Debt instrument covenants, cash and cash equivalents threshold limit.

No definition available.

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Period Type:	instant

- Definition

Debt instrument prepayment fee percentage.

+ References

No definition available.

+ Details

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- Definition

Debt instrument principal and interest payment period.

+ References

No definition available.

+ Details

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- Definition

Interest only extension, cash percentage of outstanding principal.

+ References

No definition available.

+ Details

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- Definition

Loan agreement amendment date.

+ References

No definition available.

+ Details

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Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Loan agreement amendment date one.

+ References

No definition available.

+ Details

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Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Loan agreement amendment date three.

+ References

No definition available.

+ Details

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Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Loan agreement amendment date two.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Percentage of obligation to pay closing fees and final payment.

+ References

No definition available.

+ Details

Name:	svra_PercentageOfObligationToPayClosingFeesAndFinalPayment
Namespace Prefix:	svra_
Data Type:	dtr-types:percentItemType
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

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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+ Details

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

- Definition

Amount of the fee that accompanies borrowing money under the debt instrument.

+ References

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

- Definition

Description of the frequency of periodic payments (monthly, quarterly, annual).

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Balance Type:	na
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- Definition

The average effective interest rate during the reporting period.

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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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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Latest date the outstanding debt instruments are required to be repaid, in YYYY-MM-DD format.

+ References

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Description of the payment terms of the debt instrument (for example, whether periodic payments include principal and frequency of payments) and discussion about any contingencies associated with the payment.

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Period Type:	duration

- Definition

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

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Balance Type:	credit
Period Type:	duration

- Definition

Amount of cash outflow for cost from early extinguishment and prepayment of debt. Includes, but is not limited to, third-party cost, premium paid, and other fee paid to lender directly for debt extinguishment or debt prepayment. Excludes accrued interest.

+ References

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- Definition

The cash outflow paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt.

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Balance Type:	credit
Period Type:	duration

- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

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Long-term Debt - Additional Information (Detail) - USD ($)			9 Months Ended
	Apr. 21, 2022	Apr. 28, 2017	Sep. 30, 2022
Debt Instrument [Line Items]
Repayment of outstanding amounts under Loan Agreement			$ 26,350,000
Loan and Security Agreement [Member] \| Silicon Valley Bank [Member]
Debt Instrument [Line Items]
Loan agreement amendment date		Oct. 31, 2017
Loan agreement amendment date one		Dec. 04, 2018
Loan agreement amendment date two		Jan. 31, 2020
Loan agreement amendment date three		Mar. 30, 2021
Loan and Security Agreement [Member] \| Silicon Valley Bank [Member] \| Term Loan [Member]
Debt Instrument [Line Items]
Loan agreement amendment date	Apr. 21, 2022
Principal amount	$ 26,500,000	$ 25,000,000.0
Repayment of outstanding amounts under Loan Agreement		25,000,000.0
Prepayment fee		100,000
Payment of debt issuance cost			$ 100,000
End of term charge		$ 1,400,000
Percentage of obligation to pay closing fees and final payment	2.75%
Debt instrument payment description			Pursuant to the Amended Loan Agreement, the loan has an interest-only monthly payment through April 21, 2026 (the “Interest-Only Period”) and thereafter equal monthly installments of principal plus interest over 12 months until April 21, 2027 (the “Maturity Date”). However, the Company may elect to extend the Interest-Only Period until the Maturity Date if it maintains cash and cash equivalents equal to at least 1.75 times the outstanding principal amount of the loan during the fifth year. If the Interest-Only Period is extended, all principal and unpaid interest is due and payable on the Maturity Date
Debt instrument principal and interest payment period	12 months
Debt instrument, maturity rate range, end	Apr. 21, 2027
Interest only extension cash percentage of outstanding principal	1.75%
Frequency of principal plus interest repayment period	equal monthly installments
Interest rate, basis spread	0.50%
Debt instrument, interest rate	3.00%
Extinguishment Of Debt			$ 0
Loan and Security Agreement [Member] \| Silicon Valley Bank [Member] \| Term Loan [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Debt instrument covenants cash and cash equivalents threshold limit	$ 40,000,000.0
Loan and Security Agreement [Member] \| Silicon Valley Bank [Member] \| Term Loan [Member] \| Before First Anniversary Closing Date [Member}
Debt Instrument [Line Items]
Prepayment fee percentage	4.25%
Loan and Security Agreement [Member] \| Silicon Valley Bank [Member] \| Term Loan [Member] \| After First And Before Second Anniversary Closing Date
Debt Instrument [Line Items]
Prepayment fee percentage	1.00%