Net Income Per Share (Tables)

9 Months Ended

Sep. 28, 2018

Earnings Per Share [Abstract]

Basic and Diluted Net Income (loss) Per Share

The following is a reconciliation of the numerators and denominators used in computing basic and diluted net income (loss) per share (in thousands, except per share data):

	Three Months Ended					Nine Months Ended
	September 28,			September 29,		September 28,		September 29,
	2018			2017		2018		2017
Numerator:
Net income (loss) attributable to Ultra Clean Holdings, Inc.	$	(5,997	)	$	19,716	$	37,704	$	54,236
Denominator:
Shares used in computation — basic:
Weighted average common shares    outstanding		38,930			33,540		38,152		33,342
Shares used in computation — diluted:
Shares used in computing basic net    income per share		38,930			33,540		38,152		33,342
Dilutive effect of common shares    outstanding subject to repurchase		—			813		588		856
Dilutive effect of options outstanding		—			7		5		18
Weighted average shares used in    computing diluted net income per share		38,930			34,360		38,745		34,216
Net income per share attributable to Ultra Clean Holdings, Inc. — basic	$	(0.15	)	$	0.59	$	0.99	$	1.63
Net income per share attributable to Ultra Clean Holdings, Inc. — diluted	$	(0.15	)	$	0.57	$	0.97	$	1.59