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v3.19.3.a.u2

Summary of Significant Accounting Policies - Concentration of Risk (Details) - customer | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Revenue | Customer concentration risk |  |  |
Concentration of Risk |  |  |
Number of customers | 3 | 2 | 2
Revenue | Customer concentration risk | Ten largest customers |  |  |
Concentration of Risk |  |  |
Number of customers | 10 | 10 | 10
Percentage of concentration risk | 74.10% | 76.90% | 73.30%
Revenue | Customer concentration risk | First customer |  |  |
Concentration of Risk |  |  |
Percentage of concentration risk | 18.20% | 20.10% | 24.90%
Revenue | Customer concentration risk | Second customer |  |  |
Concentration of Risk |  |  |
Percentage of concentration risk | 14.20% | 12.10% | 13.10%
Revenue | Customer concentration risk | Third customer |  |  |
Concentration of Risk |  |  |
Percentage of concentration risk | 12.00% |  |
Consolidated accounts receivable | Credit concentration risk |  |  |
Concentration of Risk |  |  |
Number of customers | 3 | 2 |
Consolidated accounts receivable | Credit concentration risk | First customer |  |  |
Concentration of Risk |  |  |
Percentage of concentration risk | 24.90% | 21.90% |
Consolidated accounts receivable | Credit concentration risk | Second customer |  |  |
Concentration of Risk |  |  |
Percentage of concentration risk | 15.30% | 11.50% |
Consolidated accounts receivable | Credit concentration risk | Third customer |  |  |
Concentration of Risk |  |  |
Percentage of concentration risk | 11.10% |  |

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- Definition 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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13531-108611 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13537-108611 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592 + Details
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