CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2020	Jan. 31, 2019
Income Statement [Abstract]
Revenues	$ 13,585	$ 13,781	$ 47,152	$ 36,548
Cost of revenues	12,800	11,731	41,921	32,972
Gross profit	785	2,050	5,231	3,576
Operating expenses:
Selling, general and administrative	2,996	3,242	10,989	9,273
Loss on lease termination	0	0	355	0
Total operating expenses	2,996	3,242	11,344	9,273
Operating loss	(2,211)	(1,192)	(6,113)	(5,697)
Interest and other income, net	107	9	415	190
Loss from continuing operations before income taxes	(2,104)	(1,183)	(5,698)	(5,507)
Income tax benefit	0	44	0	217
Loss from continuing operations, net of tax	(2,104)	(1,139)	(5,698)	(5,290)
Income from discontinued operations, net of tax	0	0	0	739
Net Loss	(2,104)	(1,139)	(5,698)	(4,551)
Comprehensive loss	(2,104)	(1,139)	(5,698)	(4,551)
Series E preferred stock accumulated dividends	(1,442)	(1,442)	(3,604)	(3,604)
Net loss attributable to common stockholders	$ (3,546)	$ (2,581)	$ (9,302)	$ (8,155)
Basic and diluted net (loss) income per common share attributable to common stockholders: Continuing Operations	$ (0.06)	$ (0.05)	$ (0.17)	$ (0.16)
Basic and diluted net (loss) income per common share attributable to common stockholders: Discontinued Operations	0	0	0	0.01
Net loss per common share attributable to common stockholders	$ (0.06)	$ (0.05)	$ (0.17)	$ (0.15)
Weighted average basic and diluted shares outstanding	56,404	56,069	56,275	55,949