Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Apr. 30, 2020	Apr. 30, 2019
Income Statement [Abstract]
Revenues	$ 41,507	$ 49,509
Cost of revenues	35,759	33,720
Gross profit	5,748	15,789
Selling and administrative expenses	11,593	12,100
Research and development expenses	5,077	6,506
Loss from operations	(10,922)	(2,817)
Investment income	329	293
Interest expense	(107)	(83)
Other (expense)/income, net	(1,068)	134
Loss before (benefit) provision for income taxes	(11,768)	(2,473)
(Benefit) provision for income taxes	(1,742)	56
Net loss	$ (10,026)	$ (2,529)
Basic and diluted loss per share (in Dollars per share)	$ (1.10)	$ (0.28)
Basic and diluted (in Shares)	9,074	8,916
Consolidated Statements of Comprehensive Loss
Net loss	$ (10,026)	$ (2,529)
Other comprehensive income:
Foreign currency translation adjustment	0	790
Change in market value of marketable securities before reclassification, net of tax of ($1) in fiscal 2019	443	173
Reclassification adjustment for realized gains included in net income, net of tax of $1 in fiscal 2019	1	(2)
Total unrealized gain on marketable securities, net of tax	444	171
Total other comprehensive income	444	961
Comprehensive loss	$ (9,582)	$ (1,568)