Income Taxes - Deferred Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Income Taxes
Valuation allowance	$ 639,510	$ 526,235
Deferred tax assets
Net operating loss carryforwards	399,287	358,109
Research and development tax credit carryforwards	67,035	52,319
Capitalized research costs	95,923	59,128
Reserves and accruals	34,898	22,781
Lease Liabilities	19,339	21,000
Stock based compensation	29,005	23,814
Other	9,449	9,162
Total deferred tax assets before valuation allowance	654,936	546,313
Less: valuation allowance	(639,510)	(526,235)
Total deferred tax assets after valuation allowance	15,426	20,078
Deferred tax liabilities
Fixed Assets	(1,524)	(1,219)
Right-of-use lease assets	(13,902)	(18,859)
Total deferred tax liabilities	(15,426)	(20,078)
Net deferred tax assets