Annual report pursuant to Section 13 and 15(d)

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

v3.8.0.1
Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Income Tax Disclosure [Abstract]      
Federal tax expense, at statutory rate 35.00% 35.00% 35.00%
State income tax expense, net of federal benefit 2.80% 2.80% 2.90%
Change in valuation allowance (0.10%) 0.00% 4.90%
Tax credit (1.70%) (6.10%) (0.00%)
Stock-based compensation (2.90%) (0.60%) (0.00%)
Federal tax reform - deferred rate change 14.60% 0.00% 0.00%
Other, net 1.00% 0.60% 0.10%
Effective tax rate 48.70% 31.70% 42.90%