Marketable Securities (Tables)
 12 Months Ended
Apr. 27, 2019
Marketable Securities [Abstract]  
Available-for-sale Securities
As of April 27, 2019 and April 28, 2018, our available-for-sale securities consisted of the following:
 
Amortized Cost
 
Unrealized Losses
 
Fair Value
Balance as of April 27, 2019:
 
 
 
 
 
Certificates of deposit
$
3,464

 
$
—

 
$
3,464

U.S. Government securities
10,779

 
(5
)
 
10,774

U.S. Government sponsored entities
10,510

 
(28
)
 
10,482

Municipal bonds
1,626

 
(2
)
 
1,624

 
$
26,379

 
$
(35
)
 
$
26,344

Balance as of April 28, 2018:
 

 
 

 
 

Certificates of deposit
$
8,669

 
$
—

 
$
8,669

U.S. Government securities
999

 
(7
)
 
992

U.S. Government sponsored entities
20,072

 
(123
)
 
19,949

Municipal bonds
4,936

 
(24
)
 
4,912

 
$
34,676

 
$
(154
)
 
$
34,522
Investments Classified by Contractual Maturity Date
The contractual maturities of available-for-sale debt securities as of April 27, 2019 were as follows:
 
Less than 12 months
 
1-5 Years
 
Total
Certificates of deposit
$
2,234

 
$
1,230

 
$
3,464

U.S. Government securities
10,774

 
—

 
10,774

U.S. Government sponsored entities
7,245

 
3,237

 
10,482

Municipal bonds
1,624

 
—

 
1,624

 
$
21,877

 
$
4,467

 
$
26,344