Short-Term Investments (Tables)

6 Months Ended

Jun. 30, 2014

Investments Debt And Equity Securities [Abstract]

Short-Term Investments Available-for-Sale Securities

Short-term investments consisted of available-for-sale securities as follows (in thousands):

Type of security as of June 30, 2014	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value
U.S. government-related debt securities	$	1,534	$	1	$	—		$	1,535
Corporate debt securities		53,562		15		(9	)		53,568
Asset-backed securities		3,300		1		(1	)		3,300
Total available-for-sale securities	$	58,396	$	17	$	(10	)	$	58,403
Type of security as of December 31, 2013	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value
U.S. government-related debt securities	$	1,565	$	1	$	—		$	1,566
Corporate debt securities		31,128		24		(3	)		31,149
Total available-for-sale securities	$	32,693	$	25	$	(3	)	$	32,715

Fair Values of Available-for-Sale Securities by Contractual Maturity

The fair values of available-for-sale securities by contractual maturity were as follows (in thousands):

Contractual maturity	June 30, 2014		December 31, 2013
Maturing in one year or less	$	52,082	$	26,725
Maturing in one to three years		6,321		5,990
Total available-for-sale securities	$	58,403	$	32,715