Fair Value of Financial Instruments (Tables)

6 Months Ended

Mar. 31, 2018

Fair Value Disclosures [Abstract]

Fair Value Measurement of Company's Short-term Investments and Derivative Instruments

The fair value measurement of the Company’s short-term investments and derivative instruments was determined using the following inputs (in thousands):

	As of March 31, 2018
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable (Level 2)			Significant Unobservable (Level 3)		Totals
Short-term investments:
Corporate bonds	$	17,394	$	—		$	—	$	17,394
Government bonds		9,068		—			—		9,068
Foreign currency forward contracts		—		(55	)		—		(55	)
Total	$	26,462	$	(55	)	$	—	$	26,407

	As of September 30, 2017
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable (Level 2)		Significant Unobservable (Level 3)		Totals
Short-term investments:
Corporate bonds	$	22,798	$	—	$	—	$	22,798
Government bonds		13,339		—		—	$	13,339
Total	$	36,137	$	—	$	—	$	36,137