No definition available.

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Namespace Prefix:	us-gaap_
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- Definition

Amount of transaction price allocated to performance obligation that has not been recognized as revenue.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130556-203045

+ Details

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- 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

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- Definition

Period in which remaining performance obligation is expected to be recognized as revenue, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130556-203045

+ Details

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Period Type:	instant

- Details

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- Details

Name:	us-gaap_TypeOfArrangementAxis=selb_LicenseAndSupplyObligationMember
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- Details

Name:	us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis=2016-12-03
Namespace Prefix:
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Period Type:

Revenue Arrangements - Transaction Price Allocated to Future Performance Obligation (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 02, 2016
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 16.3
Spark License Agreement
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 2.3	$ 12.3
Spark License Agreement \| License and Supply Obligation
Revenue from Contract with Customer [Abstract]
Remaining performance obligation		$ 7.1
Spark License Agreement \| License and Supply Obligation \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2016-12-03
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, period		4 years