Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2013

Summary of Significant Accounting Policies

Schedule of potentially dilutive securities not included in the calculation of diluted net loss per share

Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common equivalent shares):

	Three Months Ending March 31,
	2012	2013
	(Unaudited)
Convertible preferred stock outstanding	9,162,873	10,625,847
Common stock options	1,188,274	1,179,906
Total	10,351,147	11,805,753

Summary of the Company's historical computation of basic and diluted net loss per share

	Three Months EndingMarch 31,
	2012			2013
	(Unaudited)
Numerator
Net loss	$	(9,174,109	)	$	(6,253,233	)
Less dividends on preferred stock, not declared	(909,394		)	(1,094,324		)
Net loss attributable to common stockholders	$	(10,083,503	)	$	(7,347,557	)
Denominator
Common shares outstanding	3,010,101			3,010,101
Less weighted average unvested common shares	(1,378,374		)	(626,657		)
Weighted average shares used to compute net loss per share	1,631,727			2,383,444
Net loss per share, basic and diluted	$	(6.18	)	$	(3.08	)