MARKETABLE SECURITIES

9 Months Ended

Mar. 31, 2019

Investments, Debt and Equity Securities [Abstract]

MARKETABLE SECURITIES

MARKETABLE SECURITIES

Marketable securities consisted of the following as of March 31, 2019 and June 30, 2018 (in thousands):

	March 31, 2019
			Gross		Gross
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
Short-term available-for-sale securities:
U.S. treasury securities	$	123,149	$	—	$	(3	)	$	123,146
Commercial paper	110,478		—		—			110,478
Corporate bonds	61,713		60		—			61,773
Asset-backed securities	30,727		32		—			30,759
Mutual fund securities	296		—		—			296
	326,363		92		(3		)	326,452
Long-term available-for-sale securities:
Corporate bonds	32,421		44		—			32,465
Asset-backed securities	22,721		32		—			22,753
Mutual fund securities	790		—		—			790
	55,932		76		—			56,008
Total	$	382,295	$	168	$	(3	)	$	382,460

	June 30, 2018
			Gross		Gross
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
Short-term available-for-sale securities:
U.S. treasury securities	$	297,965	$	—	$	(461	)	$	297,504
Mutual fund securities	235		—		—			235
	298,200		—		(461		)	297,739
Long-term available-for-sale securities:
Mutual fund securities	919		—		—			919
	919		—		—			919
Total	$	299,119	$	—	$	(461	)	$	298,658

The mutual fund securities shown in the above tables are securities held under the Array BioPharma Inc. Deferred Compensation Plan.

As of March 31, 2019, the amortized cost and estimated fair value of available-for-sale debt securities by contractual maturity were as follows (in thousands):

	Amortized		Fair
	Cost		Value
Due in one year or less	$	326,067	$	326,156
Due in one to three years	55,142		55,218
Total	$	381,209	$	381,374