Net Loss Per Share Applicable to Common Stockholders (Tables)

6 Months Ended

Jun. 30, 2013

Earnings Per Share [Abstract]

Common Stock Excluded from Calculation of Diluted Net Loss Per Share

The following common stock equivalents were excluded from the calculation of diluted net loss per share applicable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect. The convertible preferred stock numbers shown in the table are on a common stock equivalent basis as a result of the reverse stock split described in Note 1, Overview and Basis of Presentation.

	Three Months Ended June 30,				Six Months Ended June 30,
	2013		2012		2013		2012
Convertible preferred stock		19,731,564		19,731,564		19,731,564		19,731,564
Stock options		3,657,145		3,287,171		3,657,145		3,287,171
Unvested restricted stock		63,840		200,757		63,840		200,757
		23,452,549		23,219,492		23,452,549		23,219,492