Condensed Consolidated Statements of Income and Comprehensive (Loss) Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Revenues	$ 12,914	$ 16,003	$ 25,622	$ 32,684
Cost of revenues	8,801	10,779	17,395	21,686
Gross margin	4,113	5,224	8,227	10,998
Selling and administrative expenses	3,272	3,230	6,598	6,916
Research and development expenses	2,188	1,946	3,772	3,093
Operating (loss) profit	(1,347)	48	(2,143)	989
Other income (expense):
Investment income	187	94	278	365
Interest expense	(26)	(32)	(67)	(56)
Other (expense) income, net	(2)	1	(2)	404
(Loss) income before provision for income taxes	(1,188)	111	(1,934)	1,702
Provision for income taxes	(164)	180	(204)	880
Net (loss) income	$ (1,024)	$ (69)	$ (1,730)	$ 822
Net (loss) income per common share
Basic (in Dollars per share)	$ (0.12)	$ (0.01)	$ (0.20)	$ 0.09
Diluted (in Dollars per share)	$ (0.12)	$ (0.01)	$ (0.20)	$ 0.09
Weighted average shares outstanding
Basic (in Shares)	8,780,633	8,725,128	8,771,494	8,715,656
Diluted (in Shares)	8,780,633	8,725,128	8,771,494	8,959,150
Condensed Consolidated Statements of Comprehensive (Loss) Income
Net (loss) income	$ (1,024)	$ (69)	$ (1,730)	$ 822
Other comprehensive income:
Foreign currency translation adjustment	984	91	369	792
Unrealized gain (loss) on marketable securities:
Change in market value of marketable securities before reclassification, net of tax of ($61) and $148	(194)	(104)	118	(289)
Reclassification adjustment for realized gains included in net income, net of tax of $47 in 2015	0	0	0	(90)
Total unrealized gain (loss) on marketable securities, net of tax	(194)	(104)	118	(379)
Total other comprehensive income	790	(13)	487	413
Comprehensive (loss) income	$ (234)	$ (82)	$ (1,243)	$ 1,235