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Acquisitions - Summary of Changes to Goodwill Balance (Detail) - USD ($) $ in Millions | 3 Months Ended | 18 Months Ended
--- | --- | ---
Dec. 31, 2018 | Mar. 31, 2020
Goodwill [Line Items] |  |
Ending balance |  | $ 327.1
Counsyl Inc [Member] |  |
Goodwill [Line Items] |  |
Beginning balance | $ 94.9 | 94.9
Fair value adjustment to equipment |  | 0.7
Intangible adjustment |  | 2.9
Working capital adjustment | $ (1.1) | (1.1)
Change in deferred tax liability |  | 1.9
Ending balance |  | $ 99.3

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