Basis of Presentation and Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2012

Assumptions Used to Estimate Fair Value of Option Granted

The fair value of each option granted during the nine months ended September 30, 2012 and 2011 was estimated as of the grant date using the Black-Scholes option pricing model with the following assumptions:

	Nine months ended September 30, 2012	Nine months ended September 30, 2011
Risk-free interest rate	1.18 – 1.49%	2.29 – 2.81%
Expected life of options (in years)	7.5	7.5
Expected stock price volatility	108%	111%

Summary of Activity of 2003 Stock Plan and 2006 Equity Incentive Plan

A summary of the activity for our 2003 Stock Plan and 2006 Equity Incentive Plan is presented below for the nine months ended September 30, 2012:

	Options Outstanding								Options Exercisable
	Number of Shares			Price per Share Range	Weighted Average Exercise Price		Aggregate Intrinsic Value (1)		Number of Shares		Weighted Average Exercise Price		Aggregate Intrinsic Value (1)
Balance, December 31, 2011		4,641,039		$0.35 – $ 6.74	$	2.23	$	1,509,270		3,206,994	$	2.23	$	1,258,740
Granted		896,381		$1.40 – 1.75	$	1.67
Exercised		(179,273	)	$0.35 – 0.82	$	0.36
Canceled		(60,636	)	$0.65 – 5.50	$	1.91
Balance, September 30, 2012		5,297,511		$0.35 – 6.74	$	2.20	$	1,177,163		3,575,182	$	2.37	$	1,016,110

(1) The intrinsic value of an option represents the amount by which the market value of the stock exceeds the exercise price of the option of in-the-money options only. The aggregate intrinsic value is based on the closing price of our Common Stock on the NASDAQ Capital Market, as applicable, on the respective dates.