Commitments and Contingencies - Concentrations of Credit Risk (Details) - customer	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Accounts receivable \| Credit risk \| Customers
Customer Concentration
Concentration Risk Number of Customers	2	2
Concentration risk (as a percent)	63.40%	52.30%
Revenues \| Customer concentration
Customer Concentration
Concentration Risk Number of Customers		2
Concentration risk (as a percent)	49.60%	66.70%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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