losses		$ (0.6)

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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NEUROCRINE BIOSCIENCES INC 10-K