Condensed Consolidated Balance Sheets - USD ($)	Aug. 31, 2020	May 31, 2020
Current assets:
Cash and cash equivalents	$ 15,419,001	$ 15,159,827
Short-term investments	1,077,962	1,071,950
Accounts receivable, net	4,708,831	5,819,471
Inventory	9,550,392	10,107,437
Costs and estimated earnings in excess of billings	1,676,993	1,754,573
Other current assets	513,702	510,360
Total current assets	32,946,881	34,423,618
Maintenance and other inventory, net	1,090,754	879,050
Property and equipment, net	9,362,463	9,407,490
Other assets	196,842	195,621
Deferred income taxes	170,115	170,115
Total assets	43,767,055	45,075,894
Current liabilities:
Short-term borrowings	1,461,500	1,461,500
Accounts payable	1,127,246	1,370,175
Accrued commissions	445,638	305,885
Other current liabilities	856,029	1,663,914
Billings in excess of costs and estimated earnings	109,622	736,866
Total current liabilities	4,000,035	5,538,340
Stockholders' Equity:
Common stock and additional paid-in capital	9,939,006	9,860,006
Retained earnings	32,714,591	32,538,580
Stockholders’ equity before treasury stock	42,653,597	42,398,586
Treasury stock - at cost	(2,886,577)	(2,861,032)
Total stockholders’ equity	39,767,020	39,537,554
Total liabilities and stockholders’ equity	$ 43,767,055	$ 45,075,894