Quarterly report pursuant to Section 13 or 15(d)

Income Taxes - Additional Information (Detail)

v3.8.0.1
Income Taxes - Additional Information (Detail) - USD ($)
 3 Months Ended 12 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Dec. 31, 2017
Income Taxes [Line Items]      
U.S. federal statutory tax rate 21.00%    
Percentage of TCJA limitations on net operating loss carryforwards to taxable income 80.00%    
Maximum      
Income Taxes [Line Items]      
U.S. federal statutory tax rate     35.00%
Federal      
Income Taxes [Line Items]      
Net operating loss carryforwards $ 60,600,000    
Net operating loss carryforwards expiration period carried forward for 20 years and are expected to be available to fully offset taxable income earned in future tax years.    
Current income tax expense benefit $ 0 $ 0  
Deferred income tax expense benefit 0 $ 0  
Federal and State      
Income Taxes [Line Items]      
Net operating loss carryforwards $ 60,600,000