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Balance Sheet Components (Narrative) (Details)
12 Months Ended
Dec. 31, 2019
USD ($)
segment
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Balance Sheet Related Disclosures [Abstract]      
Provisions for excess and obsolete inventory $ 3,878,000 $ 2,904,000 $ 2,866,000
Amortization expense 7,000,000.0 8,300,000 11,000,000.0
Intangible assets impairment charges $ 0 0 0
Number of reportable segments | segment 2    
Goodwill impairment charges $ 0 0 $ 0
Accumulated goodwill impairment charges 74,200,000 $ 74,200,000  
Equity securities without readily determinable fair value, cumulative downward adjustments for price change and impairment loss 1,600,000    
Cumulative upward adjustments for price changes $ 200,000