Short-Term Investments (Tables)

12 Months Ended

Dec. 31, 2013

Investments, Debt and Equity Securities [Abstract]

Summary of Short-Term Investments

The following table summarizes the Company’s short-term investments (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
As of December 31, 2013
State, municipal and local government agencies bonds	$	40,426	$	38	$	(15	)	$	40,449
Corporate bonds	33,483		20		(7		)	33,496
Commercial paper	2,299		—		—			2,299
U.S. federal government bonds	4,004		4		—			4,008
Total short-term investments	$	80,212	$	62	$	(22	)	$	80,252
As of December 31, 2012
Certificates of deposit	$	1,603	$	—	$	—		$	1,603
State, municipal and local government agencies bonds	59,009		45		(4		)	59,050
Corporate bonds	31,568		4		(10		)	31,562
Commercial paper	10,287		1		—			10,288
U.S. federal government bonds	2,003		—		—			2,003
Total short-term investments	$	104,470	$	50	$	(14	)	$	104,506

Maturities of Short-Term Investments

The following table summarizes the maturities of the Company’s short-term investments (in thousands):

	December 31,
	2013		2012
Less than one year	$	55,278	$	76,779
Due in 1 - 2 years	24,974		27,727
Total short-term investments	$	80,252	$	104,506