v2.4.0.6
Stockholders' Equity (Tables)
3 Months Ended
Mar. 31, 2013
Stockholders' Equity Attributable To Parent [Abstract]  
Assumptions Used in Black-Scholes Option-Pricing Model

The Company records compensation expense associated with stock options and other forms of equity compensation using the Black-Scholes option-pricing model and the following assumptions:

 

   

Three Months Ended

March 31, 2013

 

Three Months Ended

March 31, 2012

 
Expected Term   5 years   5 years  
Volatility   118% - 131%   113% - 114%  
Dividend yield   0.0%   0.0%  
Risk-free interest rate   0.81% - 1.96%   0.86% - 1.22%
Summary of Option Activity under Plan and Related Information

A summary of the Company’s stock options activity and related information is as follows:

 

    Three Months Ended
March 31, 2013
    Three Months Ended
March 31, 2012
 
    Shares     Weighted
Average
Exercise
Price
    Shares     Weighted
Average
Exercise
Price
 
Outstanding at beginning of period     2,135,630     $ 1.26       1,236,342     $ 2.47  
Forfeited     (237,333 )   $ 1.61       (19,220 )   $ 1.89  
Granted     1,400,000     $ 0.90       330,000     $ 0.40  
Outstanding at end of period     3,298,297     $ 1.08       1,547,122     $ 2.03  
Expected to vest     1,476,200     $ 0.78       402,698     $ 2.03  
Options exercisable     878,297     $ 1.91       875,958     $ 2.60  
Weighted-average fair value of options granted during the period           $ 0.77             $ 0.32  
Summary of warrants outstanding

The following table is the summary of warrants outstanding at March 31, 2013:

 

    Number of
Warrants
    Exercise
Price
    Expiration
Date
Issued to co-placement agents in connection with previous convertible note financings     18,250       7.84     10/29/2014
Issued in connection with 2009 private placement     503,034       3.4375     10/29/2014
Issued in connection with IPO     4,043,569       3.4375     3/24/2015
Issued to IPO underwriters that, if exercised, would result in the issuance of an additional 4,812 shares of common stock and warrants to purchase an additional 2,406 shares of common stock     4,812       3.90     3/24/2015
Issued in connection with September 20, 2012 private placement of convertible notes     2,125,000       0.40     9/20/2017
Issued to placement agent in connection with September 20, 2012 private placement of convertible notes     212,500       0.40     9/20/2017
Issued in connection with November 13, 2012 private placement of convertible notes     1,185,000       0.40     11/13/2017
Issued to placement agent in connection with November 13, 2012 private placement of convertible notes     118,500       0.40     11/13/2017
Issued in connection with February 2013 private placement     400,000       1.50     2/19/2018
Total warrants outstanding at March 31, 2013     8,610,665