The number of share-based compensation plans.

No definition available.

Name:	srrk_NumberOfShareBasedCompensationPlans
Namespace Prefix:	srrk_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Increase in share reserved and available for issuance, as percentage of outstanding shares of common stock.

+ References

No definition available.

+ Details

Name:	srrk_ShareBasedCompensationArrangementByShareBasedPaymentAwardIncreaseInShareReservedAndAvailableForIssuanceAsPercentageOfOutstandingSharesOfCommonStock
Namespace Prefix:	srrk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
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

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

- Definition

Number of additional shares authorized for issuance under share-based payment arrangement.

+ References

No definition available.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of shares authorized for issuance under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_PlanNameAxis=srrk_StockOptionAndIncentivePlan2018Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=srrk_EquityIncentivePlan2017Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Equity-Based Compensation - 2018 Plan (Details)		12 Months Ended
Equity-Based Compensation - 2018 Plan (Details)	May 11, 2018 shares	Dec. 31, 2019 item	Dec. 31, 2017 shares
Share-based Compensation Arrangement by Share-based Payment Award
Number of share-based compensation plans \| item		3
2018 Plan
Share-based Compensation Arrangement by Share-based Payment Award
Additional shares authorized under stock-based plans (in shares)	352,204
Shares authorized for issuance	3,139,274
Increase as percentage of outstanding shares	4.00%
Vesting period	4 years
2017 Plan
Share-based Compensation Arrangement by Share-based Payment Award
Additional shares authorized under stock-based plans (in shares)	0
Shares authorized for issuance			3,455,330
Vesting period			4 years