Note 13 - Fair Value Measurements - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Apr. 30, 2019	Apr. 30, 2018
Promissory notes		$ 2,387
Long-term debt	3,975	3,347
	3,975	5,734
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Promissory notes
Long-term debt
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Promissory notes
Long-term debt
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Promissory notes		2,387
Long-term debt	3,975	3,347
	$ 3,975	$ 5,734