	June 30, 2020
	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value
U.S. treasury securities	$	28,281	$	88	$	(1	)	$	28,368
Corporate bonds		70,781		360		(10	)		71,131
Asset-backed securities		24,333		142		—			24,475
	$	123,395	$	590	$	(11	)	$	123,974

	June 30, 2019
	Amortized cost		Gross unrealized gains		Fair value
U.S. treasury securities	$	64,683	$	75	$	64,758
Corporate bonds		4,787		—		4,787
Asset-backed securities		2,424		—		2,424
	$	71,894	$	75	$	71,969

The amortized cost and fair value amounts include accrued interest receivable of $0.5 million and $0.2 million at June 30, 2020 and 2019, respectively.

As of June 30, 2020, approximately 83% and 17% of the Company’s investments in marketable debt securities mature within one year and after one year through two years, respectively. As of June 30, 2019, 100% of the Company’s investments in marketable debt securities matured within one year.

The following table presents gross unrealized losses and fair values for those investments that were in an unrealized loss position as of June 30, 2020 (in thousands):

	June 30, 2020
	Fair value		Unrealized losses
U.S. treasury securities	$	2,798	$	(1	)
Corporate bonds		9,258		(10	)
Total	$	12,056	$	(11	)

Investments with unrealized losses have been in a continuous unrealized loss position for less than 12 months. The Company does not intend to sell the investments and it is not likely that the Company will be required to sell the investments before recovery of their amortized cost bases, which may be at maturity. Therefore, the Company does not consider those unrealized investment losses as other-than-temporary impairment of the investments. There have been no significant realized gains or losses on the short-term investments during the years ended June 30, 2020, 2019 and 2018.