Note 7 - Stock-based Compensation - Stock Option Activity (Details) - $ / shares	3 Months Ended
	Jun. 30, 2019	Jul. 01, 2018
Outstanding, Weighted-average exercise price, beginning balance (in dollars per share)	$ 7.45	$ 7.93
Outstanding, Shares, beginning balance (in shares)	457,500	395,000
Granted, Weighted-average exercise price (in dollars per share)	$ 4.76	$ 5.90
Number of options issued (in shares)	125,000	110,000
Forfeited, Weighted-average exercise price (in dollars per share)	$ 7.07
Forfeited, Shares (in shares)	(55,000)
Outstanding, Weighted-average exercise price, ending balance (in dollars per share)	$ 6.85	$ 7.48
Outstanding, Shares, ending balance (in shares)	527,500	505,000
Exercisable, Weighted-average exercise price (in dollars per share)	$ 7.72	$ 8.15
Exercisable, Shares (in shares)	352,500	315,000