11. 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:

	Three Months Ended March 31,
	2013			2012
	(in thousands)
Numerator:
Net (loss) income attributable to common stockholders, basic and diluted	$	(1,121	)	$	1,657
Denominator:
Weighted average common stock, basic	35,597			33,969
Dilutive effect of stock-based awards	—			2,663
Weighted average common stock, dilutive	35,597			36,632
Net (loss) income per share attributable to common stockholders:
Basic	$	(0.03	)	$	0.05
Diluted	$	(0.03	)	$	0.05

For the three months ended March 31, 2013, we excluded all stock options and RSUs from the computation of diluted net loss per share due to the net loss for the quarter. For the three months ended March 31, 2012, 2,033,129 options to purchase common stock were not included in the computation of diluted net income per share as the inclusion would have been anti-dilutive.