Fair Value of Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2014

Fair Value of Financial Instruments [Abstract]

Financial assets measured and recognized at fair value on a recurring basis and classified under appropriate level of fair value hierarchy

As of March 31, 2014, financial assets measured and recognized at fair value on a recurring basis and classified under the appropriate level of the fair value hierarchy as described above were as follows (in thousands):

March 31, 2014	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	5,736	$	—	$	—	$	5,736
Commercial paper		—		2,250		—		2,250
Marketable investments:
Available-for-sale securities		—		73,079		—		73,079
Total assets at fair value	$	5,736	$	75,329	$	—	$	81,065

As of December 31, 2013, financial assets measured and recognized at fair value on a recurring basis and classified under the appropriate level of the fair value hierarchy as described above was as follows (in thousands):

December 31, 2013	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	9,926	$	—	$	—	$	9,926
Commercial paper		—		2,500		—		2,500
Marketable investments:
Available-for-sale securities		—		66,831		—		66,831
Total assets at fair value	$	9,926	$	69,331	$	—	$	79,257