Investments (Tables)

6 Months Ended

Oct. 27, 2018

Investments

Schedule of investments

Investments consist of the following (in thousands):

	October 27,		April 30,
	2018		2018
Short-term investments:
Held-to-maturity securities:
Municipal securities	$	14,326	$	35,344
U.S. government securities		36,948		31,620
Corporate bonds		82,262		46,685
Certificates of deposit		5,000		—
Total held-to-maturity and short-term investments	$	138,536	$	113,649
Long-term investments:
Held-to-maturity securities:
Municipal securities	$	993	$	2,046
U.S. government securities		26,746		27,356
Corporate bonds		2,720		9,112
Total held-to-maturity investments		30,459		38,514
Available-for-sale securities:
Auction rate securities		—		2,142
Total available-for-sale investments		—		2,142
Total long-term investments	$	30,459	$	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 gains, gross unrealized losses, and estimated fair value of the held-to-maturity investments as of October 27, 2018 were as follows (in thousands):

	October 27, 2018
			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
Municipal securities	$	15,319	$	—	$	(12)	$	15,307
U.S. government securities		63,694		3		(271)		63,426
Corporate bonds		84,982		2		(76)		84,908
Certificates of deposit		5,000		—		—		5,000
Total held-to-maturity investments	$	168,995	$	5	$	(359)	$	168,641

The amortized cost, gross unrealized gains, gross unrealized losses, and estimated fair value of the held-to-maturity investments as of April 30, 2018 were as follows (in thousands):

	April 30, 2018
			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
Municipal securities	$	37,390	$	9	$	(36)	$	37,363
U.S. government securities		58,976		—		(367)		58,609
Corporate bonds		55,797		2		(71)		55,728
Certificates of deposit		—		—		—		—
Total held-to-maturity investments	$	152,163	$	11	$	(474)	$	151,700

Schedule of amortized cost and fair value by contractual maturity

The amortized cost and fair value of the held-to-maturity securities by contractual maturity at October 27, 2018 were as follows (in thousands):

	Cost		Fair Value
Due within one year	$	138,536	$	138,270
Due after one year through five years		30,459		30,371
Total	$	168,995	$	168,641

Available-for-sale securities | Auction rate securities

Investments

Schedule of amortized cost and fair value by contractual maturity

			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
Auction rate securities	$	2,250	$	—	$	(108)	$	2,142
Total available-for-sale investments	$	2,250	$	—	$	(108)	$	2,142