Discontinued Operations - Cash Flow (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018
Net Cash Provided by (Used in) Discontinued Operations [Abstract]
Depreciation and amortization	$ 302	$ 160
Stock-based compensation expense	102	2,687
Intangible asset impairment charge	27,638
Loss on disposal of property and equipment	391
Cash flows from operating activities	$ 28,433	$ 2,847

The amount of gains (losses) on disposal of property, plant and equipment pertaining to discontinued operations.

No definition available.

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- Definition

The amount of impairment charge of intangible assets of discontinued operations.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of stock based compensation expense relating to discontinued operations.

+ References

No definition available.

+ Details

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

- Definition

Amount of cash inflow (outflow) of operating activities of discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3521-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=109222650&loc=SL51721673-107760

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

Amount of deprecation and amortization expense attributable to property, plant and equipment and intangible assets of discontinued operations.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=109222650&loc=SL51721673-107760

+ Details

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Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

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