Short-term Investments (Tables)

12 Months Ended

Sep. 30, 2012

Short-term Investments [Abstract]

Short-term investments

	As of September 30, 2012 (in thousands)
	Amortized Cost		Unrealized Gains		Unrealized Losses		Estimated Fair Value
Short-term investments:
Corporate	$	11,072	$	37	$	—	$	11,109
Government		8,842		9		—		8,851
Total	$	19,914	$	46	$	—	$	19,960

	As of September 30, 2011 (in thousands)
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Short-term investments:
Corporate	$	3,890	$	—	$	(18	)	$	3,872
Government		1,054		—		—			1,054
Total	$	4,944	$	—	$	(18	)	$	4,926