Stockholders' Equity (Tables)

6 Months Ended

Jun. 30, 2013

Summary of Share-based Compensation Expense Related to Stock Options Units by Expense Category

The following table summarizes share-based compensation expense related to stock options by expense category (in thousands):

	ThreeMonthsEnded				SixMonthsEnded
	June30,				June30,
	2013		2012		2013		2012
Research and development	$	251	$	248	$	647	$	248
General and administrative		1,892		2,462		4,962		2,462
Share-based compensation expense included in operating expenses	$	2,143	$	2,710	$	5,609	$	2,710

Summary of Stock Option Activity and Related Data

A summary of the Company’s stock option activity and related data for the three months ended June 30, 2013 is as follows:

	Outstanding Options
	Number of Shares		Weighted-Average ExercisePrice
Balance at December31, 2012		592,230,567	$	0.0655
Granted		—		—
Forfeited/Expired		2		148,500
Balance at June 30, 2013		592,230,565	$	0.0655