Net Loss Per Share

12 Months Ended

Dec. 31, 2011

Net Loss Per Share [Abstract]

Net Loss Per Share

13. Net Loss per Share

The following is a reconciliation of the numerator (net loss) and the denominator (number of shares) used in the basic and diluted earnings per share calculations:

	Year Ended December 31,
	2011			2010			2009
Basic and diluted:
Net loss	$	(32,031,175	)	$	(19,923,487	)	$	(27,494,457	)
Weighted average common shares outstanding		54,826,266			50,522,001			43,344,324
Net loss per share	$	(0.58	)	$	(0.39	)	$	(0.63	)

The following table sets forth the number of common shares that were excluded from the computation of diluted earnings per share because their inclusion would have been anti-dilutive as follows:

	December 31,
	2011		2010		2009
Shares outstanding
Restricted shares		526,588		33,282		858,938
Shares issuable upon exercise of:
Options to purchase common stock		5,627,332		4,711,082		4,675,450
Restricted stock units		988,202		-		-
Warrants		10,381,613		10,381,613		9,623,711
		17,523,735		15,125,977		15,158,099