Industry Segments - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2021	Jan. 31, 2020
Segment Reporting Information [Line Items]
Revenues	$ 27,683	$ 30,600	$ 82,842	$ 86,193
Operating income (loss)	935	2,819	2,451	4,459
Capital expenditures	298	101	461	339
Capitalized software	233	807	604	2,697
Depreciation and amortization	1,247	1,882	4,441	6,310
Earnings (loss) before income taxes	2,367	3,797	5,173	6,674
Supply Chain Management
Segment Reporting Information [Line Items]
Revenues	22,646	25,578	66,679	71,411
Operating income (loss)	4,713	6,693	12,800	14,904
Capital expenditures	152	43	236	117
Capitalized software	233	807	604	2,697
Depreciation and amortization	1,149	1,785	4,150	6,026
Earnings (loss) before income taxes	4,803	6,743	13,023	15,259
IT Consulting
Segment Reporting Information [Line Items]
Revenues	4,543	4,475	14,602	13,011
Operating income (loss)	83	43	292	210
Capital expenditures	0	0	0	0
Capitalized software	0	0	0	0
Depreciation and amortization	0	2	2	4
Earnings (loss) before income taxes	83	43	290	209
Other
Segment Reporting Information [Line Items]
Revenues	494	547	1,561	1,771
Operating income (loss)	(3,861)	(3,917)	(10,641)	(10,655)
Capital expenditures	146	58	225	222
Capitalized software	0	0	0	0
Depreciation and amortization	98	95	289	280
Earnings (loss) before income taxes	$ (2,519)	$ (2,989)	$ (8,140)	$ (8,794)