Marketable Securities

9 Months Ended

Feb. 28, 2018

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

MARKETABLE SECURITIES

Marketable securities, which can be government agency bonds, auction rate investments or corporate commercial paper, are classified as “available-for-sale securities” and are reported at fair value, with unrealized gains and losses excluded from operations and reported as accumulated other comprehensive income (loss), net of the related tax effects, in stockholders’ equity. Cost is determined using the specific identification method. We hold an investment in an auction rate security that is high credit quality and generally achieved with municipal bond insurance. Sell orders for any security traded through an auction process could exceed bids and, in such cases, the auction fails and we may be unable to liquidate our position in the security in the near term. We have not participated in any recent auctions. As of February 28, 2018 and May 31, 2017, we had $1.3 million and $1.2 million, respectively, in investments in one auction rate security. The authorities are current in their interest payments on the security. The auction rate security will mature in 2029.

As of February 28, 2018 and May 31, 2017, marketable securities consisted of the following (in thousands of dollars):

	February 28, 2018
(in thousands)	Amortized cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Available-for-sale securities:
Government agency obligations	$	1,350	$	—	$	(69	)	$	1,281
	$	1,350	$	—	$	(69	)	$	1,281

	May 31, 2017
(in thousands)	Amortized cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Available-for-sale securities:
Government agency obligations	$	1,350	$	—	$	(135	)	$	1,215
	$	1,350	$	—	$	(135	)	$	1,215