Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Note 4 - Stock-based Compensation (Details Textual) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)	0	0		0	0
Immediately Vested Common Stock Issued in Lieu of Cash Bonuses [Member]
Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture, Total (in shares)	47,604			158,356
Immediately Vested Common Stock [Member]
Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture, Total (in shares)				166,648	27,341
Restricted Stock [Member]
Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture, Total (in shares)		32,500		309,700	688,167
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total	$ 6,800			$ 6,800
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)						1 year 8 months 12 days
Restricted Stock [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)			2 years
Restricted Stock [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)			3 years
Share-based Payment Arrangement, Option [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total	$ 0			$ 0