Post-effective amendment to a registration statement that is not immediately effective upon filing

Loss Per Share - Reconciliation of Numerator and Denominator (Details)

v3.22.0.1
Loss Per Share - Reconciliation of Numerator and Denominator (Details) - USD ($)
$ / shares in Units, $ in Millions
2 Months Ended 4 Months Ended 12 Months Ended
Dec. 31, 2021
Oct. 19, 2021
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Net loss attributable to Mirion Technologies, Inc. (Successor) / Mirion Technologies (TopCo), Ltd. (Predecessor) shareholders $ (22.2) $ (105.7) $ (158.3) $ (119.1) $ (122.0)
Weighted average common shares outstanding — basic (in shares) 180.773 6.685 6.549 6.453 6.300
Weighted average common shares outstanding — diluted (in shares) 180.773 6.685 6.549 6.453 6.300
Net loss per common share attributable to Mirion Technologies, Inc. (Successor) / Mirion Technologies (TopCo), Ltd. (Predecessor) stockholders — basic (in dollars per share) $ 0.12 $ 15.81 $ 24.18 $ 18.45 $ 19.36
Net loss per common share attributable to Mirion Technologies, Inc. (Successor) / Mirion Technologies (TopCo), Ltd. (Predecessor) stockholders — diluted (in dollars per share) $ 0.12 $ 15.81 $ 24.18 $ 18.45 $ 19.36
Anti-dilutive employee share-based awards, excluded 0 0 0 0 0
Share-based awards          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Anti-dilutive employee share-based awards, excluded 0.003 0.200 0.300 0.400 0.500