Equity (Schedule of Stock-based Compensation Expense - by Expense Category) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
Expense:
Stock-based compensation expense	$ 1,051	$ 2,542	$ 2,133	$ 4,722
Cost of revenue
Expense:
Stock-based compensation expense	290	593	605	1,069
Selling, general and administrative
Expense:
Stock-based compensation expense	459	1,233	841	2,246
Research and development
Expense:
Stock-based compensation expense	$ 302	$ 716	$ 687	$ 1,407