NOTE J - RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS (Details) - Schedule of New Accounting Pronouncements and Changes in Accounting Principles - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Oct. 31, 2018	Jul. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017	May 01, 2018	Apr. 30, 2018
ASSETS
Costs and estimated earnings in excess of billings, net		$ 7,047			$ 7,047			$ 5,094
Inventories, net		25,648			25,648			26,186
Prepaid expenses and other		1,001			1,001			1,050
Total current assets		51,680			51,680			52,075
Other assets		3,628			3,628			2,850
Total assets		83,662			83,662			83,584
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accrued liabilities		3,179			3,179			3,416
Total current liabilities		4,252			4,252			5,257
Deferred rent and other liabilities		1,479			1,479			1,524
Total liabilities		19,438			19,438			20,322
Accumulated deficit		572			572			(65)
Total stockholders’ equity		64,224	$ 63,970		64,224		$ 63,746	63,262
Total liabilities and stockholders’ equity		83,662			83,662			83,584
Revenues		12,142		$ 9,337	23,153	$ 21,360
Cost of revenues		8,123		7,134	14,860	14,636
Gross profit		4,019		2,203	8,293	6,724
Selling and administrative expenses		2,642		2,335	5,182	5,046
Operating profit (loss)		(230)		(1,866)	(146)	(1,686)
Income (loss) before provision for income taxes		92			130
Net income (loss)		122	$ 31	$ (1,481)	153	$ (867)
Accounting Standards Update 2014-09 [Member]
ASSETS
Costs and estimated earnings in excess of billings, net	[1]	3,487			3,487			1,435
Inventories, net	[2]	(1,994)			(1,994)			(929)
Prepaid expenses and other	[3]	46			46			77
Total current assets		1,539			1,539			583
Other assets	[4]	5			5			10
Total assets		1,544			1,544			593
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accrued liabilities	[5]	61			61			97
Total current liabilities		61			61			97
Deferred rent and other liabilities	[6]	12			12			12
Total liabilities		73			73			109
Accumulated deficit	[7]	1,471			1,471			484
Total stockholders’ equity		1,471			1,471			484
Total liabilities and stockholders’ equity		1,544			1,544			593
Revenues		1,242			2,052
Cost of revenues		838			1,065
Gross profit		403			989
Selling and administrative expenses	[1]	(9)			0
Operating profit (loss)		413			988
Income (loss) before provision for income taxes		413			988
Net income (loss)		413			988
Balances Without Adoption [Member]
ASSETS
Costs and estimated earnings in excess of billings, net		3,560			3,560			6,529
Inventories, net		27,642			27,642			25,257
Prepaid expenses and other		955			955			1,127
Total current assets		50,141			50,141			52,658
Other assets		3,623			3,623			2,860
Total assets		82,118			82,118			84,177
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accrued liabilities		3,118			3,118			3,513
Total current liabilities		4,191			4,191			5,354
Deferred rent and other liabilities		1,467			1,467			1,536
Total liabilities		19,365			19,365			20,431
Accumulated deficit		(899)			(899)			419
Total stockholders’ equity		62,753			62,753			63,746
Total liabilities and stockholders’ equity		82,118			82,118			$ 84,177
Revenues		10,900			21,101
Cost of revenues		7,285			13,795
Gross profit		3,616			7,304
Selling and administrative expenses		2,651			5,182
Operating profit (loss)		(643)			(1,134)
Income (loss) before provision for income taxes		(321)			(858)
Net income (loss)		$ (291)			$ (835)

[1] Adjustment to unbilled accounts receivable for additional revenue recognized for which amounts have not been invoiced due to adoption of Topic 606

[2] Adjustment for additional allocated inventory costs related to additional revenue recognized due to adoption of Topic 606

[3] Adjustment for short-term capitalization of sales commissions, net of amortized amounts, due to adoption of ASC 340-40

[4] Adjustment for long-term capitalization of sales commissions, net of amortized amounts, due to adoption of ASC 340-40

[5] Adjustment to record short-term liability of sales commissions, net of amounts paid, due to adoption of ASC 340-40

[6] Adjustment to record long-term liability of sales commissions, net of amounts paid, due to adoption of ASC 340-40

[7] The cumulative effect of initially adopting Topic 606 and ASC 340-40 using the modified-retrospective method as an adjustment to the beginning balance of (Accumulated deficit) Retained earnings.