Annual report pursuant to Section 13 and 15(d)

Federal Income Tax Provision Compared With Statutory Rates (Detail)

v3.21.1
Federal Income Tax Provision Compared With Statutory Rates (Detail)
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Income Tax Disclosure [Abstract]      
Statutory regular federal income tax rate (21.00%) (21.00%) (21.00%)
Change in valuation allowance 16.10% 35.00% 28.60%
State tax benefit (net of federal benefit) (4.80%) (7.00%) (3.10%)
Research credits 0.60% 2.10% (1.70%)
Foreign amounts with no tax benefit (0.10%)    
Non-deductible expenses (4.10%) 2.40% 0.30%
Effect of change in rate 9.70% (20.00%) 0.50%
Expired net operating loss carryforwards 3.70% 10.70%  
Other 0.60% (2.60%) (3.30%)
Total 0.70% (0.40%) 0.30%