Stock-Based Compensation - Compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Stock-based compensation expense
Stock-based compensation expense	$ 8,260	$ 8,642
Research and development expenses
Stock-based compensation expense
Stock-based compensation expense	3,477	2,531
General and administrative expenses
Stock-based compensation expense
Stock-based compensation expense	4,783	$ 6,111
Stock options.
Stock-based compensation expense
Unrecognized compensation cost	$ 61,000
Unrecognized compensation cost expected to be recognized over a weighted average period	2 years 7 months 6 days

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

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