Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2016

Our stock-based compensation expense for the three months ended March 31 was as follows:


	Three months ended
	March 31,
	2016			2015
Research and development expense	$	313,378		$	583,669
General and administrative expense		1,539,048			725,225

Total stock-based compensation	$	1,852,426		$	1,308,894

Effect on basic and diluted net loss per share	$	(0.19	)	$	(0.23	)

A summary of our stock option activity for the three months ended March 31, 2016 is as follows:


	Number of options			Weighted-average exercise price ($) per share
Outstanding options at December 31, 2015		173,261			34.80
Granted		10,000			3.60
Exercised		—			—
Cancelled		(27,430	)		34.20

Outstanding options at March 31, 2016		155,831			32.76

The following is a summary of changes in unvested options:


Unvested Options	Number of Options			Weighted Average Grant Date Fair Value
Unvested options at December 31, 2015		140,000		$	8.28
Granted(1)		10,000		$	3.60
Vested		—		$	145.68
Cancelled		(25,417	)	$	8.52

Unvested options at March 31, 2016		124,583		$	7.92

(1)	The 10,000 options granted are performance based and vest on achievement of predefined milestones.

A summary of changes in our unvested restricted stock units for the three months ended March 31, 2016 is as follows:


	Number of RSUs			Weighted Average Grant Date Fair Value ($)
Outstanding at December 31, 2015		687,613			14.52
Granted(1)		277,210			3.84
Vested and exercised		(217,919	)		14.52
Cancelled		(34,875	)		13.68

Outstanding at March 31, 2016		712,029			10.44

(1)	Of the 277,210 restricted stock units issued, 73,171 restricted stock units vest and convert into shares of our common stock after one year from the date of grant. 204,039 restricted stock units are performance based and vest on achievement of predefined milestones.