Quarterly report pursuant to Section 13 or 15(d)

Income Taxes - Additional Information (Detail)

v3.10.0.1
Income Taxes - Additional Information (Detail) - USD ($)
3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Dec. 31, 2017
Income Tax Disclosure [Abstract]          
Liability for unrecognized tax benefit, including related estimates of penalties and interest $ 0 $ 0 $ 0 $ 0  
Income tax provision (benefit) $ 10,000 $ 36,000 $ 42,000 $ 76,000  
Projected annual effective tax rate (10.00%) 0.90% 0.80% 0.90%  
Statutory tax rate     21.00%   34.00%