Cash and Cash Equivalents (Details) - USD ($)	Feb. 29, 2020	May 31, 2019	Feb. 28, 2019	May 31, 2018
Summary of cash and cash equivalents
Cash in banks	$ 3,171,564	$ 3,072,218
Money market funds	301,718	622,771
Total	$ 3,473,282	$ 3,694,989	$ 4,112,155	$ 5,323,437

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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