Annual report pursuant to Section 13 and 15(d)

Income Taxes -Schedule of Effective Income Tax Rate Reconciliation (Detail)

v3.10.0.1
Income Taxes -Schedule of Effective Income Tax Rate Reconciliation (Detail)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Income Tax Contingency [Line Items]    
Tax benefit at federal statutory rate (21.00%) (34.00%)
State income taxes (7.70%) (10.20%)
Permanent differences:    
Stock-based compensation (2.20%) (2.50%)
Meals and entertainment 0.10% 0.10%
Executive compensation 0.20%  
Change in effective tax rate   39.00%
Effective income tax rate 0.00% 0.00%
Domestic Tax Authority [Member]    
Permanent differences:    
Effective income tax rate reconciliation, prior year income taxes, percent 0.10% (2.80%)
Effective income tax rate reconciliation, tax credit, research, percent (1.90%) (1.40%)
Effective income tax rate reconciliation, change in deferred tax assets valuation allowance, percent 24.70% 1.30%
State and Local Jurisdiction [Member]    
Permanent differences:    
Effective income tax rate reconciliation, tax credit, research, percent (1.40%) (1.60%)
Effective income tax rate reconciliation, change in deferred tax assets valuation allowance, percent 9.10% 11.70%