Consolidated Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	480,000,000.0	480,000,000.0
Common stock, shares issued (in shares)	120,800,000	117,800,000
Common stock, shares outstanding (in shares)	120,800,000	117,800,000
Treasury stock, shares (in shares)	346,126,000,000	249,742,000,000
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	500,000	500,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Series A Convertible Preferred Stock [Member]
Temporary equity, liquidation preference (in dollars per share)	$ 1,000	$ 1,000
Temporary equity, shares issued (in shares)	73,713,000	65,507,000
Temporary equity, shares outstanding (in shares)	73,713,000	65,507,000
Series B Convertible Preferred Stock [Member]
Temporary equity, liquidation preference (in dollars per share)	$ 1,000	$ 1,000
Temporary equity, shares issued (in shares)	70,433,000	62,612,000
Temporary equity, shares outstanding (in shares)	70,433,000	62,612,000
Series C Convertible Preferred Stock [Member]
Temporary equity, liquidation preference (in dollars per share)	$ 1,000	$ 1,000
Temporary equity, shares issued (in shares)	42,490,000	0
Temporary equity, shares outstanding (in shares)	42,490,000	0

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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The per share liquidation preference (or restrictions) of stock classified as temporary equity that has a preference in involuntary liquidation considerably in excess of the par or stated value of the shares. The liquidation preference is the difference between the preference in liquidation and the par or stated values of the share. 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. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

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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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