Available-for-Sale Investments

6 Months Ended

Jun. 30, 2011

Available-for-Sale Investments

Available-for-Sale Investments

7. Available-for-Sale Investments

The following tables summarize the available-for-sale securities held at June 30, 2011 and December 31, 2010 (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
June 30, 2011:
U.S. government-sponsored securities	$	45,181	$	10	$	(20	)	$	45,171
U.S. Treasury securities	107,679		62		—			107,741
Total	$	152,860	$	72	$	(20	)	$	152,912

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
December 31, 2010:
U.S. government-sponsored securities	$	87,503	$	3	$	(19	)	$	87,487
U.S. Treasury securities	116,200		24		(5		)	116,219
Total	$	203,703	$	27	$	(24	)	$	203,706

The contractual maturities of all securities held at June 30, 2011 was one year or less. There were five investments in an unrealized loss position at June 30, 2011, none of which had been in an unrealized loss position for more than twelve months. The aggregate fair value of these securities was approximately $14.7 million. The Company reviews its investments for other-than-temporary impairment whenever the fair value of an investment is less than amortized cost and evidence indicates that an investment’s carrying amount is not recoverable within a reasonable period of time. To determine whether an impairment is other-than-temporary, the Company considers whether it has the ability and intent to hold the investment until a market price recovery and considers whether evidence indicating the cost of the investment is recoverable outweighs evidence to the contrary. The Company did not hold any securities with an other-than-temporary impairment at June 30, 2011.

Gross realized gains and losses on the sales of investments have not been material to the Company’s consolidated results of operations.