Annual report pursuant to Section 13 and 15(d)

Basis of Presentation and Summary of Significant Accounting Policies - Estimated Remaining Performance Obligations - Additional Information (Details)

v3.10.0.1
Basis of Presentation and Summary of Significant Accounting Policies - Estimated Remaining Performance Obligations - Additional Information (Details)
Dec. 31, 2018
USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-01-01  
Accounting Policies [Line Items]  
Estimated remaining performance obligations for contractually committed revenues $ 29,300,000
Estimated remaining performance obligations for contractually committed revenues recognition period 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01  
Accounting Policies [Line Items]  
Estimated remaining performance obligations for contractually committed revenues $ 20,900,000
Estimated remaining performance obligations for contractually committed revenues recognition period 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01  
Accounting Policies [Line Items]  
Estimated remaining performance obligations for contractually committed revenues $ 14,300,000
Estimated remaining performance obligations for contractually committed revenues recognition period 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-01-01  
Accounting Policies [Line Items]  
Estimated remaining performance obligations for contractually committed revenues $ 700,000
Estimated remaining performance obligations for contractually committed revenues recognition period 3 years