Stock-Based Compensation - Service Based Stock Options - Others (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expenses	$ 475	$ 4,952
Stock option awards - Service based awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	2,288,386	1,103,938
Vested options, exercisable (in shares)	2,898,104
Vested options exercisable at an average price (in dollars per share)	$ 6.85
Stock based compensation expenses	$ 1,491	$ 2,300
Unvested options (in shares)	2,819,582
Unrecognized stock-based compensation expenses	$ 2,200
Period of recognition for unrecognized stock-based compensation expenses	2 years 2 months 12 days

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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