Income Taxes - Summary of Company's Net Deferred Tax Assets (Liabilities) (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Intangibles, including acquired in-process research and development	$ 1,091	$ 1,201
Capitalized start-up costs	421	463
Net operating loss carryforwards	63,245	34,234
Research and development credit carryforwards	19,417	11,766
Operating lease liability	5,008
Deferred revenue	7,843	12,199
Equity-based compensation	7,092	4,064
Accruals and allowances	1,245	1,359
Gross deferred tax assets	105,362	65,286
Deferred tax asset valuation allowance	(98,513)	(64,046)
Total deferred tax assets	6,849	1,240
Deferred tax liabilities:
Fixed assets	(1,633)	(1,240)
Operating lease right-of-use assets	(5,216)
Total deferred tax liabilities	$ (6,849)	$ (1,240)