Cash and Cash Equivalents and Short-term Investments (Tables)

12 Months Ended

Dec. 31, 2012

Cash And Cash Equivalents [Abstract]

Summary of Cash and Cash Equivalents and Short-Term Investments

A summary of cash and cash equivalents and short-term investments, classified as available-for-sale and carried at fair value is as follows (in thousands):

	Amortized Cost		Gross Unrealized Gain		Gross Unrealized (Loss)		Estimated Fair Value
December 31, 2012
Cash and cash equivalents	$	7,414	$	—	$	—	$	7,414
Short-term investments:
U.S. Treasury notes	$	203	$	—	$	—	$	203
Total	$	7,617	$	—	$	—	$	7,617
December 31, 2011
Cash and cash equivalents	$	2,148	$	—	$	—	$	2,148
Short-term investments:
Commercial paper	$	799	$	—	$	—	$	799
Certificates of deposit		730		—		—		730
U.S. Treasury notes		4,986		1		—		4,987
Total	$	6,515	$	1	$	—	$	6,516