Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2014

Fair Value Measurements [Abstract]

Fair Value Hierarchy

The following table represents the Company's fair value hierarchy for its financial assets and liabilities measured at fair value on a recurring basis (in thousands):

	Fair Value at June 30, 2014						Fair Value at December 31, 2013
Assets	Level 1		Level 2		Level 3		Level 1		Level 2		Level 3
Auction rate security	$	―	$	―	$	—	$	1,790	$	―	$	—
Money market funds		73,069		―		—		100,049		—		—
Government-backed  security		—		18,000		—		―		—		—
Asset-backed securities		—		42,483		—		—		—		—
Corporate debt securities		—		72,467		—		—		26,978		—
Total cash equivalents and investments	$	73,069	$	132,950	$	—	$	101,839	$	26,978	$	—