Debt Instrument, Event Of Default, Minimum Amount In Excess Of Indebtedness Trigger

No definition available.

Name:	selb_DebtInstrumentEventOfDefaultMinimumAmountInExcessOfIndebtednessTrigger
Namespace Prefix:	selb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Debt Instrument, Event Of Default, Minimum Assets Trigger

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of fee payable on early extinguishment of debt.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of final fee payment payable on aggregate principal amounts borrowed.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of payment greater than the preceding installment payments to be paid at final maturity date of debt.

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount, after accumulated amortization, of debt issuance costs related to line of credit arrangements. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

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Balance Type:	credit
Period Type:	duration

- Definition

Amount of the cost of borrowed funds accounted for as interest expense.

+ References

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+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The effective interest rate during the reporting period.

+ References

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- 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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Balance Type:	na
Period Type:	duration

- Definition

Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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+ Details

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- Details

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- Details

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Debt - Term Loans (Narrative) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Sep. 12, 2017	Mar. 31, 2020	Mar. 31, 2019	Sep. 30, 2017	Dec. 31, 2019
Line of Credit Facility [Line Items]
Minimum assets trigger		$ 300
Minimum amount in excess of indebtedness trigger		300
Interest expense		273	$ 396
2017 Term Loans
Line of Credit Facility [Line Items]
Term loan facility	$ 21,000	$ 16,100			$ 18,200
Loss on extinguishment of debt				$ 700
Debt issuance costs, line of credit arrangements (less than)	$ 100
Interest rate per annum		4.00%
Final payment fee (as a percent)		5.00%
Final payment fee		$ 1,100
Debt instrument, basis spread on variable rate		100.00%
Interest expense		$ 300	$ 400
2017 Term Loans \| Base Rate
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate	0.05%
2017 Term Loans \| Outstanding Balances
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate		105.00%
2017 Term Loans \| Prepaid after second anniversary
Line of Credit Facility [Line Items]
Prepayment fee (as a percent)		1.00%
Term Loans
Line of Credit Facility [Line Items]
Repayments of debt	$ 10,000