Note 7 - Stock-based Compensation - Stock Option Compensation (Details) - USD ($)	3 Months Ended
	Jun. 30, 2019	Jul. 01, 2018
Allocated share-based compensation	$ 65,000	$ 110,000
Share-based Payment Arrangement, Option [Member]
Allocated share-based compensation	9,000	27,000
Share-based Payment Arrangement, Option [Member] | Cost of Sales [Member]
Allocated share-based compensation	7,000	13,000
Share-based Payment Arrangement, Option [Member] | Marketing and Administrative Expenses [Member]
Allocated share-based compensation	2,000	14,000
Share-based Payment Arrangement, Option [Member] | Fiscal Year 2017 [Member]
Allocated share-based compensation		11,000
Share-based Payment Arrangement, Option [Member] | Fiscal Year 2017 [Member] | Cost of Sales [Member]
Allocated share-based compensation		6,000
Share-based Payment Arrangement, Option [Member] | Fiscal Year 2017 [Member] | Marketing and Administrative Expenses [Member]
Allocated share-based compensation		5,000
Share-based Payment Arrangement, Option [Member] | Fiscal Year 2018 [Member]
Allocated share-based compensation	5,000	15,000
Share-based Payment Arrangement, Option [Member] | Fiscal Year 2018 [Member] | Cost of Sales [Member]
Allocated share-based compensation	4,000	7,000
Share-based Payment Arrangement, Option [Member] | Fiscal Year 2018 [Member] | Marketing and Administrative Expenses [Member]
Allocated share-based compensation	1,000	8,000
Share-based Payment Arrangement, Option [Member] | Fiscal Year 2019 [Member]
Allocated share-based compensation	3,000	1,000
Share-based Payment Arrangement, Option [Member] | Fiscal Year 2019 [Member] | Cost of Sales [Member]
Allocated share-based compensation	3,000
Share-based Payment Arrangement, Option [Member] | Fiscal Year 2019 [Member] | Marketing and Administrative Expenses [Member]
Allocated share-based compensation		1,000
Share-based Payment Arrangement, Option [Member] | Fiscal Year 2020 [Member]
Allocated share-based compensation	1,000
Share-based Payment Arrangement, Option [Member] | Fiscal Year 2020 [Member] | Cost of Sales [Member]
Allocated share-based compensation
Share-based Payment Arrangement, Option [Member] | Fiscal Year 2020 [Member] | Marketing and Administrative Expenses [Member]
Allocated share-based compensation	$ 1,000