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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Long-lived assets other than financial instruments, long-term customer relationships of a financial institution, mortgage and other servicing rights, deferred policy acquisition costs, and deferred tax assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-SubTopic 10
-Section 50
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- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Business Segment and Geographic Region Information - Revenue and Long-Lived Assets (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue and long-lived assets by geographic region
Revenue	$ 105,683	$ 95,374	$ 119,333	$ 122,185	$ 116,396	$ 104,482	$ 102,790	$ 86,893	$ 442,575	$ 410,561	$ 266,980	$ 266,980
Long-Lived Assets	70,982				56,796				70,982	56,796		52,523
United States.
Revenue and long-lived assets by geographic region
Revenue									342,802	313,916		191,261
Long-Lived Assets	66,089				56,089				66,089	56,089		52,006
Europe
Revenue and long-lived assets by geographic region
Revenue									29,417	26,936		25,436
Asia Pacific
Revenue and long-lived assets by geographic region
Revenue									70,356	69,709		50,283
Long-Lived Assets	$ 4,893				$ 707				4,893	707		517
International \| Revenue \| Geographic concentration risk
Revenue and long-lived assets by geographic region
Revenue									$ 388,300	$ 348,500		$ 213,800
Percentage of revenue									87.70%	84.90%		80.00%