Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2014

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

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


	Three months ended March 31,
	2014			2013
Research and development expense	$	186,293		$	343,711
Selling, general and administrative expense		334,813			342,871

Total stock-based compensation	$	521,106		$	686,582

Effect on basic and diluted net loss per share	$	(0.01	)	$	(0.02	)

Stock Option Activity

A summary of our stock option activity for the three months ended March 31, 2014 is as follows:


	Number of options			Weighted-average exercise price ($) per share
Outstanding options at December 31, 2013		428,258			19.97
Granted		—			—
Exercised		—			—
Cancelled		(46,407	)		35.81

Outstanding options at March 31, 2014		381,851			18.05

Summary of Changes in Unvested Options

A summary of changes in unvested options for the three months ended March 31, 2014 is as follows:


	Number of options			Weighted-average exercise price ($) per share		Weighted-average grant date fair value ($) per option
Unvested options at December 31, 2013		18,466			10.17		8.11
Granted		—			—		—
Vested		(9,283	)		10.45		8.33
Cancelled		(1,591	)		8.13		6.12

Unvested options at March 31, 2014		7,592			10.27		8.26

Summary of Changes in Unvested Restricted Stock Units

A summary of changes in our restricted stock units for the three months ended March 31, 2014 is as follows:


	Number of RSUs			Weighted Average Grant Date Fair Value ($)
Outstanding at December 31, 2013		3,326,282			1.68
Granted(1)		594,874			1.34
Vested and exercised		(376,216	)		1.10
Cancelled		(400,000	)		1.84

Outstanding at March 31, 2014		3,144,940			1.66

(1)

218,874 of these restricted stock units vest and convert into shares of our common stock after one year from the date of grant. 376,000 of these restricted stock units will vest and convert into shares of our common stock over a four year period from the date of grant; one-fourth of the award will vest on each grant date anniversary following the grant.