Net Loss per Common Share

12 Months Ended

Dec. 31, 2012

Earnings Per Share [Abstract]

Net Loss per Common Share

Net Loss per Common Share

Basic net loss per share 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 of common stock equivalents. Diluted net loss per share 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, preferred stock, stock options and warrants 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.

The following table presents the computation of basic and diluted net loss per common share (in thousands, except share and per share data):

	Years Ended December 31,
	2012			2011			2010
Historical net loss per share
Numerator
Net loss attributable to common stockholders	$	(23,321	)	$	(18,087	)	$	(16,213	)
Denominator
Weighted-average common shares outstanding (basic and diluted)	20,779,450			6,064,542			3,352,331
Basic and diluted net loss per share	$	(1.12	)	$	(2.98	)	(4.84		)

The numerator was not adjusted for the stock dividend paid on the Series AA preferred stock as the impact is not material. Potentially dilutive securities not included in the calculation of diluted net loss per common share because to do so would be anti-dilutive are as follows (in common equivalent shares):

	As of December 31,
	2012	2011	2010
Preferred stock(1)	—	—	8,438,417
Common stock warrants	—	—	—
Common stock options	3,752,413	3,515,051	2,932,673
	3,752,413	3,515,051	11,371,090

(1) Amounts for the Series BB, C, D and E preferred stock conversions are computed based on the initial public offering price of 7.00 per share.