Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2012

Summary of Significant Accounting Policies

Summary of the outstanding securities not included in the computation of diluted net loss per common share as their inclusion would be anti-dilutive

	Years Ended December 31,
	2012		2011		2010
Common stock options		5,521,584		5,821,073		5,326,979
Unvested restricted stock		35,122		82,450		140,613