Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Net operating loss carryforwards	$ 138,685	$ 168,606
Accrued expenditures	17,842	9,169
Research and development credit, net	31,109	9,321
Research and development expenditures	62,432	13,525
Share-based compensation	19,753	17,085
Other	0	1,466
Capital lease	4,198	4,980
Deferred tax liabilities:
Right of use asset—capital lease	(3,204)	(3,684)
Depreciation	(140)	(154)
Other	(86)	0
Net deferred tax asset before valuation allowance	270,589	220,314
Valuation allowance	(270,589)	(220,314)
Net deferred tax asset	$ 0	$ 0