Income Taxes - Components of Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Net operating loss carryforwards	$ 14,011	$ 2,649
Stock based compensation	6,459	4,663
59 (e) expenditures and amortization	6,222	5,902
Federal R&D and orphan drug credits	5,107	486
License fee	3,224	2,538
Other	1,024	967
Gross deferred tax assets	36,047	17,205
Valuation allowance	(35,513)	(16,441)
Total deferred tax assets	534	764
Deferred tax liabilities:
Lease Asset	114	244
Other	73	90
Total deferred tax liabilities	187	334
Total net deferred tax assets	$ 347	$ 430