Income Taxes - Significant Components of Deferred Income Taxes (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Net operating loss carryforwards	$ 74,876	$ 66,400
Deferred revenue	150	8
Lease liability	806	923
Stock-based compensation	6,847	5,805
Tax credits	4,503	3,687
Other	2,514	1,473
Total deferred tax assets	89,696	78,296
Deferred tax liabilities:
Intangible assets	6,087	7,559
Right-of-use assets	713	841
Total deferred tax liabilities	6,800	8,400
Deferred tax assets, net	82,896	69,896
Valuation allowance	82,896	69,896
Total deferred tax liability	$ 0	$ 0