Common Stock Warrants (Tables)

6 Months Ended

Jun. 30, 2012

Common Stock Warrants [Abstract]

Warrants issued to members of board of directors

In June 2012, 550,000 warrants previously issued in June 2007 to then members of our board of directors and 348,417 warrants issued in June 2007 as part of a common stock offering were exercised or expired as follows:

Type of Exercise	Warrant Shares		Exercise Price / Share		Cash Received		Common Stock Shares Issued
For cash		175,000	$	1.50	$	262,500		175,000
Cashless net exercise		575,000	$	1.50	$	—		64,495
Expired unexercised		98,417	$	1.50	$	—		—

Warrant Activity

Warrant activity for the six months ended June 30, 2012 is summarized as follows:

	Shares			Weighted Average Exercise Price
Warrants outstanding, December 31, 2011		2,156,750		$	1.34
Granted		200,000			1.43
Exercised		(900,000	)		1.50
Expired		(98,417	)		1.50
Cancelled		—			—
Warrants outstanding, June 30, 2012		1,358,333			1.24