Income Taxes - Components of the Net Deferred Tax Assets/Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Federal and state net operating loss carryforwards	$ 74,278	$ 45,228
Research and development tax credits	9,247	6,205
Lease liabilities	7,327	5,920
Accruals and other	3,354	2,172
Amortization	11,155	2,700
Deferred revenue	3,414	3,659
Deferred tax liabilities:
Other depreciation	(763)	(638)
Operating lease right-of-use assets	(6,231)	(5,904)
Total net deferred tax assets	101,781	59,342
Less valuation allowance	(101,781)	(59,342)
Deferred tax assets, net of allowance	$ 0	$ 0