Net Income Per Share Attributable to Common Stockholders

The computations for basic and diluted net income per share attributable to common stockholders are as follows:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2013			2012			2013			2012
	(in thousands)
Numerator:
Net income	$	1,309		$	1,667		$	1,579		$	1,105
Net income attributable to participating securities	(2		)	(1,252		)	(2		)	(841		)
Net income attributable to common stockholders - basic	1,307			415			1,577			264
Undistributed earnings reallocated to participating securities	1			1,249			—			839
Net income attributable to common stockholders - diluted	$	1,308		$	1,664		$	1,577		$	1,103
Denominator:
Weighted-average shares used in computing net income per share attributable to common stockholders - basic	32,088			5,843			31,789			5,540
Effect of potentially dilutive securities:
Convertible preferred stock	—			17,597			—			17,597
Common stock options	4,159			3,105			3,915			2,829
Contingently issuable shares related to an acquisition	—			—			—			6
Weighted-average shares used in computing net income per share attributable to common stockholders - diluted	36,247			26,545			35,704			25,972
Net income per share attributable to common stockholders:
Basic	$	0.04		$	0.07		$	0.05		$	0.05
Diluted	$	0.04		$	0.06		$	0.04		$	0.04

All of the convertible preferred stock automatically converted to common stock on a 1-for-1 basis in connection with the consummation of the Company's initial public offering. For the three and nine months ended September 30, 2012, the amounts presented in the table above were the weighted average shares of common stock underlying outstanding shares of convertible preferred stock.

The following shares were excluded in the calculation of diluted net income per share because their inclusion would have been anti-dilutive:



	Three Months Ended		Nine Months Ended
	September 30,		September 30,
	2013	2012	2013	2012
	(in thousands)
Common stock options	394	1,108	956	1,031
	394	1,108	956	1,031