Business Segment Information - Operating Results by Business Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2017	Apr. 30, 2016
Segment Reporting Information [Line Items]
Net revenue	$ 15,411	$ 11,182
Sales and marketing costs	(3,261)	(3,445)
Stock compensation expense	(2,662)	(2,599)
Consolidated
Segment Reporting Information [Line Items]
Net revenue	15,411	11,182
Direct cost of services	(9,649)	(8,628)
Sales and marketing costs	(3,060)	(3,247)
Other operating expenses	(6,849)	(7,024)
Stock compensation expense	(2,662)	(2,599)
Segment loss	(6,809)	(10,316)
Operating Segments | Personalized Oncology Solutions (POS)
Segment Reporting Information [Line Items]
Net revenue	1,720	1,972
Direct cost of services	(1,431)	(2,075)
Sales and marketing costs	(540)	(833)
Other operating expenses	0	0
Stock compensation expense	0	0
Segment loss	(251)	(936)
Operating Segments | Translational Oncology Solutions (TOS)
Segment Reporting Information [Line Items]
Net revenue	13,691	9,210
Direct cost of services	(8,218)	(6,553)
Sales and marketing costs	(2,520)	(2,414)
Other operating expenses	(4,077)	(3,886)
Stock compensation expense	0	0
Segment loss	(1,124)	(3,643)
Unallocated Corporate Overhead
Segment Reporting Information [Line Items]
Net revenue	0	0
Direct cost of services	0	0
Sales and marketing costs	0	0
Other operating expenses	(2,772)	(3,138)
Stock compensation expense	(2,662)	(2,599)
Segment loss	$ (5,434)	$ (5,737)