Earnings per Share (Tables)

12 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Reconciliation of Weighted Average Common Shares Outstanding for Purposes of Calculating Basic and Diluted Earnings Per Share

The calculations of basic and diluted net income (loss) per share and basic and diluted weighted average shares outstanding are as follows for the fiscal years ended September 30, 2018, 2017 and 2016 (in thousands, except per share data):

	Year Ended September 30,
	2018		2017		2016
Income (loss) income from continuing operations	$	67,717	$	10,687	$	(85,457)
Income from discontinued operations, net of tax		48,747		51,925		15,981
Net income		116,464		62,612		(69,476)
Net loss attributable to noncontrolling interest		111		—		—
Net income (loss) attributable to Brooks Automation, Inc.	$	116,575	$	62,612	$	(69,476)
Weighted average common shares outstanding used in computing basic earnings per share		70,489		69,575		68,507
Dilutive restricted stock units		448		910		—
Weighted average common shares outstanding used in computing diluted earnings per share		70,937		70,485		68,507
Basic net income (loss) per share attributable to Brooks Automation, Inc. common stockholders:
Income (loss) from continuing operations	$	0.96	$	0.15	$	(1.25)
Income from discontinued operations, net of tax		0.69		0.75		0.23
Basic net income (loss) per share attributable to Brooks Automation, Inc.	$	1.65	$	0.90	$	(1.01)
Diluted net income (loss) per share attributable to Brooks Automation, Inc. common stockholders:
Income (loss) from continuing operations	$	0.95	$	0.15	$	(1.25)
Income from discontinued operations, net of tax		0.69		0.74		0.23
Diluted net income (loss) per share attributable to Brooks Automation, Inc. common stockholders	$	1.64	$	0.89	$	(1.01)