Net Income (Loss) Per Share - Basic and Diluted Net Income (loss) Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 27, 2024	Dec. 29, 2023	Dec. 30, 2022
Numerator:
Net income (loss) attributable to UCT	$ 23.7	$ (31.1)	$ 40.4
Shares used in computation — basic:
Weighted average common shares outstanding (in shares)	44.9	44.7	45.2
Shares used in computation — diluted:
Weighted average common shares outstanding (in shares)	44.9	44.7	45.2
Dilutive effect of common shares outstanding subject to repurchase (in shares)	0.4	0.0	0.5
Shares used in computing diluted net loss per share (in shares)	45.3	44.7	45.7
Net income (loss) per share attributable to UCT — basic (in dollars per share)	$ 0.53	$ (0.70)	$ 0.89
Net income (loss) per share attributable to UCT — diluted (in dollars per share)	$ 0.52	$ (0.70)	$ 0.88