Selected Statements of Operations Data (Details Textual) - Segment	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Selected Statements of Operations Data (Textual)
Number of reportable segments	1
Percent of total revenues	96.00%	98.00%	90.00%

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
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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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-Name Accounting Standards Codification
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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