Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Deferred Tax Liabilities
Unrealized gains on investments	$ 117	$ 0	$ 0
Total Deferred Tax Liabilities	117	0	0
Deferred Tax Assets
Charitable contributions	37	45	53
Accrued expenses	3,857	2,398	1,857
Intangibles	503	589	783
Stock compensation	33,976	27,226	24,335
Property, plant & equipment	95	106	80
Unrealized loss on investment	0	8	23
Net operating losses	121,552	68,305	47,864
Capitalized R&D	175,145	137,328	112,848
R&D credit	48,074	35,103	23,799
Total deferred tax assets before valuation allowance	383,239	271,108	211,642
Valuation allowance	(383,122)	(271,108)	(211,642)
Total deferred tax assets	117	0	0
Net deferred tax assets	$ 0	$ 0	$ 0