Stock-Based Compensation

6 Months Ended

Jun. 30, 2019

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 June 30,				For the six months ended June 30,
(in thousands)	2019		2018		2019		2018
Research and development	$	297	$	609	$	729	$	1,212
General and administrative		1,502		1,102		2,526		4,158

Stock-based compensation expense	$	1,799	$	1,711	$	3,255	$	5,370

The Company granted an aggregate of 199,422 and 1,695,755 stock options during the three and six months ended June 30, 2019 with a weighted-average grant date fair value of $3.13 and $1.80 per share, respectively. The Company granted an aggregate of 198,000 and 205,500 stock options during the three and six months ended June 30, 2018 with a weighted average grant date fair value of $3.06 and $3.06 per share, respectively.

On January 6, 2019, the Company paid an accrued annual performance bonus by issuing 446,428 shares of common stock.

On June 13, 2019 the Company extended the contractual life of 52,500 fully vested stock options held by a director of the Company. Additionally, on June 13, 2019, the Company accelerated the vesting and extended the contractual life of 126,700 stock options held by a director. These extensions and acceleration of vesting resulted in additional stock compensation expense of $0.4 million in the three and six months ended June 30, 2019.

On February 15, 2018, the Company extended the contractual life of 751,667 fully vested stock options held by an officer of the Company by an additional nine months. Additionally, on March 12, 2018, the Company extended the contractual life of 117,500 fully vested stock options held by a director. These extensions resulted in additional stock compensation expense of $0 and $0.5 million in the three and six months ended June 30, 2018, respectively.

The Company recognizes forfeitures as they occur.

For the three months ended June 30, 2019 and 2018, 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,
	2019	2018
Risk-free interest rate	1.89 - 2.42%	2.66 - 2.91%
Expected life in years	5.75 - 6.25	6
Expected volatility	72.68 - 78.85%	81.48 - 81.66%
Expected dividend yield	0	0

Stock option activity under the Company’s stock option plan for the six months ended June 30, 2019 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, 2018		5,277,085		$	4.24
Granted		1,695,755			2.54
Exercised		(332,416	)		2.95
Cancelled		(1,562,833	)		4.14

Outstanding, June 30, 2019		5,077,591		$	3.78		7.91	$	12,463

Options exercisable, June 30, 2019		2,378,158		$	4.90		5.93	$	4,220

Options exercisable, December 31, 2018		3,099,935		$	5.15		4.93	$	88

Options available for future grant		4,069,982

At June 30, 2019, total unrecognized compensation costs related to unvested stock options outstanding amounted to $5.6 million. The cost is expected to be recognized over a weighted-average period of 1.58 years.

A summary of the status of unvested restricted stock for the six months ended June 30, 2019 is as follows:


	Number of Shares			Weighted-Average Grant Date Fair Value
Non-vested, December 31, 2018		682,070		$	3.47
Granted		1,393,536			2.24
Vested		(446,428	)		2.24
Cancelled		(74,599	)		3.41

Non-vested, June 30, 2019		1,554,579		$	2.90

At June 30, 2019, total unrecognized compensation costs related to unvested restricted stock outstanding amounted to $3.3 million. The cost is expected to be recognized over a weighted-average period of 1.54 years.