Investments

6 Months Ended

Jun. 30, 2011

Investments [Abstract]

Investments

Note 4. Investments

We have cash investment policies that limit investments to investment grade securities. At June 30, 2011 and December 31, 2010, all of our investments were classified as available-for-sale and carried at fair value. Our investments in corporate debt are guaranteed by the FDIC or foreign governments. At June 30, 2011, all of our investments had maturity dates of less than twenty-four months.

The amortized cost and fair value of our investments, with gross unrealized gains and losses, were as follows:

At June 30, 2011

			Gross		Gross
	Amortized		Unrealized		Unrealized			Aggregate
	Cost Basis		Gains		Losses			Fair Value
Short-term investments:
U.S. government agency debt	$	49,806,325	$	6,982	$	(22,236	)	$	49,791,071
Corporate debt		15,182,732		24,329		—			15,207,061
Certificates of deposit		15,000,000		—		—			15,000,000
Total short-term investments	$	79,989,057	$	31,311	$	(22,236	)	$	79,998,132

     At December 31, 2010

			Gross		Gross
	Amortized		Unrealized		Unrealized			Aggregate
	Cost Basis		Gains		Losses			Fair Value
Short-term investments:
Corporate debt	$	21,294,673	$	35,437	$	—		$	21,330,110
Total short-term investments	$	21,294,673	$	35,437	$	—		$	21,330,110
Long-term investments:
U.S. government agency debt	$	4,006,714	$	—	$	(1,055	)	$	4,005,659
Total long-term investments	$	4,006,714	$	—	$	(1,055	)	$	4,005,659

For the three and six months ended June 30, 2011 and 2010 we did not have any realized gains or losses on our investments.