Stock-Based Compensation - Assumptions Used in Determining Fair Value of Stock Options (Details) - $ / shares	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Stock-Based Compensation
Options to purchase common stock granted to employees and directors	198,200	643,629
Average risk free interest rate	1.30%	0.30%
Expected lives (years)	3 years 9 months 18 days	3 years 10 months 24 days
Expected volatility	105.00%	85.00%
Weighted average exercise price of options granted during the period (per share)	$ 0.60	$ 4.20

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

Net number of share options (or share units) granted during the period.

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- Definition

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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No definition available.

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- Definition

Expected term of 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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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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