15. Net income per share attributable to common stockholders

The following table sets forth the computation of basic and diluted net income per share attributable to common stockholders:

	Years ended December 31,

	2012		2011		2010
	(in thousands)
Numerator:
Net income attributable to common stockholders, basic	$	7,295	$	4,662	$	10,554
Accretion of convertible preferred stock		—		—		5,020

Net income attributable to Boingo Wireless, Inc., diluted	$	7,295	$	4,662	$	15,574

Denominator:
Weighted average common stock, basic		34,774		24,014		5,834
Effect of dilutive convertible preferred stock		—		—		22,846
Effect of dilutive stock options		2,543		3,457		3,204
Effect of dilutive common stock warrants		—		10		15

Weighted average common stock, diluted		37,317		27,481		31,899

Net income per share attributable to common stockholders:
Basic	$	0.21	$	0.19	$	1.81
Diluted	$	0.20	$	0.17	$	0.49

The following outstanding securities were not included in the computation of diluted net income per share as the inclusion would have been anti-dilutive:

	Years ended December 31,

	2012		2011		2010
	(in thousands)
Convertible preferred stock		—		7,699		—
Stock options		2,518		2,172		—
Preferred stock warrants		—		26		26

Total		2,518		9,897		26