6. Net Loss per Share

Basic net loss per share is computed by dividing net loss by the weighted average number of common shares outstanding. Included in net loss is the Series A preferred dividend from preferred shares issuance of $61,000 and $122,000 for the three and six months ended June 30, 2019 and $61,000 and $120,000 for the three and six months ended June 30, 2018, respectively. Net loss for the three and six months ended June 30, 2019 also includes the Series B deemed dividend of $117,000 and $515,000. The deemed dividend relates to the discount provided to preferred stockholders upon conversion of their preferred stock to common shares and is subtracted from net loss (see Note 8). Diluted net loss per share is computed by dividing net loss by the weighted average number of common shares outstanding including the effect of common share equivalents. Diluted net loss per share assumes the issuance of potentially dilutive common shares outstanding for the period and adjusts for any changes in income and the repurchase of common shares that would have occurred from the assumed issuance, unless such effect is anti-dilutive. The number of options and warrants for the purchase of common stock that were excluded from the computations of net loss per common share for the three and six months ended June 30, 2019 were 843,119 and 18,915,851, respectively, and for the three and six months and ended June 30, 2018 were 12,168,515 and 32,054,809, respectively.

The following tables set forth the computation of diluted net loss per weighted average number of shares outstanding attributable to Synthetic Biologics, Inc. and Subsidiaries for the three and six months ended June 30, 2019 and 2018 (in thousands except share and per share amounts):


	Three months ended June 30, 2019					Six months ended June 30, 2019
	Net loss		Shares	Per Share		Net Loss		Shares	Per Share
	(Numerator)		(Denominator)	Amount		(Numerator)		(Denominator)	Amount
Net loss - Basic	$	(3,709)	16,465,314	$	(0.23)	$	(7,680)	16,063,283	$	(0.48)

Dilutive shares related to warrants		—	—		—		—	—		—

Net loss - Dilutive	$	(3,709)	16,465,314	$	(0.23)	$	(7,680)	16,063,283	$	(0.48)


	Three months ended June 30, 2018					Six months ended June 30, 2018
	Net loss		Shares	Per Share		Net Loss		Shares	Per Share
	(Numerator)		(Denominator)	Amount		(Numerator)		(Denominator)	Amount
Net loss - Basic	$	(4,258)	3,683,383	$	(1.16)	$	(6,634)	3,678,389	$	(1.80)

Dilutive shares related to warrants		—	—		—		—	—		—

Net loss - Dilutive	$	(4,258)	3,683,383	$	(1.16)	$	(6,634)	3,678,389	$	(1.80)