Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Accumulated depreciation	$ 5,021	$ 6,252
Accumulated amortization	$ 73	$ 73
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, par value	$ 0.0005	$ 0.0005
Preferred stock, shares issued
Common stock, shares authorized	50,000,000	50,000,000
Common stock, par value	$ 0.0005	$ 0.0005
Common stock, shares issued	28,256,275	28,225,615
Treasury stock, shares	16,652,022	16,652,022

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Face amount or stated value per share of common stock.

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Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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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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