Income Taxes - Components of the Company's Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 142,512	$ 118,897
Research and investment credits	35,285	11,154
Accruals and reserves	9,239	7,734
Depreciation	1,756	1,119
Stock-based compensation	5,451	5,404
Interest expense	3,197	2,466
Total deferred tax assets	197,440	146,774
Deferred tax liabilities:
Intangible assets	(2,678)	(1,002)
Convertible debt	(3,550)	(4,675)
Capitalized costs	(11,351)	(8,002)
Depreciation	(138)
Total deferred tax liabilities	(17,717)	(13,679)
Valuation allowance	(180,092)	(132,759)
Net deferred tax liabilities	$ (369)
Net deferred tax assets		$ 336