15.

Net Loss per Share

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


	Three Months Ended March 31,
	2019			2018
Numerator:
Net loss	$	(10,873	)	$	(7,367	)
Accruing dividends on Series A convertible preferred stock		(592	)		(740	)

Net loss attributable to common stockholders	$	(11,465	)	$	(8,107	)

Denominator:
Weighted average common shares outstanding—basic and diluted		1,717,808			457,971
Net loss per share attributable to common stockholders—basic and diluted	$	(6.67	)	$	(17.70	)

The Company has included 107,371 shares of redeemable common stock in its computation of basic and diluted weighted average common shares outstanding for the three months ended March 31, 2019 and 2018 as this class of stock participates in losses similarly to other common stockholders.

The Company’s potentially dilutive securities included outstanding stock options, convertible preferred stock, and warrants to purchase shares of convertible preferred stock for the three month period ended March 31, 2018 and included outstanding stock options and warrants to purchase common stock for the three month period ended March 31, 2019. These potentially dilutive securities have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share, and thus they are considered “anti-dilutive.” 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 Company excluded the following potential common shares, presented based on amounts outstanding at each period end and adjusted for the Exchange Ratio and Reverse Stock Split, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect:


	Three Months Ended March 31,
	2019		2018
Options to purchase common stock		1,037,089		538,429
Convertible preferred stock (as converted to common stock)		—		3,556,147
Warrants to purchase common stock (presented on an as-converted, as exchanged, split-adjusted basis.		493,927		423,416

		1,531,016		4,517,992