XML 97 R75.htm IDEA: XBRL DOCUMENT v3.8.0.1
Income Taxes - Narrative (Details) - USD ($)
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Operating Loss Carryforwards [Line Items]      
U.S. federal income tax rate (percent) 34.00% 34.00% 34.00%
Undistributed earnings of foreign subsidiaries $ 0 $ 1,200,000 $ 800,000
Limitation on use of net operating loss, cumulative ownership change, more than 50.00%    
Limitation on use of net operating loss, cumulative ownership change, period of change 3 years    
Decrease in deferred tax assets due to tax reform of 2017 $ 26,000,000    
Federal      
Operating Loss Carryforwards [Line Items]      
Increase (decrease) in valuation allowance for deferred tax assets (1,300,000) $ 2,000,000  
Net operating loss carryforwards 188,800,000    
Federal | Research and Development Tax Credit Carryforward      
Operating Loss Carryforwards [Line Items]      
Research and development credit carryforwards 2,800,000    
State      
Operating Loss Carryforwards [Line Items]      
Net operating loss carryforwards 104,400,000    
State | Research and Development Tax Credit Carryforward      
Operating Loss Carryforwards [Line Items]      
Research and development credit carryforwards $ 2,400,000