Annual report pursuant to Section 13 and 15(d)

Intangible Assets, Net and Goodwill (Schedule of Identifiable Intangible Assets) (Details)

v3.10.0.1
Intangible Assets, Net and Goodwill (Schedule of Identifiable Intangible Assets) (Details) - USD ($)
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Summary of Identifiable Intangible Assets [Line Items]      
Amortization expense $ 2,980,000 $ 3,883,000 $ 5,146,000
Gross carrying amount 37,198,000 37,198,000  
Accumulated amortization (26,044,000) (23,064,000)  
Net carrying amount 11,154,000 14,134,000  
Intangible assets not subject to amortization 115,421,000 115,421,000  
Intangible assets, net 126,575,000 129,555,000  
Patents And Purchased Technology [Member]      
Summary of Identifiable Intangible Assets [Line Items]      
Gross carrying amount 14,198,000 14,198,000  
Accumulated amortization (11,981,000) (10,651,000)  
Customer Relationships [Member]      
Summary of Identifiable Intangible Assets [Line Items]      
Gross carrying amount 23,000,000 23,000,000  
Accumulated amortization $ (14,063,000) $ (12,413,000)