XML 250 R55.htm IDEA: XBRL DOCUMENT v3.10.0.1

Summary of Significant Accounting Policies - Cash, Marketable Securities, and Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Unbilled Contracts Receivable	$ 7.4	$ 23.3
Cash and Cash Equivalents
Maximum time period for which an investment is considered a cash equivalent	3 months
Minimum
Marketable Securities
Maturity period of fixed income investments	3 months
Maturity period of marketable securities to be classified as long-term	12 months
Minimum | Property, Equipment, and Leasehold Improvements
Property and Equipment
Estimated useful life of property and equipment and leasehold improvements	3 years
Maximum | Property, Equipment, and Leasehold Improvements
Property and Equipment
Estimated useful life of property and equipment and leasehold improvements	5 years

X

- Definition

Represents the maximum original maturity period of investments classified as cash equivalents.

+ References

No definition available.

+ Details

Name:	sncr_CashEquivalentsOriginalMaturityPeriodMaximum
Namespace Prefix:	sncr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Represents the maturity period of fixed income investments under marketable securities.

+ References

No definition available.

+ Details

Name:	sncr_MarketableSecuritiesFixedIncomeInvestmentsMaturityPeriod
Namespace Prefix:	sncr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Represents the maturity period of marketable securities to be classified as long-term.

+ References

No definition available.

+ Details

Name:	sncr_MarketableSecuritiesMaturityPeriod
Namespace Prefix:	sncr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- References

No definition available.

+ Details

Name:	us-gaap_CashAndCashEquivalentsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- References

No definition available.

+ Details

Name:	us-gaap_MarketableSecuritiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- References

No definition available.

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

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.

+ References

No definition available.

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Unbilled amounts due for services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the entity and, at a minimum, one other party. An example would be amounts associated with contracts or programs where the recognized revenue for performance thereunder exceeds the amounts billed under the terms thereof as of the date of the balance sheet.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.3(c)(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 912
-SubTopic 310
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=68054760&loc=d3e55302-109406

+ Details

Name:	us-gaap_UnbilledContractsReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=sncr_PropertyEquipmentAndLeaseholdImprovementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: