Short-Term Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2014

Investments, Debt and Equity Securities [Abstract]

Summary of Short-Term Marketable Securities

The following is a summary of short-term marketable securities classified as available-for-sale (in thousands):

December 31, 2014	Amortized Cost		Unrealized Gain		Unrealized Loss		Market Value
U.S. treasuries	$	5,558	$	—	$	1	$	5,557
Government-sponsored enterprise securities		7,499		—		6		7,493
Corporate bonds		2,025		—		5		2,020
Certificates of deposit		8,429		—		—		8,429
	$	23,511	$	—	$	12	$	23,499

December 31, 2013	Amortized Cost		Unrealized Gain		Unrealized Loss		Market Value
U.S. treasuries	$	1,500	$	3	$	—	$	1 ,503
Government-sponsored enterprise securities		4,500		—		—		4,500
Corporate bonds		4,853		—		—		4,853
Certificates of deposit		685		—		—		685
	$	11,538	$	3	$	—	$	11,541