v3.25.3

Common Stock - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended		9 Months Ended
	Sep. 26, 2025	Sep. 16, 2024	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024	Aug. 30, 2024
Class of Stock [Line Items]
Common stock, shares authorized			500,000,000		500,000,000		500,000,000	500,000,000
Common stock, par value			$ 0.0001		$ 0.0001		$ 0.0001	$ 0.0001
Net proceeds after deducting underwriting discounts and commissions					$ 0	$ 174,542
offering costs					$ 254	$ 3,735
Common stock, shares issued			44,715,498		44,715,498		33,421,525
Common stock, shares outstanding			44,715,498		44,715,498		33,421,525
Common Stock
Class of Stock [Line Items]
Net proceeds after deducting underwriting discounts and commissions		$ 170,500
Initial Public Offering \| Common Stock
Class of Stock [Line Items]
Number of shares sold		11,730,000		11,730,000
Stock price per share		$ 16.00
offering costs		$ 17,200
Public offering \| Common Stock
Class of Stock [Line Items]
Number of shares sold	11,108,055		11,108,055
Stock price per share	$ 18.00
Net proceeds after deducting underwriting discounts and commissions	$ 187,400
offering costs	$ 12,500
Restricted Stock
Class of Stock [Line Items]
Stock related to unvested portion of early exercised common stock options			2,514		2,514		12,608

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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MBX Biosciences, Inc. 10-Q