Net Loss per Share

9 Months Ended

Sep. 30, 2015

9. Net Loss per Share

Basic and diluted net loss per share attributable to common stockholders was calculated as follows:

	Three Months Ended September 30,						Nine Months Ended September 30,
	2015			2014			2015			2014

Numerator:
Net loss	$	(10,633	)	$	(2,657	)	$	(15,849	)	$	(5,920	)
Accretion of convertible preferred stock to redemption value	(995		)	(479		)	(2,353		)	(1,394		)

Net loss attributable to common stockholders	$	(11,628	)	$	(3,136	)	$	(18,202		$	(7,314	)

Denominator:
Weighted average shares of common stock outstanding	2,730,427			2,730,427			2,730,427			2,730,427
Less: Weighted average shares of unvested restricted common stock outstanding	(455,810		)	(935,518		)	(574,742		)	(1,054,451		)

Weighted average common shares outstanding used in calculating net loss per share attributable to common stockholders, basic and diluted	2,274,617			1,794,909			2,155,685			1,675,976

Net loss per share attributable to common stockholders, basic and diluted	$	(5.11	)	$	(1.75	)	$	(8.44	)	$	(4.36	)

To calculate net loss attributable to common stockholders for the period, the Company reduced the net loss for the accretion of issuance costs and cumulative dividends accrued but not paid through August 28, 2015, and the remaining cumulative dividends accrued but not paid through September 30, 2015.

The Company’s potential dilutive securities, which include stock options, unvested restricted common stock and Preferred Stock, have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The following potential common shares, presented based on amounts outstanding at each period end, were excluded from the calculation of diluted net loss per share attributable to common stockholders for both the three and nine months ended September 30, 2015 and 2014 because including them would have had an anti-dilutive effect:

	2015	2014

Stock options to purchase common stock	1,140,524	168,110
Unvested restricted common stock	399,757	879,466
Convertible preferred stock (as converted to common stock)	11,677,076	7,924,919

	13,217,357	8,972,495