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MAJOR CUSTOMERS | 12 Months Ended
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Dec. 31, 2019
Risks and Uncertainties [Abstract] |
MAJOR CUSTOMERS | MAJOR CUSTOMERS The following customers contributed 10% or more of the Company's revenue in at least one of the years ended December 31, 2019, 2018 and 2017:
| Year ended December 31,
| 2019 |  | 2018 |  | 2017
Verizon Communications Inc. | 17% |  | 17% |  | 17%
AT&T Inc. | 12% |  | * |  | *
* Less than 10% of total revenue. At December 31, 2019, one customer accounted for 10% or more of the Company's accounts receivable balance, representing approximately 22% of total accounts receivable. At December 31, 2018, two customers accounted for 10% or more of the Company's accounts receivable balance, representing approximately 32% in the aggregate of total accounts receivable. The Company performs ongoing credit evaluations of its customers and generally does not require collateral on accounts receivable. The Company maintains an allowance for doubtful accounts and such losses have been within management's expectations.

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- Definition The entire disclosure for any concentrations existing at the date of the financial statements that make an entity vulnerable to a reasonably possible, near-term, severe impact. This disclosure informs financial statement users about the general nature of the risk associated with the concentration, and may indicate the percentage of concentration risk as of the balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -URI http://asc.fasb.org/topic&trid=2134479 + Details
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- References No definition available. + Details
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