Short-term Investments (Tables)

9 Months Ended

Jun. 30, 2018

Investments Debt And Equity Securities [Abstract]

Short-term Investments

	As of June 30, 2018 (in thousands)
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Short-term investments:
Corporate bonds	$	18,345	$	—	$	(86	)	$	18,259
Government bonds		8,777		—		(22	)		8,755
Total	$	27,122	$	—	$	(108	)	$	27,014

	As of September 30, 2017 (in thousands)
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Short-term investments:
Corporate bonds	$	22,829	$	—	$	(31	)	$	22,798
Government bonds		13,363		—		(24	)		13,339
Total	$	36,192	$	—	$	(55	)	$	36,137