Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2014

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Estimated Fair Value of Stock Option Award

The estimated fair value of each stock option award granted was determined on the date of grant using the Black-Scholes option-pricing valuation model with the following weighted-average assumptions for option grants during the three and nine months ended September 30, 2014.

	Three Months Ended			Nine Months Ended
	September 30,			September 30,
	2014	2013		2014		2013
Common Stock Options
Risk free interest rate	—		1.75%	1.66-1.77%			1.75%
Expected option term	—	6 years		5.5-6.0 years		6 years
Expected volatility of common stock	—		70.8%	71.06-73.21%			70.8%
Expected dividend yield	—		0.00%		0.00%		0.00%

Summary of Estimated Fair Value of Employee Stock Purchase Plan Award

The estimated fair value of each employee stock purchase plan award was determined on the date of grant using the Black-Scholes option-pricing valuation model with the following weighted-average assumptions for the employee stock purchase plan during the three and nine months ended September 30, 2014. The employee stock purchase plan did not become active until March 2014.

	Three Months Ended			Nine Months Ended
	September 30,			September 30,
	2014		2013	2014		2013
Employee Stock Purchase Plan
Risk free interest rate		0.05%	—	0.05-0.08%		—
Expected option term	6 months		—	6 months		—
Expected volatility of common stock		69.32%	—	69.32-73.21%		—
Expected dividend yield		0.00%	—		0.00%	—

Summary of Recognized Non-Cash Stock-Based Compensation Expense

The Company recognized non-cash stock-based compensation expense to employees and directors in its research and development and its general and administrative functions as follows:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2014		2013		2014		2013
Research and development	$	105,145	$	313		302,569	$	4,377
General and administrative		198,816		7,316		489,912		9,504
Total stock-based compensation expense	$	303,961	$	7,629		792,481	$	13,881