Condensed Consolidated Statements of Income and Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2018	Jul. 31, 2017
Revenues	$ 11,011	$ 12,023
Cost of revenues	6,737	7,502
Gross margin	4,274	4,521
Selling and administrative expenses	2,540	2,712
Research and development expense	1,649	1,629
Operating income	85	180
Other income (expense):
Investment income	45	1,154
Interest expense	(18)	(21)
Other (expense) income, net	(74)	2
Income before provision for income taxes	38	1,315
Provision for income taxes	7	485
Net income from continuing operations	31	830
Loss from discontinued operations, net of tax	0	(216)
Net income	$ 31	$ 614
Net income per common share:
Basic earnings from continued operations (in Dollars per share)	$ 0.00	$ 0.09
Basic loss from discontinued operations (in Dollars per share)		(0.02)
Basic earnings per share (in Dollars per share)	0.00	0.07
Diluted earnings from continued operations (in Dollars per share)	0.00	0.09
Diluted loss from discontinued operations (in Dollars per share)		(0.02)
Diluted earnings per share (in Dollars per share)	$ 0.00	$ 0.07
Weighted average shares outstanding:
Basic (in Shares)	8,876,416	8,826,026
Diluted (in Shares)	8,990,471	8,967,307
Condensed Consolidated Statements of Comprehensive (Loss) Income
Net income	$ 31	$ 614
Foreign currency translation adjustment	(36)	315
Change in market value of marketable securities before reclassification, net of tax of ($19) in 2017	(8)	34
Reclassification adjustment for realized gains included in net income, net of tax of $355 in 2017	0	(689)
Total unrealized loss on marketable securities, net of tax	(8)	(655)
Total other comprehensive loss	(44)	(340)
Comprehensive (loss) income	$ (13)	$ 274