Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Feb. 28, 2022	May 31, 2021
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	166,666,666	166,666,666
Common stock, shares issued (in shares)	53,396,920	53,396,920
Common stock, shares outstanding (in shares)	1,511,061	1,511,061
Treasury stock, (in shares)	36,300	36,300
Series C Convertible Redeemable Preferred Stock
Temporary equity, par value (in dollars per share)	$ 0.001	$ 0.001
Temporary equity authorized (in shares)	676,086	660,000
Temporary equity issued (in shares)	676,086	660,000
Temporary equity outstanding (in shares)	676,086	660,000
Series D Convertible Redeemable Preferred Stock
Temporary equity, par value (in dollars per share)	$ 0.001	$ 0.001
Temporary equity authorized (in shares)	1,413,624	0
Temporary equity issued (in shares)	1,413,624	0
Temporary equity outstanding (in shares)	1,413,624	0
Series A Preferred Stock
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	70,000	70,000
Preferred stock, shares outstanding (in shares)	0	27,195
Preferred stock, shares issued (in shares)	0	27,195
Series B Preferred Stock
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	50,000	50,000
Preferred stock, shares outstanding (in shares)	0	17,087
Preferred stock, shares issued (in shares)	0	17,087

Face amount or stated value per share of common stock.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

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Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.

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Per share amount of par value or stated value of stock classified as temporary equity. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable.

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Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends.

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