Segment Information - Summary of Segment Activity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2018	Jan. 31, 2017
Segment Reporting Information [Line Items]
Net revenue	$ 5,082	$ 3,565	$ 15,319	$ 11,691
Sales and marketing costs	(627)	(726)	(1,862)	(2,369)
Stock- based compensation expense	(152)	(237)	(863)	(1,901)
Consolidated
Segment Reporting Information [Line Items]
Net revenue	5,082	3,565	15,319	11,691
Direct cost of services	(2,471)	(2,404)	(7,706)	(7,081)
Sales and marketing costs	(620)	(719)	(1,815)	(2,175)
Other operating expenses	(1,906)	(1,606)	(5,690)	(4,954)
Stock- based compensation expense	(152)	(237)	(863)	(1,901)
Segment profit (loss)	(67)	(1,401)	(755)	(4,420)
Operating Segments | Personalized Oncology Solutions (POS)
Segment Reporting Information [Line Items]
Net revenue	259	347	1,077	1,354
Direct cost of services	(220)	(320)	(870)	(1,165)
Sales and marketing costs	(94)	(128)	(265)	(397)
Other operating expenses	0	0	0	0
Stock- based compensation expense	0	0	0	0
Segment profit (loss)	(55)	(101)	(58)	(208)
Operating Segments | Translational Oncology Solutions (TOS)
Segment Reporting Information [Line Items]
Net revenue	4,823	3,218	14,242	10,337
Direct cost of services	(2,251)	(2,084)	(6,836)	(5,916)
Sales and marketing costs	(526)	(591)	(1,550)	(1,778)
Other operating expenses	(1,013)	(953)	(3,152)	(3,043)
Stock- based compensation expense	0	0	0	0
Segment profit (loss)	1,033	(410)	2,704	(400)
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	(893)	(653)	(2,538)	(1,911)
Stock- based compensation expense	(152)	(237)	(863)	(1,901)
Segment profit (loss)	$ (1,045)	$ (890)	$ (3,401)	$ (3,812)