Short-term Investments (Tables)

9 Months Ended

Sep. 30, 2012

Summary of Short-Term Investments

The following is a summary of our short-term investments (in thousands):

	September 30, 2012
	(Unaudited)
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Available-for-sale securities:
Commercial paper	$	36,659	$	1	$	(12	)	$	36,648
Corporate notes and bonds		100,806		30		(22	)		100,814
U.S. government agency securities		2,022		1		—			2,023
Total available-for-sale securities	$	139,487	$	32	$	(34	)	$	139,485

Fair Values and Gross Unrealized Losses of Available-for-Sale Securities Aggregated by Investment Category

The following table shows the fair values and the gross unrealized losses of these available-for-sale securities aggregated by investment category (in thousands):

	September 30, 2012
	(Unaudited)
	Fair Value		Gross Unrealized Losses
Commercial paper	$	34,908	$	(12	)
Corporate notes and bonds		65,782		(22	)
Total	$	100,690	$	(34	)