Annual report pursuant to Section 13 and 15(d)

Income Taxes - Reconciliation of Statutory Tax Rates and Effective Tax Rates (Detail)

v3.8.0.1
Income Taxes - Reconciliation of Statutory Tax Rates and Effective Tax Rates (Detail)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Percentage of pre-tax income:      
U.S. federal statutory income tax rate 35.00% 35.00% 35.00%
State taxes, net of federal benefit 8.00% 3.00% 5.00%
Credits 1.00% 2.00% 1.00%
Non-deductible items (2.00%) (4.00%) 0.00%
Provision to return 1.00% 2.00% 0.00%
Stock based compensation shortfall (1.00%) (2.00%) (1.00%)
Change in federal rate (43.00%) 0.00% 0.00%
Change in state rate 2.00% 0.00% 0.00%
Intercomapny elimination adjustments (3.00%) 0.00% 0.00%
Change in fair value of warrants 3.00% 0.00% 0.00%
Change in valuation allowance (7.00%) (33.00%) (44.00%)
Change in subsidiary basis 4.00% (3.00%) 3.00%
Other 0.00% 0.00% 1.00%
Effective income tax rate (2.00%) 0.00% 0.00%