Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2024	Jan. 31, 2023	Jan. 31, 2024	Jan. 31, 2023
Income Statement [Abstract]
Revenues	$ 13,714	$ 10,620	$ 39,698	$ 27,773
Cost of revenues	10,610	7,155	27,396	23,963
Gross margin	3,104	3,465	12,302	3,810
Selling and administrative expenses	2,619	2,357	7,473	6,383
Research and development expenses	958	783	2,304	2,492
Operating (loss) income	(473)	325	2,525	(5,065)
Other income (expense):
Investment income (expense), net	636	(625)	549	(600)
Interest expense	(27)	(18)	(86)	(81)
Other income, net	0	5	0	5
Income (loss) before provision for income taxes	136	(313)	2,988	(5,741)
Provision for income taxes	6	3	19	6
Net income (loss)	$ 130	$ (316)	$ 2,969	$ (5,747)
Net income (loss) per common share:
Basic and diluted income (loss) per share (in Dollars per share)	$ 0.01	$ (0.03)	$ 0.32	$ (0.62)
Weighted average shares outstanding:
Basic and diluted (in Shares)	9,440,000	9,349,000	9,408,000	9,328,000
Net income (loss)	$ 130	$ (316)	$ 2,969	$ (5,747)
Unrealized gain (loss) on marketable securities:
Change in market value of marketable securities before reclassification, net of tax	0	388	0	(179)
Reclassification adjustment for realized gains included in net income (loss), net of tax	0	603	0	619
Total unrealized gain on marketable securities, net of tax	0	991	0	440
Comprehensive income (loss)	$ 130	$ 675	$ 2,969	$ (5,307)