Fair Value Measurements (Tables)

12 Months Ended

Sep. 30, 2012

Fair Value Disclosures [Abstract]

Fair Value of Assets Measured on Recurring Basis

The following tables provide information by level for financial assets that are measured at fair value on a recurring basis (in thousands):

			Fair Value Measurements at September 30, 2012 using:
	Total carrying value at September 30, 2012		Quoted price in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Cash equivalents:
Money market	$	28,355	$	28,355	$	—	$	—
Available-for-sale marketable securities:
Corporate bonds	41,317		—		41,317		—
Commercial paper	2,000		—		2,000		—
Certificates of deposit	7,258		—		7,258		—
Government municipal bonds	9,813		—		9,813		—
Total cash equivalents and marketable securities measured at fair value	$	88,743	$	28,355	$	60,388	$	—

			Fair Value Measurements at September 30, 2011 using:
	Total carrying value at September 30, 2011		Quoted price in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Cash equivalents:
Money market	$	30,474	$	30,474	$	—	$	—
Available-for-sale marketable securities:
Corporate bonds	24,171		—		24,171		—
Commercial paper	4,995		—		4,995		—
Certificates of deposit	8,766		—		8,766		—
Government municipal bonds	15,195		—		15,195		—
Total cash equivalents and marketable securities measured at fair value	$	83,601	$	30,474	$	53,127	$	—