Derivative Financial Instruments (Tables)

3 Months Ended

Dec. 31, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Summary of Outstanding Foreign Currency Forward Contracts

The following tables summarize our outstanding foreign currency forward contracts, by currency, at December 31, 2018 and September 30, 2018:

	December 31, 2018
	Contract Amount				Fair Value
	Foreign Currency		US$		US$
	(In thousands)
Sell foreign currency:
Euro (EUR)	EUR	10,750	$	12,312	$	—
Buy foreign currency:
British pound (GBP)	GBP	8,592	$	11,000	$	—
Singapore dollar (SGD)	SGD	7,211	$	5,300	$	—

	September 30, 2018
	Contract Amount				Fair Value
	Foreign Currency		US$		US$
	(In thousands)
Sell foreign currency:
Euro (EUR)	EUR	9,000	$	10,372	$	—
Buy foreign currency:
British pound (GBP)	GBP	8,598	$	11,200	$	—
Singapore dollar (SGD)	SGD	9,580	$	7,000	$	—

Losses on Derivative Financial Instruments

Gains (losses) on derivative financial instruments are recorded in our condensed consolidated statements of income and comprehensive income as a component of other income, net, and consisted of the following: 

	Quarter Ended December 31,
	2018			2017
	(In thousands)
Gains (losses) on foreign currency forward contracts	$	(404	)	$	194