Stockholders' Equity (Stock Option and RSU Activity) (Details) shares in Thousands	9 Months Ended
Sep. 30, 2021 $ / shares shares
Number of options
Ending outstanding number (in shares)	9,727
Stock options
Number of options
Beginning outstanding number (in shares)	6,813
Granted (in shares)	3,143
Exercised (options) or Vested (RSUs) (in shares)	(28)
Canceled/forfeited/expired (in shares)	(201)
Ending outstanding number (in shares)	9,727
Weighted average exercise price
Beginning balance (in usd per share) \| $ / shares	$ 1.10
Granted (in usd per share) \| $ / shares	1.47
Exercised (options) or Vested (RSUs) (in usd per share) \| $ / shares	0.96
Canceled/forfeited/expired (in usd per share) \| $ / shares	1.22
Ending balance (in usd per share) \| $ / shares	$ 1.22
Restricted Stock Units (RSUs)
Number of RSUs
Beginning balance (in shares)	34
Shares granted (in shares)	446
Exercised (options) or Vested (RSUs) (in shares)	(34)
Canceled/forfeited/expired (in shares)	0
Ending balance (in shares)	446
Weighted average grant date fair value
Beginning balance (in usd per share) \| $ / shares	$ 1.50
Granted (in usd per share) \| $ / shares	0.95
Exercised (options) or Vested (RSUs)(in usd per share) \| $ / shares	1.50
Canceled/forfeited/expired (in usd per share) \| $ / shares	1.50
Ending balance (in usd per share) \| $ / shares	$ 0.95

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

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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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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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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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Weighted average price of options that were either forfeited or expired.

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

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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

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Number of share options (or share units) exercised during the current period.

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