9. Net Loss Per Share

Basic and diluted net loss per share for the three months ended March 31, 2018 and 2017 was calculated as follows (in thousands except share and per share amounts):

	Three Months Ended			Three Months Ended
	March 31,			March 31,
	2018			2017
Numerator:
Net loss	$	(10,622	)	$	(9,414	)
Accretion of preferred stock to redemption value	—			(244		)

Net loss attributable to common stockholders	$	(10,622	)	$	(9,658	)

Denominator:
Weighted average number of common shares outstanding - basic and diluted	12,449,421			6,945,623

Net loss per share attributable to common stockholders - basic and diluted	$	(0.85	)	$	(1.39	)

The Company’s potentially dilutive securities include stock options and warrants. These securities were excluded from the computations of diluted net loss per share for the three months ended March 31, 2018 and 2017, as the effect would be to reduce the net loss per share. The following table includes the potential common shares, presented based on amounts outstanding at each period end, that were excluded 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	Three Months Ended
	March 31,	March 31,
	2018	2017

Options to purchase common stock	2,250,080	1,867,458
Warrants assumed from Macrocure	54,516	54,516
Warrants issued with the Private Placement	2,958,094	—

	5,262,690	1,921,974