v3.25.3

Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expenses capitalized amount	$ 0.2	$ 0.2	$ 0.5	$ 0.9
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant-date fair value (in dollars per share)			$ 31.86	$ 19.38
Stock-based compensation, Intrinsic value of options exercised			$ 94.1	$ 14.3
Total unrecognized stock-based compensation related to unvested stock option awards granted	$ 76.5		$ 76.5
Unrecognized stock-based compensation related to unvested stock, expected to recognize over weighted-average period			2 years 9 months 18 days
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized stock-based compensation related to unvested stock option awards granted	$ 39.0		$ 39.0
Unrecognized stock-based compensation related to unvested stock, expected to recognize over weighted-average period			2 years
Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			3 years
2023 Executive PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation related to unvested stock, expected to recognize over weighted-average period			1 year 7 months 6 days
Total unrecognized stock-based compensation	$ 11.9		$ 11.9

Amount of cost capitalized for award under share-based payment arrangement.

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Mirum Pharmaceuticals, Inc. 10-Q