Investments (Tables)

12 Months Ended

Apr. 30, 2019

Investments

Schedule of investments

	April 30,
	2019		2018
	(In thousands)
Short-term investments:
Held-to-maturity securities:
Municipal securities	$	5,332	$	35,344
U.S. government securities		63,205		31,620
Corporate bonds		81,950		46,685
Total held-to-maturity and short-term investments	$	150,487	$	113,649
Long-term investments:
Held-to-maturity securities:
Municipal securities	$	—	$	2,046
U.S. government securities		7,404		27,356
Corporate bonds		1,982		9,112
Total held-to-maturity investments		9,386		38,514
Available-for-sale securities:
Auction rate securities		—		2,142
Total available-for-sale investments		—		2,142
Total long-term investments	$	9,386	$	40,656

Held to maturity securities

Investments

Schedule of amortized cost, gross unrealized gains, gross unrealized losses, and estimated fair value of held-to-maturity investments

The amortized cost, gross unrealized losses, and estimated fair value of the held‑to‑maturity investments as of April 30, are as follows (in thousands):

	April 30, 2019								April 30, 2018
			Gross		Gross						Gross		Gross
	Amortized		Unrealized		Unrealized		Fair		Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value		Cost		Gains		Losses		Value
Municipal securities	$	5,332	$	2	$	(1)	$	5,333	$	37,390	$	9	$	(36)	$	37,363
U.S. government securities		70,609		78		(52)		70,635		58,976		—		(367)		58,609
Corporate bonds		83,932		20		(5)		83,947		55,797		2		(71)		55,728
Total held-to-maturity investments	$	159,873	$	100	$	(58)	$	159,915	$	152,163	$	11	$	(474)	$	151,700

Schedule of amortized cost and fair value by contractual maturity

The amortized cost and fair value of the Company’s held‑to‑maturity securities by contractual maturity at April 30, 2019, are as follows:

	Cost		Fair Value
Due within one year	$	150,487	$	150,498
Due after one year through five years		9,386		9,417
Total	$	159,873	$	159,915

Available-for-sale securities

Investments

Schedule of amortized cost, gross unrealized gains, gross unrealized losses, and estimated fair value of available-for-sale investments

	April 30,
	2019		2018
Auction rate securities
Amortized cost	$	-	$	2,250
Gross unrealized losses		-		(108)
Fair value	$	-	$	2,142