3. Net Income Per Share

The computation of basic and diluted net income per share was as follows (in millions, except per share data):

	Three Months Ended					Six Months Ended
	December 31,					December 31,
	2017			2016		2017			2016
Numerator:
Net income/(loss)	$	(82.4	)	$	22.8	$	(108.9	)	$	26.5
Denominator:
Shares, basic		34.1			35.1		33.8			35.0
Effect of dilutive share-based awards		-			0.8		-			0.7
Shares, diluted		34.1			35.9		33.8			35.7
Net income/(loss) per share:
Basic	$	(2.42	)	$	0.65	$	(3.22	)	$	0.76
Diluted	$	(2.42	)	$	0.64	$	(3.22	)	$	0.74

Our basic net income per share amounts for each period presented have been computed using the weighted average number of shares of common stock outstanding over the period measured. Our diluted net income per share amounts for each period presented include the weighted average effect of potentially dilutive shares. We use the “treasury stock” method to determine the dilutive effect of our stock options, deferred stock units, or DSUs, market stock units, or MSUs, performance stock units, or PSUs, and our convertible notes.

Dilutive net income per share amounts do not include the potential weighted average effect of 3,334,776 and 1,900,374 shares of common stock related to certain share-based awards that were outstanding during the three months ended December 31, 2017 and 2016, respectively, and 3,020,056 and 1,586,410 shares of common stock related to certain share-based awards that were outstanding during the six months ended December 31, 2017, and 2016, respectively. These share-based awards were not included in the computation of diluted net income per share because their effect would have been antidilutive.