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.

No definition available.

+ Details

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

- Definition

Amount of increase (decrease) in carrying value of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

No definition available.

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsPeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash outflow to acquire asset without physical form usually arising from contractual or other legal rights, excluding goodwill.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireIntangibleAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Net cumulative worldwide sales to achieve milestone and trigger payment of milestone obligation.

+ References

No definition available.

+ Details

Name:	vnda_CumulativeNetSalesToAchieveMilestone
Namespace Prefix:	vnda_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	srt_ProductOrServiceAxis=vnda_HetliozMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Intangible Assets - HETLIOZ - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended	12 Months Ended			203 Months Ended
	Apr. 30, 2018	Jan. 31, 2014	Mar. 31, 2015	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Acquisition of intangible assets				$ 0	$ 0	$ 25,000
HETLIOZ®
Finite-Lived Intangible Assets [Line Items]
Acquisition of intangible assets		$ 8,000				$ 25,000	$ 37,500
Cumulative worldwide sales milestone	$ 250,000
Intangible assets capitalized			$ 25,000				$ 33,000