2. Investments

Investments consist of the following (in thousands):


	July 29,		April 30,
	2017		2017
Short-term investments:
Held-to-maturity securities:
Municipal securities	$	37,164	$	47,437
U.S. government securities		16,104		14,515
Corporate bonds		52,063		55,519
Certificates of deposit		2,500		2,500
Total held-to-maturity and short-term investments	$	107,831	$	119,971
Long-term investments:
Held-to-maturity securities:
Municipal securities	$	4,751	$	8,942
U.S. government securities		29,040		22,540
Corporate bonds		—		8,117
Total held-to-maturity investments		33,791		39,599
Available-for-sale securities:
Auction rate securities		2,053		2,497
Total available-for-sale investments		2,053		2,497
Total long-term investments	$	35,844	$	42,096

Held-To-Maturity Securities

As of July 29, 2017 and April 30, 2017, the balance of held-to-maturity securities consisted of state and local government municipal securities, U.S. treasury securities, U.S. government-guaranteed agency securities, U.S. government-sponsored agency debt securities, certificates of deposit and highly rated corporate bonds. Interest earned from these investments is recorded in interest income.

The amortized cost, gross unrealized gains, gross unrealized losses, and estimated fair value of the held-to-maturity investments as of July 29, 2017 were as follows (in thousands):


	July 29, 2017
			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
Municipal securities	$	41,915	$	32	$	(6)	$	41,941
U.S. government securities		45,144		2		(48)		45,098
Corporate bonds		52,063		4		(66)		52,001
Certificates of deposit		2,500		1		—		2,501
Total held-to-maturity investments	$	141,622	$	39	$	(120)	$	141,541

The amortized cost, gross unrealized gains, gross unrealized losses, and estimated fair value of the held-to-maturity investments as of April 30, 2017 were as follows (in thousands):


			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
Municipal securities	$	56,379	$	30	$	(21)	$	56,388
U.S. government securities		37,055		2		(41)		37,016
Corporate bonds		63,636		9		(85)		63,560
Certificates of deposit		2,500		1		—		2,501
Total held-to-maturity investments	$	159,570	$	42	$	(147)	$	159,465

The amortized cost and fair value of the held-to-maturity securities by contractual maturity at July 29, 2017 were as follows (in thousands):


	Cost		Fair Value
Due within one year	$	107,831	$	107,768
Due after one year through five years		33,791		33,773
Total	$	141,622	$	141,541

Available-For-Sale Securities

Auction Rate Securities

As of July 29, 2017 and April 30, 2017, the entire balance of available-for-sale auction rate securities, consisted of two investment grade auction rate municipal bonds, with maturities of approximately 2 and 17 years, respectively. These investments have characteristics similar to short-term investments, because at pre-determined intervals, generally ranging from 30 to 35 days, there is a new auction process at which the interest rates for these securities are reset to current interest rates. At the end of such period, the Company chooses to roll-over its holdings or redeem the investments for cash. A market maker facilitates the redemption of the securities and the underlying issuers are not required to redeem the investment within 365 days. Interest earned from these investments is recorded in interest income.

During the fourth quarter of the fiscal year ended April 30, 2008, the Company began experiencing failed auctions on some of its auction rate securities. A failed auction occurs when a buyer for the securities cannot be obtained and the market maker does not buy the security for its own account. The Company continues to earn interest on the investments that failed to settle at auction, at the maximum contractual rate until the next auction occurs. In the event the Company needs to access funds invested in these auction rate securities, the Company may not be able to liquidate these securities at the fair value recorded on July 29, 2017, until a future auction of these securities is successful or a buyer is found outside of the auction process.

As a result of the failed auctions, the fair values of these securities are estimated utilizing a discounted cash flow analysis as of July 29, 2017. The analysis considers, among other items, the collateralization underlying the security investments, the creditworthiness of the counterparty, the timing of expected future cash flows, and the estimated date upon which the security is expected to have a successful auction. Based on the Company’s ability to access its cash and cash equivalents, expected operating cash flows, and other sources of cash, the Company does not anticipate that the current lack of liquidity of these investments will affect its ability to operate its business in the ordinary course. The Company believes the current lack of liquidity of these investments is temporary and expects that the securities will be redeemed or refinanced at some point in the future. The Company will continue to monitor the value of its auction rate securities at each reporting period for a possible impairment if a further decline in fair value occurs. The auction rate securities have been in an unrealized loss position for more than 12 months. The Company has the ability and the intent to hold these investments until a recovery of fair value, which may be at maturity. As of July 29, 2017, the Company did not consider these investments to be other-than-temporarily impaired.

The amortized cost, gross unrealized gains, gross unrealized losses, and estimated fair value of the auction rate securities as of July 29, 2017, were as follows (in thousands):


			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
Auction rate securities	$	2,250	$	—	$	(197)	$	2,053
Total available-for-sale investments	$	2,250	$	—	$	(197)	$	2,053

The amortized cost, gross unrealized gains, gross unrealized losses, and estimated fair value of the auction rate securities as of April 30, 2017, were as follows (in thousands):


			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
Auction rate securities	$	2,700	$	—	$	(203)	$	2,497
Total available-for-sale investments	$	2,700	$	—	$	(203)	$	2,497

The amortized cost and fair value of the auction rate securities by contractual maturity at July 29, 2017, were as follows (in thousands):


	Cost		Fair Value
Due after one through five years	$	250	$	251
Due after 10 years		2,000		1,802
Total	$	2,250	$	2,053