Segment Information - Summary of Segment Activity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Segment Reporting Information [Line Items]
Net revenue	$ 5,203	$ 4,457	$ 10,237	$ 8,126
Sales and marketing costs	(551)	(717)	(1,235)	(1,643)
Stock- based compensation expense	(148)	(535)	(711)	(1,664)
Consolidated
Segment Reporting Information [Line Items]
Net revenue	5,203	4,457	10,237	8,126
Direct cost of services	(2,651)	(2,200)	(5,265)	(4,677)
Sales and marketing costs	(544)	(699)	(1,194)	(1,456)
Other operating expenses	(1,930)	(1,516)	(3,756)	(3,346)
Stock- based compensation expense	(148)	(535)	(711)	(1,664)
Segment profit (loss)	(70)	(493)	(689)	(3,017)
Operating Segments | Personalized Oncology Solutions (POS)
Segment Reporting Information [Line Items]
Net revenue	378	497	818	1,007
Direct cost of services	(259)	(374)	(645)	(845)
Sales and marketing costs	(85)	(128)	(171)	(269)
Other operating expenses	0	0	0	0
Stock- based compensation expense	0	0	0	0
Segment profit (loss)	34	(5)	2	(107)
Operating Segments | Translational Oncology Solutions (TOS)
Segment Reporting Information [Line Items]
Net revenue	4,825	3,960	9,419	7,119
Direct cost of services	(2,392)	(1,826)	(4,620)	(3,832)
Sales and marketing costs	(459)	(571)	(1,023)	(1,187)
Other operating expenses	(1,073)	(964)	(2,111)	(2,090)
Stock- based compensation expense	0	0	0	0
Segment profit (loss)	901	599	1,665	10
Unallocated Corporate Overhead
Segment Reporting Information [Line Items]
Net revenue	0	0	0	0
Direct cost of services	0	0	0	0
Sales and marketing costs	0	0	0	0
Other operating expenses	(857)	(552)	(1,645)	(1,256)
Stock- based compensation expense	(148)	(535)	(711)	(1,664)
Segment profit (loss)	$ (1,005)	$ (1,087)	$ (2,356)	$ (2,920)