Net Loss Per Share

12 Months Ended

Dec. 31, 2014

Net Loss Per Share

Net Loss Per Share

11. Net Loss Per Share

The Company applies the two-class method for calculating basic earnings per share. Under the two-class method, net income (loss) is reduced by cumulative preferred stock dividends and the residual amount is allocated between common stock and other participating securities based on their participation rights. Participating securities comprised of restricted common stock, which participate in dividends, if declared, by the Company. As the Company has reported a net loss for all periods, and the participating securities were not contractually obligated to share in the losses of the Company, accordingly, no losses were allocated to the participating securities.

Basic earnings per share is calculated by dividing net income (loss) attributable to common stockholders by the weighted average number of shares of common stock outstanding, net of the weighted average unvested restricted stock subject to repurchase by the Company, if any, during the period. Diluted earnings per share is calculated by dividing the net income (loss) attributable to common stockholders by the weighted average number of common shares outstanding, adjusted for the effects of potentially dilutive common stock, which are comprised of stock options, restricted stock units and stock warrants, using the treasury-stock method, and convertible preferred stock, using the if-converted method. Because the Company reported losses attributable to common stockholders for all periods presented, all potentially dilutive common stock are antidilutive for those periods.

The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders during the years ended December 2014, 2013 and 2012 (in thousands, except per share data):

	Year Ended December 31,
	2014		2013		2012
Net loss	$	(48,429)	$	(25,056)	$	(74,495)
Weighted-average common shares outstanding		70,837		58,540		55,828
Net loss per share — basic and diluted	$	(0.68)	$	(0.43)	$	(1.33)

The following table presents the number of anti-dilutive shares excluded from the calculation of diluted net loss per share attributable to common stockholders at December 31, 2014, 2013 and 2012 (in thousands):

	December 31,
	2014	2013	2012
Options to purchase common stock	25,590	18,363	15,419
Common stock warrants	3,926	5,931	5,154
Conversion of convertible preferred stock	—	2,857	—
Unvested restricted stock awards	828	55	122
Contingently redeemable shares	—	—	126
Convertible promissory notes	—	—	3,444
Total shares excluded from net loss per share attributable to common stockholders	30,344	27,206	24,265