Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2014

Fair Value Disclosures [Abstract]

Schedule of assets measured at fair value on a recurring basis

The Company’s assets that are measured at fair value on a recurring basis, at March 31, 2014 and December 31, 2013, consist of the following:

			Fair Value Measurements at Reporting Date Using
At March 31, 2014	Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)
Available-for-sale marketable securities:
U.S. government and government agency obligations	$	78,265	—		$	78,265
Corporate bonds	579,628		—		579,628
Municipal bonds	43,401		—		43,401
International government agency obligations	8,217		—		8,217
Certificates of deposit	7,918		—		7,918
Equity securities	3,535		$	3,535	—
	$	720,964	$	3,535	$	717,429
At December 31, 2013
Available-for-sale marketable securities:
U.S. government and government agency obligations	$	107,521	—		$	107,521
Corporate bonds	369,193		—		369,193
Commercial paper	23,944		—		23,944
Municipal bonds	36,921		—		36,921
International government agency obligations	2,008		—		2,008
Certificates of deposit	7,514		—		7,514
Equity securities	1,166		$	1,166	—
	$	548,267	$	1,166	$	547,101