Net Loss Per Common Share

Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding for the period, without consideration for common stock equivalents. Diluted net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common share equivalents outstanding for the period determined using the treasury-stock method. For purposes of this calculation, outstanding options and unvested RSUs settleable in shares of common stock are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive.

Historical outstanding anti-dilutive securities not included in diluted net loss per share attributable to common stockholders calculation is as follows (in millions):



	Three Months Ended September 30,		Nine Months Ended September 30,
	2016	2015	2016	2015
Options outstanding to purchase common stock	0.8	1.6	0.8	1.6
Unvested restricted stock units	3.7	4.2	3.7	4.2
Total	4.5	5.8	4.5	5.8