Marketable Securities (Tables)

9 Months Ended

Apr. 30, 2018

Marketable Securities [Abstract]

Summary of marketable securities

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
	(in thousands)
Available-for-sale securities:
April 30, 2018:
Certificates of deposit*	$	5,649	$	—	$	—		$	5,649
Equity		78		27		—			105
U.S. Treasury notes		1,690		—		(1	)		1,689
Municipal bonds		3,132		—		(5	)		3,127
Total	$	10,549	$	27	$	(6	)	$	10,570
July 31, 2017:
Certificates of deposit*	$	29,011	$	1	$	(7	)	$	29,005
Federal Government Sponsored Enterprise notes		3,992		—		(14	)		3,978
International agency notes		291		—		—			291
Mutual funds		5,353		77		—			5,430
Corporate bonds		4,643		—		—			4,643
Equity		74		—		(26	)		48
U.S. Treasury notes		6,673		—		—			6,673
Municipal bonds		8,201		4		(1	)		8,204
Total	$	58,238	$	82	$	(48	)	$	58,272

* Each of the Company’s certificates of deposit has a CUSIP, was purchased in the secondary market through a broker, and may be sold in the secondary market.

Summary of available-for-sale debt securities

	Fair Value
	(in thousands)
Within one year	$	10,161
After one year through five years		304
After five years through ten years		—
After ten years		—
Total	$	10,465

Summary of available-for-sale securities, unrealized loss position

	Unrealized Losses		Fair Value
	(in thousands)
April 30, 2018:
U.S. Treasury notes	$	1	$	1,689
Municipal bonds		5		3,127
Total	$	6	$	4,816
July 31, 2017:
Certificates of deposit	$	7	$	12,155
Federal Government Sponsored Enterprise notes		14		3,529
Equity		26		48
Municipal bonds		1		3,349
Total	$	48	$	19,081

Summary of available-for-sale securities, continuous unrealized loss position

	Unrealized Losses		Fair Value
	(in thousands)
Municipal bonds	$	1	$	343