XML 49 R38.htm IDEA: XBRL DOCUMENT v3.7.0.1
Income taxes - Additional Information (Detail) - USD ($)
3 Months Ended 12 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Dec. 31, 2015
Dec. 31, 2016
Income Taxes [Line Items]        
Statutory federal income tax rate 34.00% 34.00%    
Effective income tax rate, percentage 0.00% 34.20%    
Percentage of tax benefits likelihood of being realized upon settlement of tax authority greater than 50%      
Unrecognized tax benefits $ 1,668,000     $ 1,668,000
Discontinued Operations, Disposed of [Member] | Advertising Business [Member]        
Income Taxes [Line Items]        
Tax loss resulting from the the disposal of discontinued operation     $ 4,375,000  
Uncertain tax position, reduction in deferred tax assets     1,668,000  
Benefit for income taxes recognized for the loss     $ 0  
Accrued interest and penalties to uncertain tax positions $ 0