Shared-Based Payments (Tables)

9 Months Ended

Sep. 30, 2013

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Stock-Based Compensation Expense

The following stock-based compensation amounts were recognized for the periods indicated:


	Three Months Ended September 30				Nine Months Ended September 30
	2013		2012		2013		2012
Research and development	$	111,888	$	117,952	$	284,281	$	353,856
General and administrative		24,048		91,647		109,280		274,940

Total stock-based compensation expense	$	135,936	$	209,599	$	393,561	$	628,796

Schedule of Fair Value Option Award Estimated on the Date of Grant Using the Black-Scholes Option-Pricing Model

The fair value of each option award is estimated on the date of grant using the Black-Scholes option-pricing model using the assumptions in the following table:


	Nine Months Ended September 30,
	2013	2012
Expected dividend yield	0%	0%
Expected volatility	53% - 58%	51%
Risk-free interest rate	1.24% - 2.05%	1.18%
Expected average life of options	7 years	7 years
Fair market value of common stock at:	$1.50 - $7.51	$1.50
Expected forfeiture rate	5.06%	5.57%

Schedule of Stock Option Activity

The following table summarizes stock option activity under the Plan during the period then ended:


	Number of Options			Weighted- Average Exercise Price		Weighted- Average Contractual Term (in Years)
Outstanding, December 31, 2012		3,249,702			0.94		7.3
Granted		687,183			3.19		7.0
Exercised		(1,025,933	)		0.75
Forfeited or expired		(33,949	)		1.13

Outstanding, September 30, 2013		2,877,003			1.50		7.2

September 30, 2013:
Exercisable		1,855,178			0.94
Vested and Expected to Vest		918,600			2.44