XML 15 R65.htm IDEA: XBRL DOCUMENT v3.19.3
Income Taxes - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Income Tax Disclosure [Abstract]    
U.S. federal statutory rate 21.00% 35.00%
Net operating loss carryforwards $ 51,800,000 $ 42,313,000.0