Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2013

Equity [Abstract]

Summary of Share-based Compensation Expense

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

	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
Research and development
Stock options	$	250	$	267	$	897	$	503
Restricted stock	7		12		51		23
Restricted stock units	—		—		—		—
General and administrative
Stock options	1,892		2,384		6,854		4,527
Restricted stock	593		46		714		86
Restricted stock units	—		253		52		533
Share-based compensation expense included in operating expenses	$	2,742	$	2,962	$	8,568	$	5,672

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

	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
Research and development	$	250	$	267	$	897	$	503
General and administrative	1,892		2,384		6,854		4,527
Stock option share-based compensation expense included in operating expenses	$	2,142	$	2,651	$	7,751	$	5,030

Summary of Stock Option Activity and Related Data

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

	Outstanding Options
	Number of Shares		Weighted-Average Exercise Price
Balance at December 31, 2012	592,230,567		$	0.0655
Granted
Forfeited/Expired	(5	)	88,740
Canceled	(592,230,471	)	0.0655
Balance at September 30, 2013	91		$	16,192