Note 10 - Stock-based Compensation - RSU Activity (Details) - Restricted Stock Units (RSUs) [Member]	9 Months Ended
Sep. 30, 2021 $ / shares shares
Balance (in shares) \| shares	845,106
Balance, weighted average issuance price (in dollars per share) \| $ / shares	$ 0.14
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares) \| shares	0
Granted, weighted average issuance price (in dollars per share) \| $ / shares	$ 0
Expired/Cancelled (in shares) \| shares	(540,576)
Expired/Cancelled, weighted average issuance price (in dollars per share) \| $ / shares	$ 0.13
Vested (in shares) \| shares	(220,728)
Vested, weighted average issuance price (in dollars per share) \| $ / shares	$ 0.09
Balance (in shares) \| shares	83,802
Balance, weighted average issuance price (in dollars per share) \| $ / shares	$ 0.13

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(3)
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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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Number of shares under non-option equity instrument agreements that were either cancelled or expired.

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