Marketable Securities (Tables)

6 Months Ended

Jun. 30, 2013

Investments Debt And Equity Securities [Abstract]

Marketable Securities

Marketable securities at June 30, 2013 consist of the following (in thousands):

	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Certificates of deposit	$	5,200	$	—	$	(5	)	$	5,195
U.S. Treasuries		16,598		1		—			16,599
	$	21,798	$	1	$	(5	)	$	21,794

Marketable securities at December 31, 2012 consist of the following (in thousands):

	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Certificates of deposit	$	7,386	$	—	$	(2	)	$	7,384
U.S. Treasuries		29,294		1		—			29,295
	$	36,680	$	1	$	(2	)	$	36,679