Balance Sheet Accounts (Schedule of Unrealized Losses and Fair Values by Investment Category and Time in Continuous Unrealized Loss Position) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 Months, Fair Value	$ 5,111
Less than 12 Months, Unrealized Losses	(6)
12 Months or More, Fair Value	0
12 Months or More, Unrealized Losses	0
Fair Value, Total	5,111
Unrealized Losses, Total	(6)
U.S. Corporate Debt Securities
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 Months, Fair Value	5,111
Less than 12 Months, Unrealized Losses	(6)
12 Months or More, Fair Value	0
12 Months or More, Unrealized Losses	0
Fair Value, Total	5,111
Unrealized Losses, Total	(6)
U.S. Government Agency Securities
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 Months, Fair Value	0
Less than 12 Months, Unrealized Losses	0
12 Months or More, Fair Value	0
12 Months or More, Unrealized Losses	0
Fair Value, Total	0
Unrealized Losses, Total	0
U.S. Municipal Bonds
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 Months, Fair Value	0
Less than 12 Months, Unrealized Losses	0
12 Months or More, Fair Value	0
12 Months or More, Unrealized Losses	0
Fair Value, Total	0
Unrealized Losses, Total	$ 0