Note 3 - Stock-based Compensation - Stock Option Activity (Details) - $ / shares	3 Months Ended		12 Months Ended
	Mar. 28, 2020	Dec. 28, 2019	Sep. 28, 2019
Unvested (in shares)	79,400	59,400
Vested (in shares)	158,100	171,937
Outstanding (in shares)	237,500	231,337
Outstanding, weighted average exercise price (in dollars per share)	$ 7.28	$ 8.36
Outstanding, weighted average contractual life (Year)	4 years 120 days	4 years 164 days	3 years 346 days
Grants (in shares)		20,000
Grants (in shares)		20,000
Grants, weighted average exercise price (in dollars per share)		$ 1.87
Grants, weighted average contractual life (Year)		9 years 343 days
Cancellations/forfeitures (in shares)	(7,000)	(13,837)
Cancellations/forfeitures (in shares)	(7,000)	(13,837)
Cancellations/forfeitures, weighted average exercise price (in dollars per share)	$ 7.02	$ 11.51
Vested (in shares)	(6,300)
Vested (in shares)	6,300
Vested, weighted average exercise price (in dollars per share)	$ 4.22
Unvested (in shares)	73,100	79,400	59,400
Vested (in shares)	157,400	158,100	171,937
Outstanding (in shares)	230,500	237,500	231,337
Outstanding, , weighted average exercise price (in dollars per share)	$ 7.28	$ 7.28	$ 8.36