Short-term Investments

6 Months Ended

Mar. 31, 2018

Investments Debt And Equity Securities [Abstract]

Short-term Investments

2.   Short-term Investments

	As of March 31, 2018 (in thousands)
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
Short-term investments:
Corporate bonds	$	17,503	$	—	$	(109	)	$	17,394
Government bonds		9,103		—		(35	)		9,068
Total	$	26,606	$	—	$	(144	)	$	26,462

	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

  The Company’s short-term investments have contractual maturities ranging from April 2018 to January 2020.