Income Taxes - Effect Income Tax Rate Reconciliation (Detail)
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Income Tax Disclosure [Abstract]    
Federal statutory rate 34.00% 34.00%
State income taxes, net of federal benefit 4.80% 4.20%
Non-deductible expenses (1.90%) (2.10%)
Income tax credits 1.90% 1.60%
Valuation allowance (38.80%) (37.70%)
Effective tax rate 0.00% 0.00%