Fair Value Measurements - Additional Information (Details)	Dec. 31, 2017 USD ($)
Fair Value Disclosures [Abstract]
Milestone payment, minimum (as a percent)	26.30%
Milestone payment, maximum (as a percent)	85.00%
Milestone payment, minimum	$ 0
Milestone payment, maximum	$ 69,000,000

For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid, expressed as a percentage.

No definition available.

+ Details

Name:	acor_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHighPercentage
Namespace Prefix:	acor_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

For contingent consideration arrangements and indemnification assets recognized in connection with a business combination, this element represents an estimate of the low-end of the potential range (undiscounted) of the consideration which may be paid, expressed as a percentage.

+ References

No definition available.

+ Details

Name:	acor_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueLowPercentage
Namespace Prefix:	acor_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

+ Details

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

- Definition

+ References

+ Details

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

- References

No definition available.

+ Details

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