4.	Common Stock Warrants

The following table summarizes the common stock warrant activity from December 31, 2013 through March 31, 2014:


	Shares		Weighted Average Exercise Price
Outstanding, December 31, 2013		6,035,229	$	3.63
Granted		—		—
Exercised		529,650		3.12
Forfeited/cancelled		—		—

Outstanding, March 31, 2014		5,505,579	$	3.67

Consultant Warrants

In January 2013, the Company entered into an agreement with a consultant that provided for the grant of warrants for the purchase of 5,000 shares of common stock at an exercise price of $2.65 per share. The following assumptions were used to value the warrants: an expected life of 3 years, volatility of 87%, risk free interest rate of 0.42% and zero dividends. The Company recognized an expense of $7,000 related to these warrants during the three months ended March 31, 2013.