Balance Sheet Account Details (Details 1) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012
Available-for-sale securities:
Fair Value	$ 100,690
Gross Unrealized Losses	(34)
Commercial paper [Member]
Available-for-sale securities:
Fair Value	34,908
Gross Unrealized Losses	(12)
Corporate notes and bonds [Member]
Available-for-sale securities:
Fair Value	65,782
Gross Unrealized Losses	$ (22)