Stock-Based Compensation

3 Months Ended

Mar. 31, 2015

Stock-Based Compensation

10. Stock-Based Compensation

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

	For the three months
	ended March 31,
(in thousands)	2015		2014
Research and development	$	295	$	376
General and administrative		798		847
Stock-based employee compensation expense	$	1,093	$	1,223

The Company granted 50,000 and 80,500 stock options during the three months ended March 31, 2015 and 2014 that had a weighted-average grant date fair value of $6.58 and $3.34 per share, respectively.

At March 31, 2015, total unrecognized compensation costs related to unvested stock options outstanding amounted to $7.7 million. The cost is expected to be recognized over a weighted-average period of 1.63 years.

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.

On March 31, 2014, the Company extended the contractual life of 33,333 fully vested stock options and 66,667 unvested stock options held by one employee.

On September 8, 2014, the Company extended the contractual life of 82,834 fully vested stock options and 23,333 unvested stock options held by one employee by an additional 3 months.

On September 15, 2014, the Company extended the contractual life of 39,167 fully vested stock options and 113,333 unvested stock options held by one employee.

For the three months ended March 31, 2015 and 2014, 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 March 31,
	2015	2014
Risk-free interest rate	1.63 - 1.64%	1.76 - 2.11%
Expected life in years	6	6
Expected volatility	85.48 - 86.81%	94.46 - 94.55%
Expected dividend yield	0	0

Stock option activity under the Company’s stock option plan for the three months ended March 31, 2015 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, 2014		6,505,663		$	4.07
Granted		50,000			9.10
Exercised		(592,200	)		4.29
Cancelled		(39,166	)		4.26
Outstanding, March 31, 2015		5,924,297		$	4.09		6.36	$	39,564
Vested and unvested expected to vest at March 31, 2015		5,878,611		$	4.08		5.33	$	39,259
Options exercisable, March 31, 2015		3,185,297		$	4.08		5.33	$	21,297
Options exercisable, December 31, 2014		3,781,162		$	4.10		5.80	$	4,130
Options available for future grant		4,572,935

A summary of the status of unvested restricted stock for the three months ended March 31, 2015 is as follows:

	Number of Shares			Weighted-Average Grant Date Fair Value
Non-vested, December 31, 2014		144,508		$	4.70
Granted		—			—
Vested		(48,435	)		4.51
Cancelled		—			—
Non-vested, March 31, 2015		96,073		$	4.79

At March 31, 2015, total unrecognized compensation costs related to unvested restricted stock outstanding amounted to $0.5 million. The cost is expected to be recognized over a weighted-average period of 1.00 years.