FAIR VALUE (Tables)

6 Months Ended

Jun. 30, 2015

Fair Value Disclosures [Abstract]

Summary of fair value hierarchy for its financial assets and liabilities measured at fair value on a recurring basis

The following table represents the Company's fair value hierarchy for its financial assets (cash, cash equivalents and investments) measured at fair value on a recurring basis as of June 30, 2015 (in thousands):

	Level 1		Level 2		Level 3		Total
Assets:
Cash	$	333,160	$	—	$	—	$	333,160
Money market funds	5,386		—		—		5,386
Commercial paper	13,235		—		—		13,235
Auction rate securities	—		—		16,049		16,049
Total assets measured at fair value	$	351,781	$	—	$	16,049	$	367,830

The following table represents the Company's fair value hierarchy for its financial assets (cash, cash equivalents and investments) measured at fair value on a recurring basis as of December 31, 2014 (in thousands):

	Level 1		Level 2		Level 3		Total
Assets:
Cash	$	160,275	$	—	$	—	$	160,275
Money market funds	310,482		—		—		310,482
Commercial paper	56,255		—		—		56,255
Auction rate securities	—		—		17,151		17,151
Total assets measured at fair value	$	527,012	$	—	$	17,151	$	544,163

Summary of changes in the fair value of the company's level 3 assets

The following tables summarize changes in fair value of the Company’s Level 3 assets for the three and six months ended June 30, 2015 and 2014 (in thousands):

	Three Months Ended June 30,						Six Months Ended June 30,
	2015			2014			2015			2014
Balance at beginning of period	$	16,669		$	22,168		$	17,151		$	21,990
Decrease in unrealized loss included in accumulated other comprehensive loss	80			21			248			199
Settlements	(700		)	(550		)	(1,350		)	(550		)
Balance at end of period	$	16,049		$	21,639		$	16,049		$	21,639

The following table summarizes changes in fair value of the Company’s Level 3 assets from December 31, 2007 to June 30, 2015 (in thousands):

	Auction Rate Securities
Balance at December 31, 2007	$	53,975
Increase in unrealized loss included in accumulated other comprehensive loss	(3,710		)
Settlements	(20,925		)
Balance at December 31, 2008	29,340
Decrease in unrealized loss included in accumulated other comprehensive loss	684
Settlements	(300		)
Balance at December 31, 2009	29,724
Decrease in unrealized loss included in accumulated other comprehensive loss	40
Settlements	(575		)
Balance at December 31, 2010	29,189
Decrease in unrealized loss included in accumulated other comprehensive loss	245
Settlements	(4,850		)
Balance at December 31, 2011	24,584
Auction rate securities upon acquisition	442
Decrease in unrealized loss included in accumulated other comprehensive loss	836
Settlements	(4,200		)
Balance at December 31, 2012	21,662
Decrease in unrealized loss included in accumulated other comprehensive loss	378
Settlements	(50		)
Balance at December 31, 2013	21,990
Decrease in unrealized loss included in accumulated other comprehensive loss	836
Settlements	(5,675		)
Balance at December 31, 2014	17,151
Decrease in unrealized loss included in accumulated other comprehensive loss	248
Settlements	(1,350		)
Balance at June 30, 2015	$	16,049