9. RESTRUCTURING (Details Narrative) - USD ($)	3 Months Ended		9 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2018	Jan. 31, 2017
Aggregate restructuring costs	$ 0	$ 0	$ 1,258,000	$ 0
Restructuring [Member]
Workforce reduction			We reduced our overall workforce by 57 employees
Aggregate restructuring costs			$ 1,588,000
Restructuring [Member] | Research and Development Segment [Member]
Aggregate restructuring costs			330,000
Restructuring [Member] | Contract Manufacturing Services Segment [Member]
Aggregate restructuring costs			$ 1,258,000