Income Taxes - Summary of Reconciliation of Unrecognized Tax Expense (Benefits) (Details) $ in Thousands	12 Months Ended
Dec. 31, 2017 USD ($)
Income Tax Disclosure [Abstract]
Unrecognized tax benefits balance at December 31, 2016	$ 2,389
Increase related to current year tax positions	1,436
Increase related to prior year tax positions	58
Settlements	0
Lapse in statute of limitations	0
Unrecognized tax benefits balance at December 31, 2017	$ 3,883

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- Definition

Amount of unrecognized tax benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=65882285&loc=SL6600010-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Unrecognized Tax Benefit
-URI http://asc.fasb.org/extlink&oid=6527854

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Amount of decrease in unrecognized tax benefits resulting from foreign currency translation.

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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