Annual report pursuant to Section 13 and 15(d)

Revenue Contract Balances (Details)

v3.19.3.a.u2
Revenue Contract Balances (Details) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]    
Contract with Customer, Performance Obligation Satisfied in Previous Period $ 0  
Contract assets 1,089,000 $ 485,000
Contract with Customer, Liability 11,600,000 $ 11,300,000
Contract with Customer, Liability, Revenue Recognized $ 9,700,000  
Revenue, Performance Obligation, Description of Timing 30 to 60 days  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01    
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]    
Revenue, Remaining Performance Obligation, Amount $ 11,300,000  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)    
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]    
Revenue, Remaining Performance Obligation, Amount $ 19,300,000