Stock-Based Compensation

6 Months Ended

Jun. 30, 2014

Stock-Based Compensation

11. Stock-Based Compensation

The Company recognized stock-based compensation expense on all employee and non-employee awards as follows:

	For the three months ended June 30,					For the six months ended June 30,
(in thousands)	2014		2013			2014		2013
Research and development	$	410	$	(145	)	$	786	$	392
General and administrative		802		277			1,649		1,281
Stock-based employee compensation expense	$	1,212	$	132		$	2,435	$	1,673

The Company granted 23,800 and 104,300 stock options during the three and six months ended June 30, 2014 that had a weighted-average grant date fair value of $2.84 and $3.23 per share, respectively. The Company granted 1,315,500 and 1,426,400 stock options during the three and six months ended June 30, 2013 that had a weighted-average grant date fair value of $1.77 and $1.89 per share, respectively.

At June 30, 2014, total unrecognized compensation costs related to unvested stock options outstanding amounted to $6.2 million. The cost is expected to be recognized over a weighted-average period of 1.59 years.

On May 31, 2013, the Company extended the contractual life of 66,667 fully vested stock options held by one employee from 3 to 12 months.

On June 14, 2013, the Company extended the contractual life of 71,167 fully vested stock options held by one employee from 3 to 12 months.

On March 31, 2014, the Company extended the contractual life of 71,167 fully vested stock options held by one employee by an additional 9 months.

For the three months ended June 30, 2014 and 2013, the fair value of stock options was estimated on the date of grant using a Black-Scholes option valuation model with the following assumptions:

	For the three months ended June 30,
	2014			2013
Risk-free interest rate		1.98	%		1.65	%
Expected life in years		6			6
Expected volatility		94.07	%		95.45	%
Expected dividend yield		0			0

Stock option activity under the Company’s stock option plan for the six months ended June 30, 2014 is as follows:

(in thousands, except share and per share data)	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Contractual Term (Years)		Aggregate Intrinsic Value
Outstanding, December 31, 2013		6,747,302		$	3.81
Granted		104,300			3.54
Exercised		(583,038	)		2.26
Cancelled		(227,402	)		5.05
Outstanding, June 30, 2014		6,041,162		$	3.91		7.24	$	4,456
Vested and unvested expected to vest at June 30, 2014		5,988,240		$	4.11		5.61	$	4,417
Options exercisable, June 30, 2014		3,176,594		$	4.11		5.61	$	1,846
Options exercisable, December 31, 2013		3,471,935		$	4.01		5.03	$	2,654
Options available for future grant		5,317,831

A summary of the status of unvested restricted stock for the six months ended June 30, 2014 is as follows:

	Number of Shares			Weighted-Average Grant Date Fair Value
Non-vested, December 31, 2013		352,865		$	4.38
Granted		—			—
Vested		(48,433	)		4.51
Cancelled		(8,936	)		4.41
Non-vested, June 30, 2014		295,496		$	4.36

At June 30, 2014, total unrecognized compensation costs related to unvested restricted stock outstanding amounted to $0.7 million. The cost is expected to be recognized over a weighted-average period of 1.09 years.