STOCK-BASED COMPENSATION

3 Months Ended

Mar. 31, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

8. STOCK-BASED COMPENSATION

The following table summarizes the Company’s stock awards granted for each of the periods indicated:

	For the Three Months Ended March 31,
	2016				2015
	Grants		Weighted Average Grant Date Fair Value		Grants		Weighted Average Grant Date Fair Value
Stock options*		1,205,776	$	11.92		1,607,544	$	10.35
Restricted stock awards**		25,775	$	13.71		6,000	$	13.90

Included in 2016 stock option grants are 287,500 options with performance conditions that are not currently probable of being achieved. If certain performance milestones are achieved within the required time frame, the Company may recognize up to $3.4 million of stock-based compensation related to these grants when performance is deemed probable. The remaining stock options granted during the periods presented in the table have only service-based criteria and vest over four years.

**	Included in 2016 restricted stock awards (“RSA”) are 18,755 shares granted to certain employees in lieu of a portion of their 2015 annual bonus payments. These RSA grants have six-month vesting schedules. The remaining RSAs will be fully vested by June 2017.

Stock-based Compensation Expense

For the three months ended March 31, 2016 and 2015, total stock-based compensation expense was $6.7 million and $14.2 million, respectively. Included in the amount for the three months ended March 31, 2015 is $8.7 million of stock-based compensation expense incurred in connection with the resignation of the Company’s former Chief Executive Officer (“CEO”). The following table summarizes stock-based compensation expense by function included within the unaudited condensed consolidated statements of operations and comprehensive loss:

	For the Three Months Ended March 31
	2016		2015
	(in thousands)
Research and development	$	2,449	$	2,446
General and administrative		4,241		11,710
Total stock-based compensation expense	$	6,690	$	14,156

The following table summarizes stock-based compensation expense by grant type included within the unaudited condensed consolidated statements of operations and comprehensive loss:

	For the Three Months Ended March 31
	2016		2015
	(in thousands)
Stock options	$	5,698	$	13,551
Restricted stock awards		184		42
Stock appreciation rights		115		147
Employee stock purchase plan		693		416
Total stock-based compensation expense	$	6,690	$	14,156