Acquisitions (Details) - USD ($)
2 Months Ended 3 Months Ended 12 Months Ended 33 Months Ended
Jan. 19, 2018
Jan. 11, 2017
Mar. 31, 2018
Mar. 31, 2018
Mar. 31, 2017
Dec. 31, 2017
Dec. 31, 2019
Business Acquisition              
Goodwill     $ 887,800,000 $ 887,800,000   $ 884,900,000  
Revenue, Net       178,500,000 $ 168,300,000    
Loss from continuing operations       $ (400,000) $ (5,000,000)    
Loss from continuing operations, per basic share       $ 0.00 $ (0.06)    
Loss from continuing operations, per diluted share       $ 0.00 $ (0.06)    
Compex Corporation              
Business Acquisition              
Payments to Acquire Businesses, Gross $ 16,000,000            
Business Combination, Consideration Transferred 18,700,000            
Business Combination, Consideration Transferred, Other 600,000            
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual     2,600,000        
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual     $ 200,000        
Cash 200,000            
Receivables 1,700,000            
Inventories 2,100,000            
Property, plant, and equipment 2,100,000            
Business Combination, Contingent Consideration, Asset, Noncurrent 200,000            
Goodwill 2,900,000            
Assumed current liabilities (200,000)            
Total purchase price 18,700,000            
Business Acquisition, Goodwill, Expected Tax Deductible Amount 0            
Business Acquisition, Pro Forma Revenue       $ 179,100,000 $ 171,200,000    
Business Acquisition, Pro Forma Net Income (Loss)       $ 0 $ (4,400,000)    
Business Acquisition, Pro Forma Earnings Per Share, Basic       $ 0.00 $ (0.05)    
Business Acquisition, Pro Forma Earnings Per Share, Diluted       $ 0.00 $ (0.05)    
17Q1 Capacitor Acquisition              
Business Acquisition              
Payments to Acquire Businesses, Gross   $ 3,700,000       $ 2,500,000  
Scenario, Forecast | 17Q1 Capacitor Acquisition              
Business Acquisition              
Payments to Acquire Businesses, Gross             $ 1,200,000
Customer relationships | Compex Corporation              
Business Acquisition              
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill $ 7,300,000            
Finite-Lived Intangible Asset, Useful Life 10 years            
Unpatented technologies | Compex Corporation              
Business Acquisition              
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill $ 2,000,000            
Finite-Lived Intangible Asset, Useful Life 8 years            
Trademarks | Compex Corporation              
Business Acquisition              
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill $ 400,000            
Finite-Lived Intangible Asset, Useful Life 5 years            
Other liabilities | Compex Corporation              
Business Acquisition              
Payments to Acquire Businesses, Gross $ 1,000,000