1. Summary of Accounting Policies (Details) - Schedule of New Accounting Pronouncements and Changes in Accounting Principles - USD ($) $ in Thousands		12 Months Ended
		Apr. 30, 2019	Apr. 30, 2018	May 01, 2018	Apr. 30, 2017
ASSETS
Costs and estimated earnings in excess of billings, net		$ 6,670	$ 5,094	$ 6,529
Inventories, net		23,356	26,186	25,257
Prepaid expenses and other		2,583	1,050	1,127
Total current assets		52,699	52,075	52,658
Other assets		5,923	2,850	2,860
Total assets		86,771	83,584	84,177
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accrued liabilities		3,571	3,416	3,513
Total current liabilities		5,837	5,257	5,354
Deferred rent and other liabilities		1,376	1,524	1,536
Total liabilities		23,682	20,322	20,431
(Accumulated deficit) Retained Earnings		(2,111)	(65)	419
Total stockholders’ equity		63,089	63,262	63,746	$ 89,332
Total liabilities and stockholders’ equity		86,771	83,584	84,177
Revenues		49,509	39,407
Cost of revenues		33,720	34,244
Gross profit		15,789	5,163
Selling and administrative expenses		12,100	10,608
Operating loss		(2,817)	(12,395)
Loss before provision for income taxes		(2,473)
Net loss		(2,529)	$ (23,777)
Adjustments for New Accounting Pronouncement [Member]
ASSETS
Costs and estimated earnings in excess of billings, net	[1]			1,435
Inventories, net	[2]			(929)
Prepaid expenses and other	[3]			77
Total current assets				583
Other assets	[4]			10
Total assets				593
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accrued liabilities	[5]			97
Total current liabilities				97
Deferred rent and other liabilities	[6]			12
Total liabilities				109
(Accumulated deficit) Retained Earnings	[7]			484
Total stockholders’ equity				484
Total liabilities and stockholders’ equity				$ 593
Accounting Standards Update 2014-09 [Member]
ASSETS
Costs and estimated earnings in excess of billings, net	[8]	4,087
Inventories, net	[9]	(3,437)
Prepaid expenses and other	[10]	56
Total current assets		706
Other assets	[11]	15
Total assets		721
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accrued liabilities	[12]	75
Total current liabilities		75
Deferred rent and other liabilities	[13]	12
Total liabilities		87
(Accumulated deficit) Retained Earnings	[14]	632
Total stockholders’ equity		632
Total liabilities and stockholders’ equity		721
Revenues		2,662
Cost of revenues		2,508
Gross profit		154
Selling and administrative expenses	[15]	5
Operating loss		149
Loss before provision for income taxes		149
Net loss		149
Balances Without Adoption [Member]
ASSETS
Costs and estimated earnings in excess of billings, net		2,583
Inventories, net		26,793
Prepaid expenses and other		2,527
Total current assets		51,993
Other assets		5,908
Total assets		86,050
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accrued liabilities		3,496
Total current liabilities		5,762
Deferred rent and other liabilities		1,364
Total liabilities		23,595
(Accumulated deficit) Retained Earnings		(2,743)
Total stockholders’ equity		62,457
Total liabilities and stockholders’ equity		86,050
Revenues		46,847
Cost of revenues		31,212
Gross profit		15,635
Selling and administrative expenses		12,095
Operating loss		(2,996)
Loss before provision for income taxes		(2,622)
Net loss		$ (2,678)

[1] Adjustment to unbilled accounts receivable for additional revenue recognized for which amounts have not been invoiced due to adoption of ASU 2014-09.

[2] Adjustment for additional allocated inventory costs related to additional revenue recognized due to adoption of ASU 2014-09.

[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 ASU 2014-09 and ASC 340-40 using the modified-retrospective method as an adjustment to the beginning balance of (Accumulated deficit) Retained Earnings.

[8] Cumulative adjustment to unbilled accounts receivable for additional revenue recognized for which amounts have not been invoiced due to adoption of ASU 2014-09.

[9] Cumulative adjustment for additional allocated inventory costs related to additional revenue recognized due to adoption of ASU 2014-09.

[10] Cumulative adjustment for short-term capitalization of sales commissions, net of amortized amounts, due to adoption of ASC 340-40.

[11] Cumulative adjustment for long-term capitalization of sales commissions, net of amortized amounts, due to adoption of ASC 340-40.

[12] Cumulative adjustment to record short-term liability of sales commissions, net of amounts paid, due to adoption of ASC 340-40.

[13] Cumulative adjustment to record long-term liability of sales commissions, net of amounts paid, due to adoption of ASC 340-40.

[14] The cumulative effect of initially adopting for ASU 2014-09 and ASC 340-40 using the modified-retrospective method as an adjustment to the balance of Retained earnings (Accumulated deficit).

[15] Additional expense related the amortization of sales commissions due to the adoptions of ASC 340-40.