4. Loss Per Share

The Company calculates basic net loss per share is computed by dividing the net loss for the period by the weighted average number of shares of common stock outstanding for the period. Diluted net loss per share is computed by dividing the net loss by the weighted average number of shares of common stock and dilutive common stock equivalents then outstanding. Common stock equivalents consist of shares of common stock issuable upon the exercise of stock options and warrants.

The following table sets forth the computation for basic and diluted loss per share:

	Three Months Ended June 30,				Six Months Ended June 30,
	2012		2013		2012		2013
	( Unaudited )				( Unaudited )

Numerator:
Net loss	$	(2,729,661)	$	(1,297,154)	$	(5,854,250)	$	(2,121,458)
Numerator for basic and diluted earnings per share	$	(2,729,661)	$	(1,297,154)	$	(5,854,250)	$	(2,121,458)
Denominator:
Denominator for basic and diluted earnings per share — weighted-average shares		23,873,270		32,798,010		23,873,270		32,797,819
Basic and diluted loss per share	$	(0.11)	$	(0.04)	$	(0.25)	$	(0.06)

Outstanding stock options to purchase 2,492,160 and 2,465,390 shares of Common Stock of the Company for the periods ended June 30, 2012 and 2013, respectively, were excluded from the calculation of diluted loss per share as their effect would have been antidilutive. Also excluded from the calculation were 270,000 unvested shares of restricted common stock for both of the periods ended June 30, 2012 and 2013.