Income Tax - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Depreciation of property and equipment, net	$ 131	$ 98
Research and experimental capitalization	30,429	22,476
Share-based compensation	3,422	1,787
Accrued expenses	707	1,800
Government grants	467	189
Deferred revenue	4,354	3,378
Qualified donation	22,992	12,947
Lease liability	2,967	3,738
Net operating loss carry forwards	295,313	241,397
Less: valuation allowance	(357,956)	(284,072)	$ (189,684)
Total Deferred tax assets	2,826	3,738
Deferred tax liabilities:
Right-of-use assets	(2,826)	(3,738)
Deferred tax assets, net	$ 0	$ 0