Stock-Based Compensation - Employee Stock Option (Details) - Stock Options $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2026 USD ($) $ / shares
Stock-Based Compensation
Weighted average grant-date fair value (in dollars per share) \| $ / shares	$ 19.04
Intrinsic value of stock options vested and expected to vest	$ 66.6
Intrinsic value of stock options exercisable	41.5
Compensation cost not yet recognized	$ 57.3
Weighted average period compensation cost is expected to be recognized (in years)	2 years 6 months

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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+ Details

Celldex Therapeutics, Inc. 10-Q