Leases - Leases Balance Sheet Information (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Balance sheet information related to leases
Lease assets	$ 18,780
Tenant receivable, assets	4,096
Total lease assets	22,876
Lease liabilities, current	3,145	$ 0
Lease liabilities, long term	27,256
Total lease liabilities	$ 30,401

Amount of operating lease assets, including right to use assets and receivable related to tenant improvement allowance.

No definition available.

Name:	supn_LesseeOperatingLeaseAssets
Namespace Prefix:	supn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of current and non-current operating lease liabilities.

+ References

No definition available.

+ Details

Name:	supn_LesseeOperatingLeaseLiabilities
Namespace Prefix:	supn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Receivable for amounts due related to tenant improvement allowance, representing the additional amount of payments that the lessee can elect to make in connection with tenant and capital improvement allowances under the terms of the lease.

+ References

No definition available.

+ Details

Name:	supn_TenantReceivableLeasesAdditionalAllowanceForTenantAndCapitalImprovement
Namespace Prefix:	supn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Present value of lessee's discounted obligation for lease payments from operating lease, classified as current.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

+ Details

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

- Definition

Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent.

+ References

+ Details

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

- Definition

Amount of lessee's right to use underlying asset under operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

+ Details

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