Description of Company and Basis of Presentation (Details - Consolidated balance sheet) - USD ($) $ in Thousands	Jul. 31, 2023	Apr. 30, 2023	Jul. 31, 2022	Apr. 30, 2022
Current assets:
Cash and cash equivalents	$ 24,898	$ 38,542	$ 115,137	$ 126,166
Accounts receivable, net	16,209	18,298
Contract assets	14,454	9,609
Inventory	40,866	43,908
Prepaid expenses and other current assets	1,892	2,094
Total current assets	98,319	112,451
Property and equipment, net	182,835	177,770
Operating lease right-of-use assets	42,374	42,772
Deferred tax assets	114,371	113,751
Other assets	4,757	4,473
Restricted cash	350	350	350	350
Total assets	443,006	451,567
Current liabilities:
Accounts payable	22,813	24,593
Accrued compensation and benefits	4,667	8,780
Contract liabilities	33,019	37,352
Convertible senior notes, net	140,888	140,623
Current portion of operating lease liabilities	1,262	1,358
Other current liabilities	3,295	2,440
Total current liabilities	205,944	215,146
Convertible senior notes, net	0
Operating lease liabilities, less current portion	45,370	45,690
Finance lease liabilities, less current portion	1,424	1,562
Total liabilities	252,738	262,398
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value; 5,000 shares authorized; no shares issued and outstanding at respective dates	0	0
Common stock, $0.001 par value; 150,000 shares authorized; 63,111 and 62,692 shares issued and outstanding at respective dates	63	63
Additional paid-in capital	623,445	620,224
Accumulated deficit	(433,240)	(431,118)
Total stockholders’ equity	190,268	189,169	$ 178,796	$ 174,526
Total liabilities and stockholders’ equity	443,006	451,567
Previously Reported [Member]
Current assets:
Cash and cash equivalents	24,898
Accounts receivable, net	16,209
Contract assets	14,454
Inventory	40,866
Prepaid expenses and other current assets	1,892
Total current assets	98,319
Property and equipment, net	182,299
Operating lease right-of-use assets	42,374
Deferred tax assets	114,238
Other assets	4,757
Restricted cash	350
Total assets	442,337
Current liabilities:
Accounts payable	22,813
Accrued compensation and benefits	4,667
Contract liabilities	33,019
Convertible senior notes, net	0
Current portion of operating lease liabilities	1,262
Other current liabilities	2,296
Total current liabilities	64,057
Convertible senior notes, net	140,888
Operating lease liabilities, less current portion	45,370
Finance lease liabilities, less current portion	1,424
Total liabilities	251,739
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value; 5,000 shares authorized; no shares issued and outstanding at respective dates	0
Common stock, $0.001 par value; 150,000 shares authorized; 63,111 and 62,692 shares issued and outstanding at respective dates	63
Additional paid-in capital	623,445
Accumulated deficit	(432,910)
Total stockholders’ equity	190,598	189,470
Total liabilities and stockholders’ equity	442,337
Revision of Prior Period, Adjustment [Member]
Current assets:
Cash and cash equivalents	0
Accounts receivable, net	0
Contract assets	0
Inventory	0
Prepaid expenses and other current assets	0
Total current assets	0
Property and equipment, net	536
Operating lease right-of-use assets	0
Deferred tax assets	133
Other assets	0
Restricted cash	0
Total assets	669
Current liabilities:
Accounts payable	0
Accrued compensation and benefits	0
Contract liabilities	0
Convertible senior notes, net	140,888
Current portion of operating lease liabilities	0
Other current liabilities	999
Total current liabilities	141,887
Convertible senior notes, net	(140,888)
Operating lease liabilities, less current portion	0
Finance lease liabilities, less current portion	0
Total liabilities	999
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value; 5,000 shares authorized; no shares issued and outstanding at respective dates	0
Common stock, $0.001 par value; 150,000 shares authorized; 63,111 and 62,692 shares issued and outstanding at respective dates	0
Additional paid-in capital	0
Accumulated deficit	(330)
Total stockholders’ equity	(330)	$ (301)
Total liabilities and stockholders’ equity	$ 669