Stock-Based Compensation - Service Based Stock Options - Others (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expenses	$ 361	$ 250	$ 558	$ (276)
Stock option awards - service based awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)			1,872,162	2,252,344
Forfeited (in shares)			385,278	440,026
Expirations (in shares)			1,333,220	4,090,150
Stock based compensation expenses	315	$ 243	$ 1,050	$ 1,019
Unrecognized stock-based compensation expenses	$ 1,700		$ 1,700
Unrecognized stock-based compensation expense, weighted average remaining term (in years)			3 years

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of cost to be recognized for option under share-based payment arrangement.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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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.

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

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