The fixed portion of the amount to be paid each year by the entity under the agreement.

No definition available.

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- Definition

Period from the first commercial product sale that royalties are owed, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

Future payments that could be paid upon achievement of certain milestones per agreement.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

The number of payments to be made or received under the agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	acrs_
Data Type:	xbrli:integerItemType
Balance Type:	na
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- Definition

The number of products related to the disclosure.

+ References

No definition available.

+ Details

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Namespace Prefix:	acrs_
Data Type:	xbrli:integerItemType
Balance Type:	na
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- Definition

Cash outflow for milestone achieved per agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	acrs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The minimum period before expiration of the agreement, starting from agreement effective date.

+ References

No definition available.

+ Details

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

- Definition

Cash outflow for consideration paid upfront per agreement.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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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- Definition

Number of shares of stock issued during the period as part of a transaction to acquire assets that do not qualify as a business combination.

+ References

No definition available.

+ Details

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

- Definition

Value of shares of stock issued during the period as part of a transaction to acquire assets that do not qualify as a business combination.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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Agreements Related to Intellectual Property (Details) $ in Thousands			1 Months Ended
	Mar. 24, 2016 USD ($) installment item shares	Dec. 31, 2015 USD ($)	Apr. 30, 2017 USD ($)	Feb. 29, 2016 USD ($)	Aug. 31, 2012 USD ($)
Assignment Agreement and Finder's Services Agreement [Member]
Agreements Related to Intellectual Property
Term of agreement, minimum					15 years
Assignment Agreement and Finder's Services Agreement [Member] \| Achievement Of Dosing Of First Subject With A101 \| General and administrative expense.
Agreements Related to Intellectual Property
Milestone payment				$ 300
Assignment Agreement and Finder's Services Agreement [Member] \| Achievement Of Specified Regulatory Milestones [Member] \| General and administrative expense.
Agreements Related to Intellectual Property
Milestone payment			$ 1,000
Finders Services Agreement \| Achievement Of Specified Commercial Milestones \| Maximum
Agreements Related to Intellectual Property
Potential future milestone payments					$ 4,500
Stock Purchase Agreement [Member] \| Achievement Of Specified Commercial Milestones
Agreements Related to Intellectual Property
Period from first commercial product sale that royalties are owed (in years)	10 years
Stock Purchase Agreement [Member] \| Achievement Of Pre Commercialization Milestones
Agreements Related to Intellectual Property
Number of products \| item	3
Stock Purchase Agreement [Member] \| Selling Stockholders
Agreements Related to Intellectual Property
Entity stock issued in stock purchase \| shares	159,420
Stock Purchase Agreement [Member] \| Selling Stockholders \| Research and development expense.
Agreements Related to Intellectual Property
Upfront payment made	$ 600
Amount of required annual payment under the contract	100
Fair value of common stock issued	$ 2,355
Number of annual payments \| installment	6
Stock Purchase Agreement [Member] \| Selling Stockholders \| Achievement Of Specified Commercial Milestones \| Maximum
Agreements Related to Intellectual Property
Potential future milestone payments	$ 22,500
Stock Purchase Agreement [Member] \| Selling Stockholders \| Achievement Of Pre Commercialization Milestones \| Maximum
Agreements Related to Intellectual Property
Potential future milestone payments	$ 18,000
License Agreement \| Columbia
Agreements Related to Intellectual Property
Amount of required annual payment under the contract		$ 10
License Agreement \| Columbia \| Achievement Of Specified Commercial Milestones
Agreements Related to Intellectual Property
Period from first commercial product sale that royalties are owed (in years)		10 years
License Agreement \| Columbia \| Achievement Of Specified Commercial Milestones \| Maximum
Agreements Related to Intellectual Property
Potential future milestone payments		$ 11,600